essay on conservation of energy

Energy Conservation Essay for Students and Children

500 words energy conservation essay.

Energy conservation refers to the efforts made to reduce the consumption of energy. The energy on Earth is not in unlimited supply. Furthermore, energy can take plenty of time to regenerate. This certainly makes it essential to conserve energy. Most noteworthy, energy conservation is achievable either by using energy more efficiently or by reducing the amount of service usage.

Importance of Energy Conservation

First of all, energy conservation plays an important role in saving non-renewable energy resources. Furthermore, non-renewable energy sources take many centuries to regenerate. Moreover, humans consume energy at a faster rate than it can be produced. Therefore, energy conservation would lead to the preservation of these precious non-renewable sources of energy.

Energy conservation will reduce the expenses related to fossil fuels. Fossil fuels are very expensive to mine. Therefore, consumers are required to pay higher prices for goods and services. Energy conservation would certainly reduce the amount of fossil fuel being mined. This, in turn, would reduce the costs of consumers.

Consequently, energy conservation would strengthen the economy as consumers will have more disposable income to spend on goods and services.

Energy conservation is good for scientific research. This is because; energy conservation gives researchers plenty of time to conduct researches.

Therefore, these researchers will have more time to come up with various energy solutions and alternatives. Humans must ensure to have fossil fuels as long as possible. This would give me enough time to finding practical solutions.

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Another important reason for energy conservation is environmental protection. This is because various energy sources are significantly harmful to the environment. Furthermore, the burning of fossil fuels considerably pollutes the atmosphere. Moreover, nuclear energy creates dangerous nuclear waste. Hence, energy conservation will lead to environmental protection.

Energy conservation would also result in the good health of humans. Furthermore, the pollution released due to energy sources is harmful to the human body. The air pollution due to fossil fuels can cause various respiratory problems. Energy sources can pollute water which could cause several harmful diseases in humans. Nuclear waste can cause cancer and other deadly problems in the human body.

Measures to Conserve Energy

Energy taxation is a good measure from the government to conserve energy. Furthermore, several countries apply energy or a carbon tax on energy users. This tax would certainly put pressure on energy users to reduce their energy consumption. Moreover, carbon tax forces energy users to shift to other energy sources that are less harmful.

Building design plays a big role in energy conservation. An excellent way to conserve energy is by performing an energy audit in buildings. Energy audit refers to inspection and analysis of energy use in a building. Most noteworthy, the aim of the energy audit is to appropriately reduce energy input.

Another important way of energy conservation is by using energy-efficient products. Energy-efficient products are those that use lesser energy than their normal counterparts. One prominent example can be using an energy-efficient bulb rather than an incandescent light bulb.

In conclusion, energy conservation must be among the utmost priorities of humanity. Mahatma Gandhi was absolutely right when he said, “the earth provides enough to satisfy every man’s needs but not every man’s greed”. This statement pretty much sums up the importance of energy conservation. Immediate implementation of energy conservation measures is certainly of paramount importance.

FAQs on Energy Conservation

Q1 state one way in which energy conservation is important.

A1 One way in which energy conservation is important is that it leads to the preservation of fossil fuels.

Q2 Why energy taxation is a good measure to conserve energy?

A2 Energy taxation is certainly a good measure to conserve energy. This is because energy taxation puts financial pressure on energy users to reduce their energy consumption.

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Energy Conservation Essay

When people think about conservation, they often think about protecting the environment from human exploitation. However, conservation is a concept that encompasses many facets, including health and beauty, animal welfare and natural resources. Here are some sample essays on energy conservation.

100 Words Essay On Energy Conservation

Conservation is an important factor in maintaining the balance of life on earth. Human lives and industries depend on energy, so conservation is necessary for the continued existence of mankind. Furthermore, energy conservation promotes sustainable development. This means development that respects the environment and promotes healthy ecosystems instead of harmful ones.

Energy conservation helps protect the environment from harmful industrial processes like carbon dioxide emissions. Energy conservation has become an increasingly important issue as the world population continues to grow and our energy resources dwindle. We must use energy more efficiently if we are to preserve our planet and ensure that future generations have access to the resources they will need.

200 Words Essay On Energy Conservation

Energy is essential to our daily lives. Energy conservation is one of the most important topics when discussing environmentalism and sustainable living. It encourages sustainable development while protecting the natural environment. After all, without energy we couldn’t power our homes, run our businesses or get from A to B.

How To Save Energy

As our world becomes increasingly more digitalised, it’s important that we start to think about how we can conserve energy in our everyday lives. Here are a few tips on how you can start saving energy today:

Turn off electronics and appliances when you’re not using them. This includes your TV, computer, game consoles, lights, etc.

Unplug chargers for devices that aren’t in use. Even if they’re not turned on, they’re still using up energy.

Invest in energy-efficient appliances. Look for the Energy Star label when you next need to buy a new fridge, washing machine, etc.

Use natural light as much as possible during the daytime. Open up your curtains and blinds to let in some sunshine!

Dress appropriately for the weather. In winter, wear layers of clothing instead of cranking up the heating. In summer, wear loose fitting clothes and turn on a fan rather than using air conditioning.

500 Words Essay On Energy And Conservation

Energy is used to power transportation, communication and heating homes. Because of this, we should conserve energy whenever possible. Doing so helps the environment and our economy. Energy saving refers to efforts to reduce energy consumption. The energy on earth is not infinite. Also, energy can take a long time to recover. This undoubtedly makes saving energy imperative. Most notably, energy savings can be achieved by using energy more efficiently or reducing service usage.

What Is Energy And Conservation?

Energy is the ability to do work with any form of fuel. It is essential for living creatures and the environment. Conservation is the conscious management of energy. There are various sources of energy such as solar, wind, water, geothermal and biomass. Conservation is crucial in determining the state of our world.

What Is Physical Energy?

Physical energy is the power generated by bombardment, combustion or movement. All electric and mechanical engines consume energy, and it is converted into motion. The human body needs physical energy to survive and carry out daily tasks. Energy also powers weapons and tools used in warfare, agriculture and industry. Energy is also used to power your car or bike while you drive or ride.

Why Energy Conservation Is Essential?

First of all, energy saving plays an important role in saving non-renewable energy. Furthermore, non-renewable energy sources take many centuries to regenerate. Since humans consume energy faster than they can produce it, therefore, saving energy will lead to the conservation of these valuable non-renewable energy sources.

Energy conservation is essential in a growing economy. People use a lot of energy every day. This includes household and business energy usage. Everyone needs to make careful decisions about which energy sources to use and how to use them. This helps the economy grow without destroying or depleting the natural environment.

How Can We Conserve Energy?

Consumers can also help conserve energy by making smart choices. Replacing old appliances with more efficient models helps lower consumption as well as emissions. Many people don't realise that they're wasting power when they leave their lights on or their car running outside. In general, making simple choices saves a lot of energy.

Governments play an important role in promoting energy conservation. They issue laws regarding what resources can be used in vehicles and factories. They also regulate production and consumption of various energy sources such as coal, oil, natural gas and electricity. This ensures that all nations use the same standards for resource conservation and consumption alike. It ensures that everyone uses resources effectively and conserves energy at the same rate.

Energy conservation will lower the costs associated with fossil fuels. The extraction of fossil fuels is prohibitively expensive. As a result, consumers must pay higher prices for goods and services. Energy conservation would almost certainly decrease the amount of fossil fuel mined. This, in turn, would lower consumer costs.

Energy conservation is an essential way to run a sustainable economy. Consumers can save money by making smarter choices when using energy resources. Governments promote conservation in many ways to ensure everyone uses resources effectively and conserves energy wisely. Energy conservation is a vital part of modern life!

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4 Conservation of Energy

4–1 What is energy?

In this chapter, we begin our more detailed study of the different aspects of physics, having finished our description of things in general. To illustrate the ideas and the kind of reasoning that might be used in theoretical physics, we shall now examine one of the most basic laws of physics, the conservation of energy.

There is a fact, or if you wish, a law , governing all natural phenomena that are known to date. There is no known exception to this law—it is exact so far as we know. The law is called the conservation of energy . It states that there is a certain quantity, which we call energy, that does not change in the manifold changes which nature undergoes. That is a most abstract idea, because it is a mathematical principle; it says that there is a numerical quantity which does not change when something happens. It is not a description of a mechanism, or anything concrete; it is just a strange fact that we can calculate some number and when we finish watching nature go through her tricks and calculate the number again, it is the same. (Something like the bishop on a red square, and after a number of moves—details unknown—it is still on some red square. It is a law of this nature.) Since it is an abstract idea, we shall illustrate the meaning of it by an analogy.

Imagine a child, perhaps “Dennis the Menace,” who has blocks which are absolutely indestructible, and cannot be divided into pieces. Each is the same as the other. Let us suppose that he has $28$ blocks. His mother puts him with his $28$ blocks into a room at the beginning of the day. At the end of the day, being curious, she counts the blocks very carefully, and discovers a phenomenal law—no matter what he does with the blocks, there are always $28$ remaining! This continues for a number of days, until one day there are only $27$ blocks, but a little investigating shows that there is one under the rug—she must look everywhere to be sure that the number of blocks has not changed. One day, however, the number appears to change—there are only $26$ blocks. Careful investigation indicates that the window was open, and upon looking outside, the other two blocks are found. Another day, careful count indicates that there are $30$ blocks! This causes considerable consternation, until it is realized that Bruce came to visit, bringing his blocks with him, and he left a few at Dennis’ house. After she has disposed of the extra blocks, she closes the window, does not let Bruce in, and then everything is going along all right, until one time she counts and finds only $25$ blocks. However, there is a box in the room, a toy box, and the mother goes to open the toy box, but the boy says “No, do not open my toy box,” and screams. Mother is not allowed to open the toy box. Being extremely curious, and somewhat ingenious, she invents a scheme! She knows that a block weighs three ounces, so she weighs the box at a time when she sees $28$ blocks, and it weighs $16$ ounces. The next time she wishes to check, she weighs the box again, subtracts sixteen ounces and divides by three. She discovers the following: \begin{equation} \label{Eq:I:4:1} \begin{pmatrix} \text{number of}\\ \text{blocks seen} \end{pmatrix}+ \frac{(\text{weight of box})-\text{$16$ ounces}}{\text{$3$ ounces}}= \text{constant}. \end{equation} \begin{align} \begin{pmatrix} \text{number of}\\ \text{blocks seen} \end{pmatrix}&+ \frac{(\text{weight of box})-\text{$16$ ounces}}{\text{$3$ ounces}}\notag\\[1ex] \label{Eq:I:4:1} &=\text{constant}. \end{align} There then appear to be some new deviations, but careful study indicates that the dirty water in the bathtub is changing its level. The child is throwing blocks into the water, and she cannot see them because it is so dirty, but she can find out how many blocks are in the water by adding another term to her formula. Since the original height of the water was $6$ inches and each block raises the water a quarter of an inch, this new formula would be: \begin{align} \begin{pmatrix} \text{number of}\\ \text{blocks seen} \end{pmatrix}&+ \frac{(\text{weight of box})-\text{$16$ ounces}} {\text{$3$ ounces}}\notag\\[1ex] \label{Eq:I:4:2} &+\frac{(\text{height of water})-\text{$6$ inches}} {\text{$1/4$ inch}}= \text{constant}. \end{align} \begin{align} \begin{pmatrix} \text{number of}\\ \text{blocks seen} \end{pmatrix}&+ \frac{(\text{weight of box})-\text{$16$ ounces}} {\text{$3$ ounces}}\notag\\[1ex] &+\frac{(\text{height of water})-\text{$6$ inches}} {\text{$1/4$ inch}}\notag\\[2ex] \label{Eq:I:4:2} &=\text{constant}. \end{align} In the gradual increase in the complexity of her world, she finds a whole series of terms representing ways of calculating how many blocks are in places where she is not allowed to look. As a result, she finds a complex formula, a quantity which has to be computed , which always stays the same in her situation.

What is the analogy of this to the conservation of energy? The most remarkable aspect that must be abstracted from this picture is that there are no blocks . Take away the first terms in ( 4.1 ) and ( 4.2 ) and we find ourselves calculating more or less abstract things. The analogy has the following points. First, when we are calculating the energy, sometimes some of it leaves the system and goes away, or sometimes some comes in. In order to verify the conservation of energy, we must be careful that we have not put any in or taken any out. Second, the energy has a large number of different forms , and there is a formula for each one. These are: gravitational energy, kinetic energy, heat energy, elastic energy, electrical energy, chemical energy, radiant energy, nuclear energy, mass energy. If we total up the formulas for each of these contributions, it will not change except for energy going in and out.

It is important to realize that in physics today, we have no knowledge of what energy is . We do not have a picture that energy comes in little blobs of a definite amount. It is not that way. However, there are formulas for calculating some numerical quantity, and when we add it all together it gives “$28$”—always the same number. It is an abstract thing in that it does not tell us the mechanism or the reasons for the various formulas.

4–2 Gravitational potential energy

Conservation of energy can be understood only if we have the formula for all of its forms. I wish to discuss the formula for gravitational energy near the surface of the Earth, and I wish to derive this formula in a way which has nothing to do with history but is simply a line of reasoning invented for this particular lecture to give you an illustration of the remarkable fact that a great deal about nature can be extracted from a few facts and close reasoning. It is an illustration of the kind of work theoretical physicists become involved in. It is patterned after a most excellent argument by Mr. Carnot on the efficiency of steam engines. 1

Consider weight-lifting machines—machines which have the property that they lift one weight by lowering another. Let us also make a hypothesis: that there is no such thing as perpetual motion with these weight-lifting machines. (In fact, that there is no perpetual motion at all is a general statement of the law of conservation of energy.) We must be careful to define perpetual motion. First, let us do it for weight-lifting machines. If, when we have lifted and lowered a lot of weights and restored the machine to the original condition, we find that the net result is to have lifted a weight , then we have a perpetual motion machine because we can use that lifted weight to run something else. That is, provided the machine which lifted the weight is brought back to its exact original condition , and furthermore that it is completely self-contained —that it has not received the energy to lift that weight from some external source—like Bruce’s blocks.

A very simple weight-lifting machine is shown in Fig. 4–1 . This machine lifts weights three units “strong.” We place three units on one balance pan, and one unit on the other. However, in order to get it actually to work, we must lift a little weight off the left pan. On the other hand, we could lift a one-unit weight by lowering the three-unit weight, if we cheat a little by lifting a little weight off the other pan. Of course, we realize that with any actual lifting machine, we must add a little extra to get it to run. This we disregard, temporarily . Ideal machines, although they do not exist, do not require anything extra. A machine that we actually use can be, in a sense, almost reversible: that is, if it will lift the weight of three by lowering a weight of one, then it will also lift nearly the weight of one the same amount by lowering the weight of three.

We imagine that there are two classes of machines, those that are not reversible, which includes all real machines, and those that are reversible, which of course are actually not attainable no matter how careful we may be in our design of bearings, levers, etc. We suppose, however, that there is such a thing—a reversible machine—which lowers one unit of weight (a pound or any other unit) by one unit of distance, and at the same time lifts a three-unit weight. Call this reversible machine, Machine $A$. Suppose this particular reversible machine lifts the three-unit weight a distance $X$. Then suppose we have another machine, Machine $B$, which is not necessarily reversible, which also lowers a unit weight a unit distance, but which lifts three units a distance $Y$. We can now prove that $Y$ is not higher than $X$; that is, it is impossible to build a machine that will lift a weight any higher than it will be lifted by a reversible machine. Let us see why. Let us suppose that $Y$ were higher than $X$. We take a one-unit weight and lower it one unit height with Machine $B$, and that lifts the three-unit weight up a distance $Y$. Then we could lower the weight from $Y$ to $X$, obtaining free power , and use the reversible Machine $A$, running backwards, to lower the three-unit weight a distance $X$ and lift the one-unit weight by one unit height. This will put the one-unit weight back where it was before, and leave both machines ready to be used again! We would therefore have perpetual motion if $Y$ were higher than $X$, which we assumed was impossible. With those assumptions, we thus deduce that $Y$ is not higher than $X$, so that of all machines that can be designed, the reversible machine is the best.

We can also see that all reversible machines must lift to exactly the same height . Suppose that $B$ were really reversible also. The argument that $Y$ is not higher than $X$ is, of course, just as good as it was before, but we can also make our argument the other way around, using the machines in the opposite order, and prove that $X$ is not higher than $Y$. This, then, is a very remarkable observation because it permits us to analyze the height to which different machines are going to lift something without looking at the interior mechanism . We know at once that if somebody makes an enormously elaborate series of levers that lift three units a certain distance by lowering one unit by one unit distance, and we compare it with a simple lever which does the same thing and is fundamentally reversible, his machine will lift it no higher, but perhaps less high. If his machine is reversible, we also know exactly how high it will lift. To summarize: every reversible machine, no matter how it operates, which drops one pound one foot and lifts a three-pound weight always lifts it the same distance, $X$. This is clearly a universal law of great utility. The next question is, of course, what is $X$?

Suppose we have a reversible machine which is going to lift this distance $X$, three for one. We set up three balls in a rack which does not move, as shown in Fig. 4–2 . One ball is held on a stage at a distance one foot above the ground. The machine can lift three balls, lowering one by a distance $1$. Now, we have arranged that the platform which holds three balls has a floor and two shelves, exactly spaced at distance $X$, and further, that the rack which holds the balls is spaced at distance $X$, (a). First we roll the balls horizontally from the rack to the shelves, (b), and we suppose that this takes no energy because we do not change the height. The reversible machine then operates: it lowers the single ball to the floor, and it lifts the rack a distance $X$, (c). Now we have ingeniously arranged the rack so that these balls are again even with the platforms. Thus we unload the balls onto the rack, (d); having unloaded the balls, we can restore the machine to its original condition. Now we have three balls on the upper three shelves and one at the bottom. But the strange thing is that, in a certain way of speaking, we have not lifted two of them at all because, after all, there were balls on shelves $2$ and $3$ before. The resulting effect has been to lift one ball a distance $3X$. Now, if $3X$ exceeds one foot, then we can lower the ball to return the machine to the initial condition, (f), and we can run the apparatus again. Therefore $3X$ cannot exceed one foot, for if $3X$ exceeds one foot we can make perpetual motion. Likewise, we can prove that one foot cannot exceed $3X$ , by making the whole machine run the opposite way, since it is a reversible machine. Therefore $3X$ is neither greater nor less than a foot , and we discover then, by argument alone, the law that $X=\tfrac{1}{3}$ foot. The generalization is clear: one pound falls a certain distance in operating a reversible machine; then the machine can lift $p$ pounds this distance divided by $p$. Another way of putting the result is that three pounds times the height lifted, which in our problem was $X$, is equal to one pound times the distance lowered, which is one foot in this case. If we take all the weights and multiply them by the heights at which they are now, above the floor, let the machine operate, and then multiply all the weights by all the heights again, there will be no change . (We have to generalize the example where we moved only one weight to the case where when we lower one we lift several different ones—but that is easy.)

We call the sum of the weights times the heights gravitational potential energy —the energy which an object has because of its relationship in space, relative to the earth. The formula for gravitational energy, then, so long as we are not too far from the earth (the force weakens as we go higher) is \begin{equation} \label{Eq:I:4:3} \begin{pmatrix} \text{gravitational}\\ \text{potential energy}\\ \text{for one object} \end{pmatrix}= (\text{weight})\times(\text{height}). \end{equation} It is a very beautiful line of reasoning. The only problem is that perhaps it is not true. (After all, nature does not have to go along with our reasoning.) For example, perhaps perpetual motion is, in fact, possible. Some of the assumptions may be wrong, or we may have made a mistake in reasoning, so it is always necessary to check. It turns out experimentally , in fact, to be true.

The general name of energy which has to do with location relative to something else is called potential energy. In this particular case, of course, we call it gravitational potential energy . If it is a question of electrical forces against which we are working, instead of gravitational forces, if we are “lifting” charges away from other charges with a lot of levers, then the energy content is called electrical potential energy . The general principle is that the change in the energy is the force times the distance that the force is pushed, and that this is a change in energy in general: \begin{equation} \label{Eq:I:4:4} \begin{pmatrix} \text{change in}\\ \text{energy} \end{pmatrix}= (\text{force})\times \begin{pmatrix} \text{distance force}\\ \text{acts through} \end{pmatrix}. \end{equation} We will return to many of these other kinds of energy as we continue the course.

The principle of the conservation of energy is very useful for deducing what will happen in a number of circumstances. In high school we learned a lot of laws about pulleys and levers used in different ways. We can now see that these “laws” are all the same thing , and that we did not have to memorize $75$ rules to figure it out. A simple example is a smooth inclined plane which is, happily, a three-four-five triangle (Fig. 4–3 ). We hang a one-pound weight on the inclined plane with a pulley, and on the other side of the pulley, a weight $W$. We want to know how heavy $W$ must be to balance the one pound on the plane. How can we figure that out? If we say it is just balanced, it is reversible and so can move up and down, and we can consider the following situation. In the initial circumstance, (a), the one pound weight is at the bottom and weight $W$ is at the top. When $W$ has slipped down in a reversible way, (b), we have a one-pound weight at the top and the weight $W$ the slant distance, or five feet, from the plane in which it was before. We lifted the one-pound weight only three feet and we lowered $W$ pounds by five feet. Therefore $W=\tfrac{3}{5}$ of a pound. Note that we deduced this from the conservation of energy , and not from force components. Cleverness, however, is relative. It can be deduced in a way which is even more brilliant, discovered by Stevinus and inscribed on his tombstone. 2 Figure 4–4 explains that it has to be $\tfrac{3}{5}$ of a pound, because the chain does not go around. It is evident that the lower part of the chain is balanced by itself, so that the pull of the five weights on one side must balance the pull of three weights on the other, or whatever the ratio of the legs. You see, by looking at this diagram, that $W$ must be $\tfrac{3}{5}$ of a pound. (If you get an epitaph like that on your gravestone, you are doing fine.)

Let us now illustrate the energy principle with a more complicated problem, the screw jack shown in Fig. 4–5 . A handle $20$ inches long is used to turn the screw, which has $10$ threads to the inch. We would like to know how much force would be needed at the handle to lift one ton ($2000$ pounds). If we want to lift the ton one inch, say, then we must turn the handle around ten times. When it goes around once it goes approximately $126$ inches. The handle must thus travel $1260$ inches, and if we used various pulleys, etc., we would be lifting our one ton with an unknown smaller weight $W$ applied to the end of the handle. So we find out that $W$ is about $1.6$ pounds. This is a result of the conservation of energy.

Take now the somewhat more complicated example shown in Fig. 4–6 . A rod or bar, $8$ feet long, is supported at one end. In the middle of the bar is a weight of $60$ pounds, and at a distance of two feet from the support there is a weight of $100$ pounds. How hard do we have to lift the end of the bar in order to keep it balanced, disregarding the weight of the bar? Suppose we put a pulley at one end and hang a weight on the pulley. How big would the weight $W$ have to be in order for it to balance? We imagine that the weight falls any arbitrary distance—to make it easy for ourselves suppose it goes down $4$ inches—how high would the two load weights rise? The center rises $2$ inches, and the point a quarter of the way from the fixed end lifts $1$ inch. Therefore, the principle that the sum of the heights times the weights does not change tells us that the weight $W$ times $4$ inches down, plus $60$ pounds times $2$ inches up, plus $100$ pounds times $1$ inch has to add up to nothing: \begin{equation} \label{Eq:I:4:5} -4W+(2)(60)+(1)(100)=0,\quad W=\text{$55$ lb}. \end{equation} \begin{equation} \begin{gathered} -4W+(2)(60)+(1)(100)=0,\\[.5ex] W=\text{$55$ lb}. \end{gathered} \label{Eq:I:4:5} \end{equation} Thus we must have a $55$-pound weight to balance the bar. In this way we can work out the laws of “balance”—the statics of complicated bridge arrangements, and so on. This approach is called the principle of virtual work , because in order to apply this argument we had to imagine that the structure moves a little—even though it is not really moving or even movable . We use the very small imagined motion to apply the principle of conservation of energy.

4–3 Kinetic energy

To illustrate another type of energy we consider a pendulum (Fig. 4–7 ). If we pull the mass aside and release it, it swings back and forth. In its motion, it loses height in going from either end to the center. Where does the potential energy go? Gravitational energy disappears when it is down at the bottom; nevertheless, it will climb up again. The gravitational energy must have gone into another form. Evidently it is by virtue of its motion that it is able to climb up again, so we have the conversion of gravitational energy into some other form when it reaches the bottom.

We must get a formula for the energy of motion. Now, recalling our arguments about reversible machines, we can easily see that in the motion at the bottom must be a quantity of energy which permits it to rise a certain height, and which has nothing to do with the machinery by which it comes up or the path by which it comes up. So we have an equivalence formula something like the one we wrote for the child’s blocks. We have another form to represent the energy. It is easy to say what it is. The kinetic energy at the bottom equals the weight times the height that it could go, corresponding to its velocity: $\text{K.E.}= WH$. What we need is the formula which tells us the height by some rule that has to do with the motion of objects. If we start something out with a certain velocity, say straight up, it will reach a certain height; we do not know what it is yet, but it depends on the velocity—there is a formula for that. Then to find the formula for kinetic energy for an object moving with velocity $V$, we must calculate the height that it could reach, and multiply by the weight. We shall soon find that we can write it this way: \begin{equation} \label{Eq:I:4:6} \text{K.E.}=WV^2/2g. \end{equation} Of course, the fact that motion has energy has nothing to do with the fact that we are in a gravitational field. It makes no difference where the motion came from. This is a general formula for various velocities. Both ( 4.3 ) and ( 4.6 ) are approximate formulas, the first because it is incorrect when the heights are great, i.e., when the heights are so high that gravity is weakening; the second, because of the relativistic correction at high speeds. However, when we do finally get the exact formula for the energy, then the law of conservation of energy is correct.

4–4 Other forms of energy

We can continue in this way to illustrate the existence of energy in other forms. First, consider elastic energy. If we pull down on a spring, we must do some work, for when we have it down, we can lift weights with it. Therefore in its stretched condition it has a possibility of doing some work. If we were to evaluate the sums of weights times heights, it would not check out—we must add something else to account for the fact that the spring is under tension. Elastic energy is the formula for a spring when it is stretched. How much energy is it? If we let go, the elastic energy, as the spring passes through the equilibrium point, is converted to kinetic energy and it goes back and forth between compressing or stretching the spring and kinetic energy of motion. (There is also some gravitational energy going in and out, but we can do this experiment “sideways” if we like.) It keeps going until the losses—Aha! We have cheated all the way through by putting on little weights to move things or saying that the machines are reversible, or that they go on forever, but we can see that things do stop, eventually. Where is the energy when the spring has finished moving up and down? This brings in another form of energy: heat energy .

Inside a spring or a lever there are crystals which are made up of lots of atoms, and with great care and delicacy in the arrangement of the parts one can try to adjust things so that as something rolls on something else, none of the atoms do any jiggling at all. But one must be very careful. Ordinarily when things roll, there is bumping and jiggling because of the irregularities of the material, and the atoms start to wiggle inside. So we lose track of that energy; we find the atoms are wiggling inside in a random and confused manner after the motion slows down. There is still kinetic energy, all right, but it is not associated with visible motion. What a dream! How do we know there is still kinetic energy? It turns out that with thermometers you can find out that, in fact, the spring or the lever is warmer , and that there is really an increase of kinetic energy by a definite amount. We call this form of energy heat energy , but we know that it is not really a new form, it is just kinetic energy—internal motion. (One of the difficulties with all these experiments with matter that we do on a large scale is that we cannot really demonstrate the conservation of energy and we cannot really make our reversible machines, because every time we move a large clump of stuff, the atoms do not remain absolutely undisturbed, and so a certain amount of random motion goes into the atomic system. We cannot see it, but we can measure it with thermometers, etc.)

There are many other forms of energy, and of course we cannot describe them in any more detail just now. There is electrical energy, which has to do with pushing and pulling by electric charges. There is radiant energy, the energy of light, which we know is a form of electrical energy because light can be represented as wigglings in the electromagnetic field. There is chemical energy, the energy which is released in chemical reactions. Actually, elastic energy is, to a certain extent, like chemical energy, because chemical energy is the energy of the attraction of the atoms, one for the other, and so is elastic energy. Our modern understanding is the following: chemical energy has two parts, kinetic energy of the electrons inside the atoms, so part of it is kinetic, and electrical energy of interaction of the electrons and the protons—the rest of it, therefore, is electrical. Next we come to nuclear energy, the energy which is involved with the arrangement of particles inside the nucleus, and we have formulas for that, but we do not have the fundamental laws. We know that it is not electrical, not gravitational, and not purely kinetic, but we do not know what it is. It seems to be an additional form of energy. Finally, associated with the relativity theory, there is a modification of the laws of kinetic energy, or whatever you wish to call it, so that kinetic energy is combined with another thing called mass energy . An object has energy from its sheer existence . If I have a positron and an electron, standing still doing nothing—never mind gravity, never mind anything—and they come together and disappear, radiant energy will be liberated, in a definite amount, and the amount can be calculated. All we need know is the mass of the object. It does not depend on what it is—we make two things disappear, and we get a certain amount of energy. The formula was first found by Einstein; it is $E=mc^2$.

It is obvious from our discussion that the law of conservation of energy is enormously useful in making analyses, as we have illustrated in a few examples without knowing all the formulas. If we had all the formulas for all kinds of energy, we could analyze how many processes should work without having to go into the details. Therefore conservation laws are very interesting. The question naturally arises as to what other conservation laws there are in physics. There are two other conservation laws which are analogous to the conservation of energy. One is called the conservation of linear momentum. The other is called the conservation of angular momentum. We will find out more about these later. In the last analysis, we do not understand the conservation laws deeply. We do not understand the conservation of energy. We do not understand energy as a certain number of little blobs. You may have heard that photons come out in blobs and that the energy of a photon is Planck’s constant times the frequency. That is true, but since the frequency of light can be anything, there is no law that says that energy has to be a certain definite amount. Unlike Dennis’ blocks, there can be any amount of energy, at least as presently understood. So we do not understand this energy as counting something at the moment, but just as a mathematical quantity, which is an abstract and rather peculiar circumstance. In quantum mechanics it turns out that the conservation of energy is very closely related to another important property of the world, things do not depend on the absolute time . We can set up an experiment at a given moment and try it out, and then do the same experiment at a later moment, and it will behave in exactly the same way. Whether this is strictly true or not, we do not know. If we assume that it is true, and add the principles of quantum mechanics, then we can deduce the principle of the conservation of energy. It is a rather subtle and interesting thing, and it is not easy to explain. The other conservation laws are also linked together. The conservation of momentum is associated in quantum mechanics with the proposition that it makes no difference where you do the experiment, the results will always be the same. As independence in space has to do with the conservation of momentum, independence of time has to do with the conservation of energy, and finally, if we turn our apparatus, this too makes no difference, and so the invariance of the world to angular orientation is related to the conservation of angular momentum . Besides these, there are three other conservation laws, that are exact so far as we can tell today, which are much simpler to understand because they are in the nature of counting blocks.

The first of the three is the conservation of charge , and that merely means that you count how many positive, minus how many negative electrical charges you have, and the number is never changed. You may get rid of a positive with a negative, but you do not create any net excess of positives over negatives. Two other laws are analogous to this one—one is called the conservation of baryons . There are a number of strange particles, a neutron and a proton are examples, which are called baryons. In any reaction whatever in nature, if we count how many baryons are coming into a process, the number of baryons 3 which come out will be exactly the same. There is another law, the conservation of leptons . We can say that the group of particles called leptons are: electron, muon, and neutrino. There is an antielectron which is a positron, that is, a $-1$ lepton. Counting the total number of leptons in a reaction reveals that the number in and out never changes, at least so far as we know at present.

These are the six conservation laws, three of them subtle, involving space and time, and three of them simple, in the sense of counting something.

With regard to the conservation of energy, we should note that available energy is another matter—there is a lot of jiggling around in the atoms of the water of the sea, because the sea has a certain temperature, but it is impossible to get them herded into a definite motion without taking energy from somewhere else. That is, although we know for a fact that energy is conserved, the energy available for human utility is not conserved so easily. The laws which govern how much energy is available are called the laws of thermodynamics and involve a concept called entropy for irreversible thermodynamic processes.

Finally, we remark on the question of where we can get our supplies of energy today. Our supplies of energy are from the sun, rain, coal, uranium, and hydrogen. The sun makes the rain, and the coal also, so that all these are from the sun. Although energy is conserved, nature does not seem to be interested in it; she liberates a lot of energy from the sun, but only one part in two billion falls on the earth. Nature has conservation of energy, but does not really care; she spends a lot of it in all directions. We have already obtained energy from uranium; we can also get energy from hydrogen, but at present only in an explosive and dangerous condition. If it can be controlled in thermonuclear reactions, it turns out that the energy that can be obtained from $10$ quarts of water per second is equal to all of the electrical power generated in the United States. With $150$ gallons of running water a minute, you have enough fuel to supply all the energy which is used in the United States today! Therefore it is up to the physicist to figure out how to liberate us from the need for having energy. It can be done.

Our point here is not so much the result, ( 4.3 ), which in fact you may already know, as the possibility of arriving at it by theoretical reasoning. ↩
Stevinus' tombstone has never been found. He used a similar diagram as his trademark. ↩
Counting antibaryons as $-1$ baryon. ↩

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7.6: Conservation of Energy

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Learning Objectives

By the end of this section, you will be able to:

Explain the law of the conservation of energy.
Describe some of the many forms of energy.
Define efficiency of an energy conversion process as the fraction left as useful energy or work, rather than being transformed, for example, into thermal energy.

Energy, as we have noted, is conserved, making it one of the most important physical quantities in nature. The law of conservation of energy can be stated as follows:

We have explored some forms of energy and some ways it can be transferred from one system to another. This exploration led to the definition of two major types of energy—mechanical energy $(KE + PE)$ and energy transferred via work done by nonconservative forces $(W_{nc})$ But energy takes many other forms, manifesting itself in many different ways, and we need to be able to deal with all of these before we can write an equation for the above general statement of the conservation of energy.

Other Forms of Energy than Mechanical Energy

At this point, we deal with all other forms of energy by lumping them into a single group called other energy $(OE)$. Then we can state the conservation of energy in equation form as

\[KE_i + PE_i + W_{nc} + OE_i = KE_f + PE_f + OE_f .\]

All types of energy and work can be included in this very general statement of conservation of energy. Kinetic energy is $KE$, work done by a conservative force is represented by $PE$, work done by nonconservative forces is $W_{nc}$ and all other energies are included as $OE$. This equation applies to all previous examples; in those situations $OE$ was constant, and so it subtracted out and was not directly considered.

Usefulness of the Energy Conservation Principle

The fact that energy is conserved and has many forms makes it very important. You will find that energy is discussed in many contexts, because it is involved in all processes. It will also become apparent that many situations are best understood in terms of energy and that problems are often most easily conceptualized and solved by considering energy.

When does $OE$ play a role? One example occurs when a person eats. Food is oxidized with the release of carbon dioxide, water, and energy. Some of this chemical energy is converted to kinetic energy when the person moves, to potential energy when the person changes altitude, and to thermal energy (another form of $OE$).

Some of the Many Forms of Energy

What are some other forms of energy? You can probably name a number of forms of energy not yet discussed. Many of these will be covered in later chapters, but let us detail a few here. Electrical energy is a common form that is converted to many other forms and does work in a wide range of practical situations. Fuels, such as gasoline and food, carry chemical energy that can be transferred to a system through oxidation. Chemical fuel can also produce electrical energy, such as in batteries. Batteries can in turn produce light, which is a very pure form of energy. Most energy sources on Earth are in fact stored energy from the energy we receive from the Sun. We sometimes refer to this as radiant energy , or electromagnetic radiation, which includes visible light, infrared, and ultraviolet radiation. Nuclear energy comes from processes that convert measurable amounts of mass into energy. Nuclear energy is transformed into the energy of sunlight, into electrical energy in power plants, and into the energy of the heat transfer and blast in weapons. Atoms and molecules inside all objects are in random motion. This internal mechanical energy from the random motions is called thermal energy , because it is related to the temperature of the object. These and all other forms of energy can be converted into one another and can do work.

Table gives the amount of energy stored, used, or released from various objects and in various phenomena. The range of energies and the variety of types and situations is impressive.

Problem-Solving Strategies for Energy

You will find the following problem-solving strategies useful whenever you deal with energy. The strategies help in organizing and reinforcing energy concepts. In fact, they are used in the examples presented in this chapter. The familiar general problem-solving strategies presented earlier—involving identifying physical principles, knowns, and unknowns, checking units, and so on —continue to be relevant here.

Step 1. Determine the system of interest and identify what information is given and what quantity is to be calculated. A sketch will help.

Step 2. Examine all the forces involved and determine whether you know or are given the potential energy from the work done by the forces. Then use step 3 or step 4.

Step 3. If you know the potential energies for the forces that enter into the problem, then forces are all conservative, and you can apply conservation of mechanical energy simply in terms of potential and kinetic energy. The equation expressing conservation of energy is

\[KE_i + PE_i = KE_f + PE_f.\]

Step 4. If you know the potential energy for only some of the forces, possibly because some of them are nonconservative and do not have a potential energy, or if there are other energies that are not easily treated in terms of force and work, then the conservation of energy law in its most general form must be used.

\[KE_i + PE_i + W_{nc} + OE_i = KE_f + PE_f + OE_f.\]

In most problems, one or more of the terms is zero, simplifying its solution. Do not calculate $W_c$, the work done by conservative forces; it is already incorporated in the $PE$ terms.

Step 5. You have already identified the types of work and energy involved (in step 2). Before solving for the unknown, eliminate terms wherever possible to simplify the algebra. For example, choose $h = 0$ at either the initial or final point, so that $PE_g$ is zero there. Then solve for the unknown in the customary manner.

Step 6. Check the answer to see if it is reasonable . Once you have solved a problem, reexamine the forms of work and energy to see if you have set up the conservation of energy equation correctly. For example, work done against friction should be negative, potential energy at the bottom of a hill should be less than that at the top, and so on. Also check to see that the numerical value obtained is reasonable. For example, the final speed of a skateboarder who coasts down a 3-m-high ramp could reasonably be 20 km/h, but not 80 km/h.

Transformation of Energy

The transformation of energy from one form into others is happening all the time. The chemical energy in food is converted into thermal energy through metabolism; light energy is converted into chemical energy through photosynthesis. In a larger example, the chemical energy contained in coal is converted into thermal energy as it burns to turn water into steam in a boiler. This thermal energy in the steam in turn is converted to mechanical energy as it spins a turbine, which is connected to a generator to produce electrical energy. (In all of these examples, not all of the initial energy is converted into the forms mentioned. This important point is discussed later in this section.)

Another example of energy conversion occurs in a solar cell. Sunlight impinging on a solar cell (Figure 7.7.1) produces electricity, which in turn can be used to run an electric motor. Energy is converted from the primary source of solar energy into electrical energy and then into mechanical energy.

A solar-powered aircraft flying over the sea. Solar cells are on the upper surface of the wings, where they are exposed to sunlight.

Even though energy is conserved in an energy conversion process, the output of useful energy or work will be less than the energy input. The efficiency $E_{ff}$ of an energy conversion process is defined as

\[Efficiency \, (E_{ff}) = \dfrac{useful \, energy \, or \, work \, output}{total \, energy \, input} = \dfrac{W_{out}}{E_{in}}.\]

Table lists some efficiencies of mechanical devices and human activities. In a coal-fired power plant, for example, about 40% of the chemical energy in the coal becomes useful electrical energy. The other 60% transforms into other (perhaps less useful) energy forms, such as thermal energy, which is then released to the environment through combustion gases and cooling towers.

Efficiency of the Human Body and Mechanical Devices

PhET Explorations: Masses and Springs

A realistic mass and spring laboratory. Hang masses from springs and adjust the spring stiffness and damping. You can even slow time. Transport the lab to different planets. A chart shows the kinetic, potential, and thermal energies for each spring.

The law of conservation of energy states that the total energy is constant in any process. Energy may change in form or be transferred from one system to another, but the total remains the same.
When all forms of energy are considered, conservation of energy is written in equation form as \[KE_i + PE_i + W_{nc} + OE_i = KE_f + PE_f + OE_f ,\] where $OE$ is all other forms of energy besides mechanical energy.
Commonly encountered forms of energy include electric energy, chemical energy, radiant energy, nuclear energy, and thermal energy.
Energy is often utilized to do work, but it is not possible to convert all the energy of a system to work.

The efficiency $E_{ff}$ of a machine or human is defined to be $E_{ff} = \frac{W_{out}}{E_{in}},$ where $W_{out}$ is useful work output and $E_{in}$ s the energy consumed.

7.6 Conservation of Energy

Learning objectives.

By the end of this section, you will be able to:

Explain the law of the conservation of energy.
Describe some of the many forms of energy.
Define efficiency of an energy conversion process as the fraction left as useful energy or work, rather than being transformed, for example, into thermal energy.

Law of Conservation of Energy

Energy, as we have noted, is conserved, making it one of the most important physical quantities in nature. The law of conservation of energy can be stated as follows:

Total energy is constant in any process. It may change in form or be transferred from one system to another, but the total remains the same.

We have explored some forms of energy and some ways it can be transferred from one system to another. This exploration led to the definition of two major types of energy—mechanical energy KE + PE KE + PE and energy transferred via work done by nonconservative forces ( W nc ) ( W nc ) . But energy takes many other forms, manifesting itself in many different ways, and we need to be able to deal with all of these before we can write an equation for the above general statement of the conservation of energy.

Other Forms of Energy than Mechanical Energy

At this point, we deal with all other forms of energy by lumping them into a single group called other energy ( OE OE ). Then we can state the conservation of energy in equation form as

All types of energy and work can be included in this very general statement of conservation of energy. Kinetic energy is KE KE , work done by a conservative force is represented by PE PE , work done by nonconservative forces is W nc W nc , and all other energies are included as OE OE . This equation applies to all previous examples; in those situations OE OE was constant, and so it subtracted out and was not directly considered.

Making Connections: Usefulness of the Energy Conservation Principle

When does OE OE play a role? One example occurs when a person eats. Food is oxidized with the release of carbon dioxide, water, and energy. Some of this chemical energy is converted to kinetic energy when the person moves, to potential energy when the person changes altitude, and to thermal energy (another form of OE OE ).

Some of the Many Forms of Energy

Table 7.1 gives the amount of energy stored, used, or released from various objects and in various phenomena. The range of energies and the variety of types and situations is impressive.

Problem-Solving Strategies for Energy

Step 1. Determine the system of interest and identify what information is given and what quantity is to be calculated. A sketch will help.

Step 2. Examine all the forces involved and determine whether you know or are given the potential energy from the work done by the forces. Then use step 3 or step 4.

In most problems, one or more of the terms is zero, simplifying its solution. Do not calculate W c W c , the work done by conservative forces; it is already incorporated in the PE PE terms.

Step 5. You have already identified the types of work and energy involved (in step 2). Before solving for the unknown, eliminate terms wherever possible to simplify the algebra. For example, choose h = 0 h = 0 at either the initial or final point, so that PE g PE g is zero there. Then solve for the unknown in the customary manner.

Transformation of Energy

Another example of energy conversion occurs in a solar cell. Sunlight impinging on a solar cell (see Figure 7.19 ) produces electricity, which in turn can be used to run an electric motor. Energy is converted from the primary source of solar energy into electrical energy and then into mechanical energy.

Even though energy is conserved in an energy conversion process, the output of useful energy or work will be less than the energy input. The efficiency Eff Eff of an energy conversion process is defined as

Table 7.2 lists some efficiencies of mechanical devices and human activities. In a coal-fired power plant, for example, about 40% of the chemical energy in the coal becomes useful electrical energy. The other 60% transforms into other (perhaps less useful) energy forms, such as thermal energy, which is then released to the environment through combustion gases and cooling towers.

PhET Explorations

Masses and springs.

1 Representative values

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by Chris Woodford . Last updated: November 28, 2022.

Photo: The conservation of energy: James Prescott Joule calculated that the water at the bottom of Niagara falls would be about a fifth of a degree warmer than the water at the top. Why? The water loses potential energy as it falls, which is converted into heat. [2] Photo courtesy of the Carol M. Highsmith Archive, Library of Congress, Prints and Photographs Division .

What is the conservation of energy?

In a closed system, the amount of energy is fixed. You can't create any more energy inside the system or destroy any of the energy that's already in there. But you can convert the energy you have from one form to another (and sometimes back again).

What is a closed system?

Artwork: A closed system?

Examples of the conservation of energy

Where does your fuel go?

Artwork: Figures for city driving from Where the energy goes , fueleconomy.gov.

Photo: An electric kettle like this converts electrical energy into heat energy. That's the reverse of the process that happens in the power plant that supplies your home, where electricity is produced using heat energy released by burning a fuel such as coal, oil, or gas.

Pushing a car uphill

Artwork: When you push a car uphill, the potential energy it gains comes from the energy your body loses in the process.

Who discovered the conservation of energy?

“ ... the quantity of heat produced by the friction of bodies, whether solid or liquid, is always proportional to the quantity of force expended. ” James Prescott Joule, The Mechanical Equivalent of Heat, 1845.

Why perpetual motion machines never work

Find out more.

The Museum of Unworkable Devices : An excellent website about perpetual motion machines (and similar unworkable devices) compiled by Donald E. Simanek, former professor of physics at Lockhaven University.

What about the conservation of mass?

If you liked this article..., on this website.

Atomic energy

On other websites

The Mechanical Equivalent of Heat : A good Wikipedia article about James Prescott Joule's famous experiment.
The Conservation of Energy : In this short video clip from his MIT lectures, Professor Walter Lewin demonstrates very impressively that you can't finish up with more energy than you started off with. Luckily for him, as it turns out!

For younger readers

Eyewitness Energy by Jack Challoner and Dan Green. Dorling Kindersley, 2016. A simple introduction to the science, technology, and history of energy. Ages 9–12.
Energy by Chris Woodford. Dorling Kindersley, 2007. My own colorful introduction explains what energy is, where it comes from, and how we use it in our everyday lives. Ages 9–12.
Power and Energy by Chris Woodford. Facts on File. This longer book of mine is a history of human efforts to harness energy, from ancient technologies like water power to the latest forms of renewable energy. Suitable for most readers from about ages 10 upward.

For older readers

Great Experiments in Physics: Firsthand Accounts from Galileo to Einstein by Morris H. Shamos. Dover, 1959/1987. This utterly wonderful book (one of my favorite books ever!) contains reprints of papers reporting many of the greatest physics experiments of all time, including "Chapter 12. The Mechanical Equivalent of Heat" by James Prescott Joule. You may be able to read the whole paper via Google Books if you scroll through to page 166.
Six Easy Pieces by Richard Feynman. Basic Books, 2011. Chapter 4 is a clear, simple, theoretical explanation of the conservation of energy.
How a missing penny explains the conservation of energy by Rhett Allain. Wired, May 2, 2017. There are no missing pennies: the energy books must always balance!
Fact or Fiction?: Energy Can Neither Be Created Nor Destroyed by Clara Moskowitz. Scientific American, August 5, 2014. Can we find anything that violates the most fundamental energy law?
The Discovery of the Law of Conservation of Energy by G. Sarton et al, Isis, Vol. 13, No. 1 (Sep., 1929). This article traces the history of the conservation of energy back through Mayer, Joule, Carnot, and others.
On the Principle of the Conservation of Energy by Ernst Mach, The Monist, Vol. 5, No. 1 (October, 1894), pp. 22–54 (33 pages). Mach discusses the broader signifance of the law and in terms of our concepts of energy.
Conservation of energy in the human body , Scientific American, Vol. 81, No. 6, August 5, 1899.

References ↑ Five medium ripe bananas contain about 500 calories according to the US Department of Agriculture database. How much energy you use during swimming varies according to stroke and vigor, and what your body's like, but 500 calories is a decent ballpark figure . Richard Muller explains the calculation more generally and notes that an hour's vigorous exercise of any kind burns off roughly 400 calories (I've rounded up) in Physics and Technology for Future Presidents (Princeton: Princeton University Press, 2008. p.26) ↑ I cover this story in my book Atoms Under the Floorboards , p.38. It's covered at greater length in James Joule, Letter to the editors, Philosophical Magazine 27 (1845): 205, quoted in Shamos, M. H. (ed.) (1987), Great Experiments in Physics (Dover, New York), p. 169. Please do NOT copy our articles onto blogs and other websites Articles from this website are registered at the US Copyright Office. Copying or otherwise using registered works without permission, removing this or other copyright notices, and/or infringing related rights could make you liable to severe civil or criminal penalties. Text copyright © Chris Woodford 2012, 2021. All rights reserved. Full copyright notice and terms of use . Follow us

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Essay on Energy Conservation

Energy is all around us, and it’s what makes our world work. From the lights in our homes to the cars on the road, energy is essential for our daily lives. However, it’s important to remember that energy is not an infinite resource. We need to use it wisely and conserve it for the future. This is where energy conservation comes into play. In this essay, I will argue that energy conservation is crucial for a sustainable and bright future.

What is Energy Conservation?

Energy conservation means using less energy to do the same tasks. It involves finding ways to reduce our energy consumption while still meeting our needs. For example, turning off lights when we leave a room, using energy-efficient appliances, and insulating our homes to keep them warm in the winter and cool in the summer are all ways to conserve energy. By doing these things, we can save money on our energy bills and help protect the environment.

Why is Energy Conservation Important?

Energy conservation is essential for several reasons. First and foremost, it helps reduce our impact on the environment. When we use less energy, we produce fewer greenhouse gases, which are responsible for climate change. By conserving energy, we can slow down the warming of the Earth and protect our planet for future generations.

Secondly, energy conservation can save us money. When we use less energy, our energy bills go down. Imagine if you could save money every month just by being more mindful of how you use energy! That extra money can be used for other important things, like education, healthcare, or fun activities with your family.

How Can We Conserve Energy?

There are many simple ways we can conserve energy in our everyday lives. One way is to use energy-efficient light bulbs. These bulbs use less electricity and last longer, which means we save money and reduce our energy consumption. Another way is to unplug electronic devices when we’re not using them, like chargers, computers, and TVs. Even when these devices are turned off, they can still use energy if they’re plugged in.

Additionally, we can save energy by using public transportation or carpooling instead of driving alone in our cars. When we drive less, we use less gasoline, which helps reduce air pollution and save money on fuel. Moreover, we can turn off the tap while brushing our teeth to save water heating energy and make sure our homes are well-insulated to keep the heat or air conditioning inside.

The Impact of Energy Conservation

The impact of energy conservation goes beyond just saving money and protecting the environment. It also helps create a more sustainable future. Sustainable means that we can meet our needs today without compromising the ability of future generations to meet their needs. By conserving energy, we ensure that there will be enough energy for everyone in the future.

Imagine a world where there is not enough energy to power our homes, schools, and hospitals. It would be a challenging and uncertain place to live. But if we start conserving energy now, we can avoid that future and make sure that energy is available for everyone, now and in the years to come.

Conclusion of Essay on Energy Conservation

In conclusion, energy conservation is not just a good idea; it’s a crucial step toward a better future. It helps us reduce our impact on the environment, save money, and ensure that there will be enough energy for everyone in the future. We can all do our part to conserve energy by making small changes in our daily lives, like using energy-efficient light bulbs and turning off devices when we’re not using them.

So, let’s work together to conserve energy and create a more sustainable and brighter future for ourselves and the generations to come. By doing so, we can enjoy the benefits of energy conservation and make our world a better place for everyone.

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High school physics - NGSS

Course: high school physics - ngss > unit 3.

What is energy?
Law of conservation of energy
Understand: introduction to energy

Energy Use and Conservation Essay

Introduction, energy consumption, environmental law.

Energy consumption is an important concern in the current world; this is due to the dwindling energy resources globally. As a result, leaders and the global population have initiated measures on adopting green energy as a means of conserving the energy reserves.

A major concern of environmentalists and leaders is global warming and due to these concerns, state governments are adopting cleaner and better energy sources for the global population. This essay is going to analyze my energy use while I analyze the steps that I could take in minimizing environmental damage by reducing my energy consumption.

Based on the chart above, most of my energy use is derived from the use of natural gas and electricity. Due to the changes in the sourcing of energy I decided to make use of solar heating especially in showering and cooling my house. I make use of electricity for lighting in the house and for use on devices like computers and television for recreational activities.

The electricity company that supplies my electricity produces its electricity from nuclear sources; this information was sourced from the California energy commission. Most of the energy supplied in California is nuclear energy (Winteringham, 2009).

As a measure of decreasing my energy use, I think purchasing devices which consume less energy, providing more lighting to avoid misuse of electricity and reduce frequency of tasks which require energy such as cooking. Energy efficiency depends on the utilization of energy in a proper manner; in my case I would increase energy efficiency by redesigning my house to allow for more ventilation thus less electricity is used in cooling (Jakab, 2008).

Another strategy would to use solar energy in cooking and thus this could replace gas and increase efficiency. By making use of renewable energy I am able to save on costs and thus increase on general energy efficiency. My opinion of importing oil from Russia is a good idea in the sense that Russia has huge reserves of oil and coal and thus exploiting the dwindling energy resources of the Unites States could be costly and detrimental to the environment (Winteringham, 2009).

The current environmental debate going on in the state of California where I reside is the removal of the moratoria placed on oil drilling the coast of California. The debate was ignited by the recent activities of the oil spill off the east coast of the United States. Oil spills are costly to the environmental since the cause major ecological damages (Bender, 2006).

According to economists and environmentalists, the moratoria should be lifted to allow for oil exploration along the Californian coast since safety standards in oil mining has been enhanced. However, I oppose this move since oil exploration usually leads to ecological damage that cannot be quantified in the event of an oil spill or lack of proper exploration. Ecological damage is more costly than exploring/mining cheap oil (Bender, 2006).

Energy use and conservation has been debated recently as the demand to energy rises and thus causing a problem for the global climate. Thus the right to clan and cheap energy has been a tough burden to meet by governments, companies or individuals.

In tackling this problem measures need to put in place through engagement of energy users such home owners, industrialists and other in conserving energy though use of renewable and sustainable energy. The essay has looked into an individual way of suing energy and means of achieving energy efficiency in the home.

Bender, M. (2006). California environmental law reporter. Los Angeles, CA: Matthew Bender.

Jakab, C. (2008). Energy Use. San Francisco, CA: Black Rabbit Books.

Winteringham, F. (2009). Energy use and the environment. Boston, MA: Lewis Publishers.

Effects of Oil Spills on Aquatic Environments
The Oil Spill in the Gulf
Effect of Oil Spills on Seafood
United National Environment Programme (UNEP)
Steps by the Local and Military Officials to Prevent the Spread of Avian Flu in Okiwan
Water Pollution and Wind Energy
Evolution of Solar Energy in US
Bio Desertification and Environmental Issues in Eritrea
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IvyPanda. (2018, October 17). Energy Use and Conservation. https://ivypanda.com/essays/energy-use/

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Energy Sustainability with a Focus on Environmental Perspectives

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Published: 22 April 2021
Volume 5 , pages 217–230, ( 2021 )

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Energy sustainability is a key consideration for anthropogenic activity and the development of societies, and more broadly, civilization. In this article, energy sustainability is described and examined, as are methods and technologies that can help enhance it. As a key component of sustainability, the significance and importance of energy sustainability becomes clear. Requirements to enhance energy sustainability are described, including low environmental and ecological impacts, sustainable energy resources and complementary energy carriers, high efficiencies, and various other factors. The latter are predominantly non-technical, and include living standards, societal acceptability and equity. The outcomes and results are anticipated to inform and educate about energy sustainability, to provide an impetus to greater energy sustainability.

Cost, environmental impact, and resilience of renewable energy under a changing climate: a review

The costs and benefits of environmental sustainability

Circular economy strategies for combating climate change and other environmental issues

Avoid common mistakes on your manuscript.

1 Introduction

Energy is utilized pervasively to provide energy services of all types. These include the provision of electricity, transportation, lighting, heating, cooling, industrial processes (e.g., refining and manufacturing) and many more. The full life cycle of energy is complex, and includes obtaining energy sources, converting them to useful forms, transporting, distributing, storing energy, and utilizing energy (Karunathilake et al. 2019 ). The services provided by energy allow for good living standards and support societal development.

Most countries today use energy in a manner that is not sustainable (Baleta et al. 2019 ). This applies to countries of all kinds (developing, industrialized, etc.) (Kumar and Majid 2020 ). Despite this general view, it is observed that wealthy countries appear to be using energy in a manner that is more sustainable today than before 1970. This phenomenon is illustrated in Table 1 . For G7 countries, for instance, energy use per capita and real gross domestic product per capita both rose in step by about 60% between 1960 and 1973, but between 1973 and 2015, energy use per capital remained roughly constant while real gross domestic product per capita continued to rise, by roughly 100% (World Bank Group 2021 ). These data suggest that energy usage and GDP growth per capita became in part decoupled, implying countries can continue to generate wealth without necessarily using increasing amounts of energy through a higher energy intensity. Note that, as the data in Table 1 are just for the G7 countries, the rest of the world may not follow this behavior. G7 countries have outsourced portions of their heavy industry, which tends to be energy intensive, to developing and recently developed countries (e.g., Mexico). Hence, the net effect globally in terms of reducing energy consumption is likely less that that observed for G7 countries.

Energy sustainability involves the use of energy during all aspects of its life cycle in a manner that supports the various facets of sustainable development. Energy sustainability is, therefore, a comprehensive concept that reaches beyond the use of sustainable energy resources, and can be viewed as a component of overall sustainability.

A universally accepted definition for energy sustainability does not exist, even though some definitions have been proposed ( 2017a ; Zvolinschi et al. 2007 ; Chen et al. 2020a ; Razmjoo et al. 2020 ; Suganthi 2020 ; Kumar and Majid 2020 ). A general definition can perhaps be developed by extending definitions of sustainability or sustainable development. For instance, Kutscher et al. ( 2019 ) define sustainable energy as energy produced and used in such a way that it “meets the needs of the present without compromising the ability of future generations to meet their own needs.” Grigoroudis et al. ( 2019 ) suggest that “energy sustainability is related with the provision of adequate, reliable, and affordable energy, in conformity with social and environmental requirements.” Nonetheless, defining energy sustainability is challenging due to the multidisciplinary and complex nature of energy sustainability. The present author defines energy sustainability as the provision of energy services for all people now and in the future in a manner that is sustainable, i.e., adequate to meet basic necessities, not unduly environmentally detrimental, affordable by all, and acceptable to people and their communities. Note that the author’s definition has a temporal persistence element, and that it includes communities, which adds a collective element such as can be represented by culture. Note also that the concept ‘basic necessities’ has an element of vagueness as do other aspects of definitions of energy sustainability or overall sustainability. This can be problematic, although it also provides room for interpretation by individual countries or regions. Since overall sustainability is often viewed as the simultaneous attainment of environmental, economic and societal sustainability, it is clear that energy processes affect each these facets of sustainability. This highlights the importance of energy sustainability to sustainability overall. The relevance of these ideas is increasingly in the fore, as many countries and cities are seeking to become more sustainable, and view energy sustainability as a component of this objective.

Notable environmental, economic and societal challenges are associated with energy. These need to be addressed adequately as part of achieving energy sustainability, although the process can be complex and challenging. Some of the notable challenges relate to societal inequities, excessive resource consumption, climate change and the environmental and ecological affects of other emissions, and limited energy affordability. These are made more challenging by the fact that energy prices are skewed by taxes and incentives, and political factors affect energy issues, sometimes greatly. In addition, wealth and living standards as well as population, culture and level of urbanization often vary among countries, further affecting energy sustainability. The challenges are often greater for developing and non-industrialized countries, due to lack of wealth, education, technology and many other factors. The objective of this article is to assist in addressing these challenges, by informing about energy sustainability and enhancing efforts supporting energy sustainability.

It is noted that this extends earlier work by the author, including an effort to develop a pragmatic approach to energy sustainability with relevant illustrations (Rosen 2009 ). The first illustration considers a thermal energy storage that receives and holds heat (or cold) until it is required, while the second assesses a heat pump that uses electricity to extract heat from a low-temperature region and to deliver it to a region of higher temperature for heating. The third illustration is cogeneration of thermal and electrical energy as well as trigeneration of electricity, heat and cold, while the final illustration considers hydrogen production based on thermochemical water decomposition driven by nuclear or solar energy.

Energy resources are obtained from the environment. Some energy resources are renewable and some are finite in quantity and thus non-renewable. Energy systems in most countries today are principally driven by fossil fuels, but renewable energy utilization is increasing (Karunathilake et al. 2019 ; Hansen et al. 2019 ; Mehrjerdi et al. 2019 ; Kumar and Majid 2020 ). Renewable energy resources are listed with details on the main basis from which they are derived in Table 2 , while non-renewable energy resources grouped by resource type are given in Table 3 . Data from the IEA ( 2020 , 2021 ) on global production of the energy resources are also provided for the most significant resources in terms of quality. It is seen that many types of renewable energy are derived from solar energy, including hydraulic, biomass, wind and geothermal energy (as ground energy at ground temperature) (Rosen and Koohi-Fayegh 2017 ). Constraints on long-term energy supplies help to determine the sustainability of the energy resources and have been discussed by Weisz ( 2004 ).

Energy carriers are the forms of energy that are utilized in processes and systems, and include fuels, electricity and heat (Rosen 2018 ). Some energy carriers exist in the environment while others do not and need to be produced artificially. Energy carriers, divided by energy carrier type, are listed in Table 4 for non-chemical energy carriers and in Table 5 for chemical energy carriers. Note that energy carriers do not include energy storages, which are simply temporary buffers for energy resources or carriers. Energy storages are indeed important and discussed subsequently in the article.

Energy is seen in Tables 2 , 3 , 4 and 5 to exist in various forms. Energy-conversion processes and technologies convert energy from one form to another, and can be described with thermodynamics. Of particular use are the first law of thermodynamics (the principle of conservation of energy) and the second law (the principle of non-conservation of entropy). The latter in particular helps determine energy quality and is the basis for the quantity exergy.

3 Sustainability and Sustainable Development

There are various understandings of sustainability and sustainable development, embodying various viewpoints (Rosen 2018 ; Baleta et al. 2019 ; Hengst et al. 2020 ; Pauliuk 2020 ; Dragicevic 2020 ; Chen et al. 2020a ; Rezaie and Rosen 2020 ). Some of the more significant of these are illustrated in Fig. 1 and examined below (Fig. 2 ):

Selected understandings of sustainability and sustainable development, embodying various viewpoints

Sustainability viewed as having three principal facets: environmental, economic and societal

United Nations Sustainable Development Goals (SDGs) (public domain material provided by United Nations at http://www.un.org/sustainabledevelopment/news/communications-material/ )

Multidisciplinary . Sustainability is often viewed as multidimensional with economic, social and environmental facets (see Fig. 2 ). Achieving sustainability is a challenge as these three facets are often opposing, e.g., economic sustainability may necessitate sacrificing environmental sustainability, and vice versa. Jose and Ramakrishna ( 2021 ) point out the multidisciplinary nature of sustainability in their assessment of the comprehensiveness of research in the field.

Carrying capacity . Sustainability can be considered in terms of carrying capacity, i.e., the maximum population supportable, given the ability of the environment to provide resources and receive wastes. This involves an environmental perspective, but is focused more on limitations. The demand and supply of resources affects carrying capacity significantly. For example, Park et al. ( 2020 ) have evaluated the carrying capacity as a measure of sustainability, for Jeju Island, South Korea.

Temporal . Sustainability is usually understood as temporally lasting. The temporal scale to be considered is subjective, although a period of 50–100 years is fairly often viewed as reasonable for many sustainability considerations (Graedel and Allenby 2010 ). Yet, this time frame can be disputed, especially for energy issues that can straddle centuries or more. For example, the lifetimes in terms of reserve base for fossil fuels have been estimated to be 51 years for oil, 53 years for natural gas and 114 years for coal, based on annual consumption rates (BP 2016 ). Thus coal-burning could be viewed as sustainable for the next 100 years or so based on the available resources, but then they would be practically exhausted clearly making them coal use not sustainable (and that is not considering the pollution and climate change effects from coal combustion). This contrasts with solar and wind energy, which have no date to exhaustion (until the sun ‘dies’ through running out of hydrogen, in about 5 billion years). Clearly, too short a period for evaluating sustainability is not helpful since most activities are sustainable for years, but too long a period is intractable.

Goals . Sustainability can be described in terms of aims or goals. Notable advances have been made in this approach (Rosen 2017c ) with the adoption of the UN Sustainable Development Goals for 2015–2030, which encompass 17 broad goals (see Fig. 3 ) (United Nations 2015 ). Adopted at the 70th Session of the United Nations General Assembly in 2015, the UN Sustainable Development Goals form part of the 2030 Agenda for Sustainable Development. It is noted that work by the United Nations on sustainability has a lengthy history, extending back to the World Commission on Environment and Development ( 1987 ) and its 1987 report ‘Our Common Future,’ which defined sustainable development as ‘development that meets the needs of the present without compromising the ability of future generations to meet their own needs.’

4 Sustainability and Energy

Based on the present author’s definition of energy sustainability cited earlier (the provision of energy services for all people now and in the future in a manner that is adequate to meet basic necessities, not unduly environmentally detrimental, affordable by all, and acceptable to people and their communities), it is evident that various issues impact how energy resources can be sustainable. Many of these issues are illustrated in Fig. 4 . Through these issues, key needs for energy sustainability can be developed. These are listed in Table 6 along with interpretations of them.

Principal issues for achieving or shifting towards energy sustainability

The key needs for energy sustainability are examined in the remainder of this section.

4.1 Low Environmental and Ecological Impacts

Numerous environmental and ecological impacts are associated with energy systems over their lifetimes, ranging from local to national and international. Energy-related environmental and ecological impacts must be adequately addressed to attain energy sustainability, as their mitigation supports energy sustainability (Rosen 2012 , 2018 ; Sciubba 2019 ; Veiga and Romanelli 2020 ).

Some of the more notable environmental and ecological impacts linked to energy are as follows:

Global climate change due to greenhouse gas emissions (Almazroui et al. 2019 ; Scott 2007 ).

Abiotic resource depletion, due to the excessive use of non-biological and non-renewable raw materials (Graedel and Allenby 2010 ).

Acid precipitation and acidification due to emissions of substances such as sulfur dioxide and nitrogen oxides (Rosen 2012 ).

Stratospheric ozone depletion, which allows increased levels of ultraviolet radiation to reach the surface of the earth, causing adverse health effects (Razmjoo et al. 2020 ).

Ecotoxicity and radiological exposures, and the health problems they can cause, such as those due to radioactivity in building materials (Pillai et al. 2017 ).

Climate change, as a consequence of global warming, is caused mainly by emissions of greenhouse gases (especially carbon dioxide), and is particularly concerning due to its potentially severe consequences (loss of land fertility in near equatorial regions, rising ocean levels and flooding of many cities, more frequent and stronger storms, etc.). These effects and others have recently been quantitatively assessed (Chen et al. 2020b ). By disrupting the earth–sun–space energy balance, these emissions lead to increases in mean global temperatures and consequential changes in climates. Low-carbon and carbon-free energy options are needed for climate change mitigation, as they can significantly lower emissions of the primary greenhouse gas, carbon dioxide, which is emitted through carbon fuel combustion.

Many effects of climate change have been studied, such as its impacts on hydro-meteorological variables and water resources (Almazroui and Şen 2020 ) and on water engineering structures (Almazroui et al. 2019 ). In addition, responses to climate change in the form of mitigation efforts have been examined, including carbon sequestration (Were et al. 2019 ) and carbon emission reduction (Khalil et al. 2019 ). Many of the effects and responses mentioned here relate to energy use, directly or indirectly.

For comprehensive and meaningful assessments of environmental and ecological impact, the overall life cycle of an energy system or activity needs to be considered, starting with the harvesting and processing of energy and other resources, and on to their utilization and ultimate disposal. Life cycle assessment (LCA) is an effective methodology for analyses (Graedel and Allenby 2010 ). LCA has been applied extensively to a broad range of activities (Ben-Alon et al. 2019 ; Lodato et al. 2020 ; Lu and Halog 2020 ), including energy processes (Sadeghi et al. 2020 ; Mendecka et al. 2020 ) and communities (Karunathilake et al. 2019 ).

4.2 Sustainable Energy Resources and Complementary Energy Carriers

Sustainable energy resources are crucial to energy sustainability, as are complementary energy carriers that allow those energy resources to be exploited or facilitate sustainable energy options. On the one hand, fossil fuels (see Table 3 ), the most common non-renewable energy resources, are finite in nature. On the other hand, renewable energy sources, including solar, hydraulic, wind, biomass, and geothermal energy (see Table 2 ), can be sustained for extremely long. Renewable energy resources also mitigate greatly or avoid greenhouse gas emissions, among other advantages. Some special cases are worth noting:

Uranium (nuclear energy fuel) is a non-renewable energy resource but it does not contribute significantly to climate change, and the lifetimes of nuclear fuel assuming their use in advanced breeder reactors is thought to exceed 1000 years, so it is often viewed as a sustainable energy option (Al-Zareer et al. 2020a ). For example, Fetter ( 2009 ) estimated the extraction of uranium from seawater would make available 4.5 billion metric tons of uranium, representing a 60,000-year supply at present usage rates, while fuel-recycling fast-breeder reactors could match today’s nuclear output for 30,000 years, based on data of the Nuclear Energy Association (NEA). But this is contentious, as these very long nuclear fuel lifetimes remain hypothetical, while current actual nuclear power plants consume uranium at a much faster rate relative to reserves, in the process generating significant amounts of waste with half-lives that are significantly longer than 1000 years. The supply was estimated at 230 years in 2009 (Fetter 2009 ), based on identified uranium resources of total 5.5 million metric tons and an additional 10.5 million metric tons still undiscovered and the consumption rate at that time. Moreover, only very few nuclear plants are “fast breeder reactors”.

Biomass may or may not be considered a renewable energy option, depending on its rates of utilization and replenishment. Regardless of the classification, decisions on using various types of biomass depend on both their costs (in terms of energy use quantity and rate, net quantity of carbon used, economics), and their benefits (net quantity of carbon emissions avoided, financial savings, etc.). The potential for biomass use to be sustainable often includes energy return on investment (EROI), which is the ratio of the amount of usable energy delivered from a particular energy resource to the amount of energy used to obtain that energy resource (Hall et al. 2014 ; Wang et al. 2021 ). This value has ranged from 0.64 (below the breakeven value of 1) for early biomass uses for producing ethanol to as high as 48 for some particular processes involving molasses, and typical values today are 4–5. Biomass is generally not sustainable when EROI values are near or below 1. In addition, it is noted that biomass typically has a low-energy conversion efficiency (relative to values for fossil fuels) and its production sometimes displaces food production, reducing in those cases its prospects as a sustainable energy resource.

Wastes, which can include some forms of biomass, are sometimes viewed as a renewable energy resource and sometimes are not, given people can modify behaviors to reduce wastes greatly.

Much research on energy resources has been reported, including electricity generation from food waste through anaerobic digestion (Ali et al. 2019 ; Rezaie and Rosen 2020 ) and hydroelectric generation (Udayakumara and Gunawardena 2018 ), and solar energy applications (Hachem-Vermette et al. 2019 ; Sun et al. 2019 ). These studies collectively demonstrate the importance of energy sources in discussions of sustainability, and illustrate the feasibility of such technologies in practical applications.

Energy carriers, which include electricity, thermal energy and secondary fuels (see Tables 4 , 5 ), play an important although less prominent role in energy sustainability. Before they can be utilized, energy resources often require conversion to other energy forms or carriers, e.g., solar photovoltaic panels to produce electricity for renewable energy resources, petroleum refineries for non-renewable energy resources, and hydrogen production from both types of energy resources. The latter example supports the idea of a hydrogen economy, in which hydrogen and electricity are the two main energy carriers (Scott 2007 ; Rosen 2017b ; Gnanapragasam and Rosen 2017 ; Moharamian et al. 2019 ; Abe et al. 2019 ; Endo et al. 2019 ; Fonseca et al. 2019 ; Chapman et al. 2020 ; Al-Zareer et al. 2020a ; Mehrjerdi et al. 2019 ) . Energy sustainability is supported well by this combination of energy carriers since most chemical energy needs can be satisfied by hydrogen (and select hydrogen-derived fuels) and non-chemical energy needs by electricity.

4.3 High Efficiencies

High efficiency in a holistic sense is broad, covering:

high device and system efficiencies,

energy conservation,

energy management and matching of energy demands and supplies,

appropriate utilization of energy quality, and

advantageous fuel substitution.

This holistic sense is adopted here. High efficiency supports energy sustainability by expanding the benefits of energy technologies, whether renewable or not, although the benefits are more pronounced for non-renewable energy resources. High efficiency elongates the lives of finite-energy resources and lowers the capacities needed for energy devices. High efficiencies often can improve societal metrics such as standard of living, quality of life, and satisfaction. For instance, the US and Sweden have similar gross domestic products (per capita), but the latter exceeds the US in most social indicators and utilizes 40% less energy (per capita) through more efficient buildings, smaller automobiles and better public transit, and higher gasoline taxes (Rosen 2018 ). Advanced methods are available to help attain high efficiencies, e.g., exergy analysis provides insights not available via conventional energy methods (Rosen 2012 ; Dincer and Rosen 2021b , 2015 ) and has been applied widely (Morosuk and Tsatsaronis 2019 ; Sciubba 2019 ; Veiga and Romanelli 2020 ; Kumar et al. 2020 ).

4.4 Economic Sustainability and Affordability

Energy sustainability necessitates that the energy services required for basic needs be economically affordable by most if not all people and societies (Rosen 2011 ). However, the economics of energy sustainability measures usually need to be reasonably competitive with conventional approaches to find acceptance and adoption, although it is noted that some efficiency measures, like some environmental impact mitigation measures, can over time sometimes pay for themselves or save money. Government incentives also can enhance affordability.

Of course, many other factors affect economic sustainability and affordability. First, the economic “externalities” associated with fossil fuel combustion, i.e., the environmental costs that are not accounted for in the cost of production, are normally not counted. When externalities are properly accounted for, the economics improve for non-polluting energy forms such as wind and solar, and can become more favorable than the economics for fossil fuels. For example, Bielecki et al. ( 2020 ) show that the costs of externalities for fossil fuels and peat are typically 10–100 times greater than those for sustainable energy forms such as hydraulic, solar, wind, biomass and nuclear. Furthermore, economies of scale are an important factor in lowering economic costs, thereby making energy sources more sustainable. In addition, the economics of energy often fluctuates in response to energy resource scarcity or abundance, political instability for the case of finite-energy resources such as oil, natural gas, and uranium. Finally, the intermittency of some renewable energy forms such as wind and solar can raise their costs.

Other needs exist for energy sustainability and need to be addressed, and a great number of these are non-technical. Selected needs are shown in Fig. 5 and discussed below:

Selected non-technical aspects of energy sustainability

Geographic and intergenerational equity. For energy sustainability, equity is needed among present and future generations and among developed and developing countries in terms of energy access. Being concerned about future generations is important to the temporal aspect of sustainability, and involves considering the responsibility of people to consider the effects of their actions today, and their motivations, on any harm that may be brought to future generations. This involves trade offs. Concerns about energy access developed and developing countries raises issues of fairness and other trade offs, e.g., is it reasonable for countries that became wealthy in large part through extensive use of fossil fuels to ask developing and poorer nations to forego the use of fossil fuels and to use more sustainable energy forms, even if the costs are higher.

Increasing population, energy demands and living standards. Increasing global population must be accounted for in energy sustainability measures and strategies, as it places stresses on the carrying capacity of the planet and the environment. Furthermore, the rising demand and desire for energy resources with increasing wealth, especially as developing countries attain higher living standards, also makes energy sustainability more challenging. Energy sustainability can be assisted by measures involving transformations in lifestyles and reductions in energy demands, although this is usually very challenging in general and especially for policy makers. Behavioral modification requires recognition that present development trends are unsustainable over time. Many of these issues have been studied previously, such as the vulnerability of livelihoods in regions and countries (Qaisrani et al. 2018 ).

Resource and land use. Balances are often necessary to preserve resources and land for the uses for which they are most needed. For instance, land uses for growing biomass for biofuels needs to be appropriately weighed against agriculture needs, flooding large tracts of land needs to be balanced against hydroelectric generation requirements, and ecosystem preservation needs to be balanced against long-distance electrical transmission corridors.

Societal acceptability and involvement. For acceptance of energy sustainability measures, societies and their populations must be informed, involved in decisions, and supportive of them. This normally necessitates thorough consultation, and is particularly important when special or disadvantaged communities are involved, such as some indigenous communities.

Aesthetics and cleanliness. Energy sustainability measures should not degrade unduly the aesthetic appeal and cleanliness of the environment, for societal and other reasons. Even renewable energy resources can be aesthetically problematic, e.g., large solar PV installations and wind farms. Of course, aesthetics are a personal matter and vary from one person to another, sometimes considerably, often making it challenging to find the appropriate trade off.

Health and safety. In strategies and plans for energy sustainability, energy options must be healthy and safe, as evidenced by concerns associated with the COVID-19 pandemic that began in 2019. This issue has spawned much research, e.g., an investigation of the impact of daily weather on the temporal pattern of COVID-19 outbreaks (Gupta et al. 2020 ).

Note that these non-technical factors of energy sustainability are at times interconnected, related and overlapping. Note also that many of the non-technical factors are often addressed if the technical factors discussed previously are addressed suitably. An example: factors such as public acceptability, economics, and equity need to be accounted for when choosing among sustainable energy options. Examining these issues makes it apparent that energy sustainability is politically sensitive, due to the political nature of many of the issues raised in the above points. Even though these points may be recognized already, they are included here for completeness, especially in light of their importance.

5 Methods for Enhancing Energy Sustainability

A selection of energy methods that can help enhance energy sustainability directly or indirectly, shown in Fig. 6 , are now described.

Selected methods for enhancing energy sustainability

Efficiency, loss prevention and waste recovery can all help enhance energy sustainability. Appropriately high-efficiency devices and systems facilitate and contribute to energy sustainability, e.g., heaters, chillers and air conditioners, pumps and compressors, motors and fans, and lighting have higher efficiencies today than in the past, the latter due to more efficient bulbs, lower lighting intensities, task lighting, and lighting occupancy sensors. Efficiency can also be improved by preventing losses, e.g., with better insulation, and by recovering energy wastes, e.g., by waste heat recovery.

Exergy analysis and other advanced tools can support energy sustainability. Thermodynamic performance can be better assessed, improved and optimized with exergy analysis rather than energy analysis, since the former evaluates more meaningful efficiencies and better pinpoints inefficiencies. Based on exergy, a measure of energy usefulness or quality or value (Dincer and Rosen 2021b ), exergy methods have been applied increasingly in recent years (Dincer et al. 2017 ; Moharamian et al. 2019 ). In addition, quality matching of energy supply and demand can also support energy efficiency. It is usually more efficient to supply an energy quality better matched to energy demand instead of supplying an exceedingly high-quality energy form, and thus having a quality mismatch, a result well illustrated with exergy analysis. For example, supplying heating for aquaculture at 20 °C with a natural gas combustor capable of heating to 1000 °C is mismatched compared to using simple solar thermal collectors operating at 40 °C.

Governments can also apply incentives (technically and/or societally directed) and enforcement activities to support energy measures. These can be mandatory or voluntary, depending on circumstances and needs. Modifications to lifestyles and societal structures can also reduce energy use, e.g., shifting North America’s transportation preference to mass transit from automotive, in part by changing energy taxation and environmental restrictions.

6 Technologies for Enhancing Energy Sustainability

Sample energy technologies that can help enhance energy sustainability directly or indirectly, shown in Fig. 7 , are now described. Note that the methods discussed in the prior section are intended to include techniques and approaches for improving energy sustainability, while the technologies covered in this section focus on specific technologies that can be employed to improve energy sustainability. Of course the methods can be applied to technologies, but the focus of the prior section was on methods and techniques.

Selected technologies for enhancing energy sustainability

Utilizing renewable energy sources (e.g., hydraulic, solar, wind, geothermal, biomass, wave, tidal and ocean thermal energy) can contribute to energy sustainability, as they can be sustained for long time periods and have low environmental emissions and impacts. These sources have been extensively investigated, e.g., the amplitudes and phases of tides near power stations (Madah 2020 ) as well as the impacts of potential sea-level rise on tides (Lafta et al. 2020 ). Energy storage can also support energy sustainability, in part by offsetting the intermittency of some renewable energy resources (Krishan and Suhag 2019 ). Energy storage can also store energy until it is economic to deploy, and enhance efficiency and energy management (Al-Zareer et al. 2020b ). There are various types of energy storage (Koohi-Fayegh and Rosen 2020 ), including thermal energy storage (Dincer and Rosen 2021a ), underground storage using borehole heat exchangers (Sliwa et al. 2019 ) and batteries (Al-Zareer et al. 2020b ). Energy storage is increasingly being employed in building and HVAC systems (Dincer and Rosen 2015 ), and in renewable energy systems involving hybrid energy schemes (Rekioua 2020 ) and microgrids (Al-Ghussain et al. 2020 ).

Integrated energy systems, based on renewable and/or non-renewable energy technologies, can enhance energy sustainability and efficiency, e.g., polygeneration systems (Rosen and Koohi-Fayegh 2016 ; Calise et al. 2019 ; Rokni 2020 ; Mendecka et al. 2020 ; Kasaeian et al. 2020 ), and linking separate systems advantageously such as in cascading energy systems (Campana et al. 2019 ; Liu et al. 2020 ; Rokni 2020 ).

Building energy systems can be modified to enhance energy sustainability, e.g., using active systems such as renewable energy resources and passive technologies such as Trombe walls, multiple glazing windows and selective window coatings, daylight harvesting, insulation, weatherstripping and caulking. Note that behavior, culture and lifestyle also can affect the success of energy efficiency measures in buildings, as was illustrated for China (Zhang and Wang 2013 ). Energy sustainability can also be enhanced via district energy systems, in which thermal energy can be generated in heating or cooling facilities, using renewable energy or conventional resources, and transported to users. District energy systems are used in many cities and traverse a wide range of distances (Rosen and Koohi-Fayegh 2016 ). Buildings in many cities are connected through district energy systems that provide space and water heating and space cooling.

7 Illustration

In this illustration, we consider net-positive energy buildings. A net-positive energy building over an average year generates more energy from renewable energy sources than it uses, as shown in Fig. 8 , and can support energy sustainability (Rosen 2015 ; Endo et al. 2019 ; Delavar and Sahebi 2020 ; Tumminia et al. 2020 ; Singh and Das 2020 ). A net-positive energy building uses energy for a variety of tasks and generates energy from various renewable energy resources, and achieves net-positive energy status through advanced design and exploitation of technologies such as advanced automation, controls, component integration, energy storage, lighting and HVAC. One of the main upcoming “other energy uses” for electricity in Fig. 8 will likely be for vehicle energy (e.g., for electric automobiles). Such utilization of energy is likely to prove both cost effective and environmentally friendly. A net-positive energy building generates more electrical plus thermal energy from renewable energy sources than it uses over an average year, as shown in Fig. 9 . Such buildings are net energy generators, rather than net energy users, like most buildings today. Research on net-zero and net-positive energy buildings has been reported (Athienitis and O’Brien 2015 ; Mehrjerdi et al. 2019 ; Sun et al. 2019 ), while the International Energy Agency included an annex on “Towards Net-zero Energy Solar Building” and Canada launched in 2011 the Smart Net-zero Energy Buildings Strategic Research Network ( http://www.solarbuildings.ca ). The net-zero and net-positive energy building concepts can be expanded to include transportation devices that are part of the building (Garmsiri et al. 2016 ; Sun et al. 2019 ) and to net-zero and net-positive energy communities (Rad et al. 2017 ; Hachem-Vermette et al. 2019 ; Karunathilake et al. 2019 ; Nematchoua et al. 2021 ).

Net-positive energy building, in which energy generation from renewable energy resources exceeds energy use over a typical year

Imbalance of a net-positive energy building, highlighting how energy use over a typical year is less than energy generation from renewable energy resources

As a numerical example that correlates with the qualitative presentation in Fig. 8 , a performance assessment by Zomer et al. ( 2020 ) of PV systems installed at a positive energy building is considered here. The building is the Fotovoltaica/UFSC solar energy laboratory ( http://www.fotovoltaica.ufsc.br ) in Florianópolis, Brazil (27° S, 48° W). Although originally designed as a zero-energy building with PV systems on rooftops and façades, additional PV systems were installed on the same location on a carport and an electric bus (eBus) shelter and charging station, and ground-mount PV systems with single-axis solar tracking installed. The system then had a peak PV generation capacity of 111 kW. Energy generation and consumption were analyzed on monthly bases, and the key results are listed in Table 7 . The total PV generation in the period could supply 97% of the building (including eBus) energy consumption, accounting for actual performance and downtime for R&D activities. In that case, the building was almost a net-zero energy building (for which the energy supply would meet 100% of the consumption). However, when the systems operate all the time at their optimal performance, the PV system can supply 134% of the building (including eBus) energy consumption, making it a positive energy building.

8 Conclusions

Energy sustainability is described, with a focus on environmental perspectives, as are methods and technologies to enhance it. In essence being a key component of sustainability, the significance and importance of energy sustainability becomes clear. Requirements to increase energy sustainability are discussed, including low environmental and ecological impacts, sustainable energy resources and complementary energy carriers, high efficiencies, low environmental impacts, and various other predominantly non-technical factors. The latter include living standards, societal acceptability and equity. Interrelations among these are examined. Examples and illustrations are described that help to indicate the benefits of enhancing energy sustainability. The illustrations also indicate the complexity of energy sustainability and the factors that contribute to it, showing how challenging it can be to enhance energy sustainability. Net-positive energy buildings in particular illustrate the benefits and challenges. The outcomes and results serve to inform and educate about energy sustainability, to provide an impetus to move people in particular and civilization in general towards it.

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The author is grateful for support provided by the Natural Sciences and Engineering Research Council of Canada, and the contributions of students and colleagues over the years that have helped in developing the ideas presented.

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Energy Conservation Essay in English for Students

January 29, 2022 by Sandeep

Essay on Energy Conservation: Efforts and measures that we take to limit energy consumption are called energy conservation. Renewable energy sources can be replenished back in nature, and Non-renewable sources are not available for unlimited time, and they take millions of years to be regenerated. Our aim should be to reduce, reuse, and recycle available resources. Alternate energy sources like tidal energy, wind energy, and solar energy should be used to conserve energy.

Essay on Energy Conservation in 500 Words

Below we have provided Energy Conservation Essay in English, suitable for class 5, 6, 7, 8, 9 and 10.

Earth provides enough to satisfy every man’s needs, but not every man’s greed. – Mahatma Gandhi

Energy conservation is the act of making an effort to reduce energy consumption. It can be done by either using the power in lesser quantities or using the said energy in more efficient ways. National Energy Conservation Day is celebrated by people all over India on the 14th of December each year. Every year, the world consumes two percent more energy than utilized in the previous year. We are using up more resources than we discover. In India, the domestic sector consumes twenty percent of the energy, whereas the commercial division utilises eighty percent. Around eight percent of the energy is wasted because of the structure and design of the equipment.

Importance of Energy Conservation

Fossil fuels like petroleum, coal, natural gas, and minerals, and metals like iron, silver, gold, copper, etc., are minimal on the earth and exhaustible. Hence, it becomes our social duty to conserve and preserve them. There is a great risk of depletion of non-renewable and limited resources lurking in our heads. Countries like the United States, China, India, etc., heavily depend on oil-producing nations. The stock of oil in these countries is restricted and may come to an end very soon with how people are utilizing it carelessly.

The demand is always more than the supply, and hence, that is why we have to pay such high amounts for this resource. Therefore, it becomes necessary to conserve it and utilize it judiciously until its alternative can be found or discovered. Fossil fuels are a significant contributor to the rise of global warming , and these fuels emit a lot of carbon dioxide into the environment, thus causing the greenhouse effect. The results of global warming are quite evident in how we have been facing rising sea levels, hotter temperatures, and the increase of deadly diseases like cancer.

Hence, conservation of energy is required to reduce the effect of global warming on the planet. Activities like coal mining and building nuclear power plants have caused a lot of forest destruction. This has affected the flora and fauna of those regions in a very negative way. Sometimes, even humans are forcefully displaced from those places. These sites lead to a lot of air pollution and related spills. The only way that we won’t require more of these plants is if we conserve energy wholeheartedly.

Conserving energy can also lead to domestic savings, and it helps us be less dependent on finite resources and use other methods or ways to get things done. For example, one can always use a bicycle to travel to nearby places rather than take their car even to buy groceries from the store at the corner. By conserving energy, we also help in providing better health for ourselves and all other human beings on earth.

Ways and Techniques of Energy Conservation

Some ways of conserving energy are of utmost simple to follow and can be carried out by each individual. You can always make sure that you use electricity only when needed and not waste it. Switch off the lights and fans when not in use. Make it a point to turn off the television if no one is watching it. You can leave curtains open for the direct sunlight to enter during the daytime rather than switching on tube lights. Please turn on your air conditioner for three to four hours at a stretch and then close it during the summers. Please do not keep it running for the whole day or night.

Try doing more tasks manually, rather than taking the help of technology. For example, instead of using the dishwasher, wash dishes with your own hands. Replace the traditional light bulbs in your house with compact fluorescent lights, CFLs, or any other energy-efficient bulbs. These alternatives use twenty-five to eighty percent less electricity than your traditional ones. These can be a little more expensive when you purchase them, but you save a lot on your electricity bills, and they even last at least three times longer.

Certain countries like Singapore, France, Denmark, etc., have started levying an energy tax. This encourages people to use less of it and use it cautiously, forcing them to turn on to less expensive alternatives and inexhaustible. Many institutions, including airports and hotels, have started installing solar panels on their roofs to reduce electricity consumption and channelise the sun’s energy in a way that doesn’t burn a hole in their pockets.

Energy Conservation in the Environment

a detailed description of the problem.

There are so many undefined factors negatively affecting the environment. These are some of the things that make people to put their efforts in protecting the environment. Energy conservation is one of the steps taken towards this and it concerns the global community, the individual countries and local communities. Energy conservation results in general environmental conservation by controlling the use of natural resources. The need to formulate ways as individuals to conserve energy is not well known by many people. Many people always think that such are the responsibilities of the government or environmental conservation movements. There are many overwhelming challenges involved in the process of energy conservation, but it would be a little bit easier if everybody was educated and was able to find ways to cut on the energy they use in the environment. The process of energy conservation involves looking for methods to decrease the mount of energy that is not under use and the one that is usually wasted. This can be accomplished in various ways to ensure that energy is used efficiently and that unnecessary and wasted energy is reduced. There are many advantages that come when energy is conserved and these include helping keep a good environment, cutting costs incurred by businesses and individuals on gas and electricity. “Energy” is defined in physics as the “ability to do work” (Carlini, 2007). Works refers to such activities as warming something, lifting or moving something or lighting. Energy is turned into various forms like heat and power for it to be able to help do work. Energy can be renewable or nonrenewable. The nonrenewable sources of energy are natural energy elements that cannot be reloaded like fossil fuels and coal. Their amounts are usually limited. 71.5% of energy used in the US is from the nonrenewable natural sources (Keith, 2007). Renewable energy sources are like water (hydropower), wind power, energy from vegetation (biomass fermentation), solar energy and geothermal energy. Unfortunately the nonrenewable sources of energy have been used in large and uncontrollable amounts and now they are being depleted. The changes in the climatic and weather trends pose a threat on the availability of our renewable sources of energy. Therefore, the process of energy conservation is a serious issue that should be everyone’s responsibility and it should be treated with the seriousness it deserves.

The living and nonliving factors that contribute to or are affected energy conservation

There are several living and nonliving factors that add to and are affected by energy conservation. Precipitation, temperature, sunlight, water and soil are some of the nonliving factors that affect energy conservation. Sunlight and temperatures both contribute to energy consumption since they both provide us with renewable sources of energy to serve as light and solar power. These are then used instead of non-renewable energy sources. However, water and soil are affected by sunlight and temperatures since high temperature affect the texture of the soil and also reduce the soil water through evaporation. Animals are some of the living factors that could be affected by energy conservation. They could also contribute to energy conservation in one way or another. Carnivores, herbivores and omnivores affect the conservation of energy. Herbivores and the omnivores feed on the plants and this leads to reduction in transpiration because of the reduced vegetation. This in turn affects the amount of rain that the land receives from the transpired water vapor hence reduced hydropower. There are multiplier effects involved in such situations in that there are various effects on the plant life which means that there are few of them to be consumed by the herbivores. The lack of enough food for the herbivores means they can’t stay alive for long and as such the carnivores which depend on them for food will grow weak, sickly and die of hunger as well. The effects on the omnivores like the human beings are inevitable since they lack the plants and other animals to feed on hence they pass on as well.

Positive and negative human impacts

The positive impacts human beings have on energy conservation are; committing a certain amount of money to improve energy efficiency. This is mostly done by the help of government and international organizations. They do this by setting aside some money in their budgets to ensure that alternative energy sources are provided and reduction in energy wastage is achieved. However, the activities of human beings have a negative impact on the process of conserving energy. This is because most people are ignorant of the amount of energy they use. Worse still, they don’t know that if they took a few steps to cut down on their energy use, they could save a lot of energy. Many of them use fluorescent lights in their lamps instead of utilizing the energy saving incandescent lights, or use a 100-watt bulb where a 15-watt bulb can work (Carlini, 2007). If this is done throughout the house of an average American, not only a lot of money but energy could be saved. A person living in a high-rise condo where he is paying a lot of money to the association could ask that fluorescent lights be put in all the common areas in the building. These areas include bathrooms, hallways and locker rooms. This has a great impact on energy conservation and has been done in various shared buildings (Carlini, 2007). Another positive impact humans have on energy conservation is the formulation of various ways to create renewable sources of energy. When renewable sources of energy are used there is no negative impact on the energy conservation because what is used is replaced. However, if human beings rapidly use non renewable sources of energy, it will become hard to retain and sustain them which make the current efforts to conserve them to be in vain. The resources then get depleted which is a threat to human sustainable development.

The gaseous emissions into the air are commonly due to man’s activities and this has very negative impacts on energy conservation. More than 95% of Sulfur oxides and 90% of nitrogen oxides that are released into the atmosphere come from manmade sources (Sustainability City, 2009). Power plants like electricity companies and various industries that utilize coal along with other fossil fuels as energy sources result in a lot of carbon monoxide and sulfur dioxide emitted to the air. Furthermore, the processing of raw ore containing chemical compounds such as sulphides leads to increased emission of sulfur dioxide into the atmosphere. The internal-combustion engines of light trucks and cars which generate energy by burning gasoline release carbon dioxide into the air. When most of these gases go into the air, they result in acid rain and this has a great impact on hydropower in that acid water corrodes the machines used to generate hydroelectric power and energy is not generated. This also adds to instances in greenhouse gases which eventually lead to global warming.

Evaluation of current sustainability strategies and solutions

Currently, there are various strategies put in place by individuals and organizations to reach sustainability. Most of these strategies offer solutions to the problems of energy wastage to ensure that energy is conserved. Various organizations and corporations have put in their efforts to ensure that the world energy consumption is either reduced or conserved. For example the Environmental Protection Agency (EPA) in the United States in conjunction the Boys and Girls clubs in the US together with the parent’s-teachers organizations have purposed to teach the children how to conserve energy. The EPA campaign called the ‘change the world, starts with energy campaign’ encourages the kids and their families to take a pledge entitled the ‘energy star pledge’ that involves using energy saving appliances, cutting wasteful power usage and insulating homes. EPA has confirmed that more than one million Americans have taken the pledge. If the energy star pledge is followed to the letter, the US can save more than $18 billion in one year. This is one of the strategies put toward sustainable development (Rogers, 2001).

Wal-Mart, which is one of the leading dealers in the world, has affirmed that it is the largest electricity consumer in the world. Its new store was launched on January 15 and is termed as the High-Efficiency 2 (HE.2). It saves 20% more energy than the HE.1 Supercenter that was launched a year earlier in Kansas. Most of the electricity conserved is from the new refrigeration loop which is pooled to an advanced water heating, cooling and refrigeration system (Rodgers, 2000). This expertise was tried on stores Wal-Mart and makes use of non-refrigerant answers for cooling the freezers and the refrigerators resulting in more than ninety percent decrease in refrigerant. If these are adopted by most retail stores, departmental stores and superstores, we will attain sustainability as far as energy conservation is concerned. Apart from the strategies used by EPA and the technology at Wal-Mart, there are several other solutions that are being put in place to ensure sustainability. This is the invention of equipment that uses less energy. An example is the Kathabar Dehumidification Systems’ Twin-Cel. This is a liquid desiccant that builds energy reduction by transferring temperature and moisture between streams of air allowing for great energy savings that are more than just a recovery of sensible heat. The increasing technology in the world today is mainly geared towards producing appliances and systems that are efficient and at the same time helping to conserve energy.

Currently there are also strategies to produce electricity using both non- and renewable resources. Hydroelectric power is the one mostly used to generate electricity. There are progresses to ensure that more electricity is produced from solar and wind energy.

The plan to reach Sustainability

I would adopt the plan by the Sustainable City of San Francisco that has four main goals. The first goal is to attain overall power use by maximizing energy efficiency. In this regard, all the citizens have to be educated on issues concerning energy and changes in climate. This will enable them to make informed decisions concerning what impacts their energy choices have on the environment, how they can use energy with efficiency and use of renewables. This will ensure that the electric appliances used by citizens are energy efficient and when they use them, they avoid energy wastage. The second goal is geared towards maintaining an energy supply based on renewable and environmentally friendly sources. The third plan is to ensure that climate-change and ozone layer depletion via emissions and toxins that are associated with energy use and production are eliminated. The final goal is making decisions of energy conservation that are based on the goal of attaining a sustainable society (Sustainability City, 2009).

In line with the mentioned goals, I would also have a personal plan to ensure that as much energy as possible has been conserved. There are so many programs that have been created by the government and nongovernmental organizations like EPA to push the plan of energy conservation forward. Whereas as there are many plans to attain sustainability, none of them can succeed without major investments by governments, organizations and individuals in terms of time and money. That’s why the process of energy conservation has to be planned for in the budgets and in our time schedules. There are also plans to initiate sustainability locally, nationally and internationally. These have been evaluated and found to be successful within the plans and the means that have been decided upon either by the local leadership, national or international community. This could be better however; if it had been coupled with mitigation plans against global warming that would be implemented world wide.

Benefits and challenges of the plan

The mitigation plan for energy conservation definitely has benefits as well as challenges. The plan to have everybody educated on the issues of environmental change and conservation of energy has benefits because it will ease the process of energy conservation in that the people will be reading from the same script. They will understand each and every aspect concerning the conservation of energy. To have everybody use energy maximally and efficiently will to a great extent save a lot of energy. However, this can pose a challenge since people’s standards of living are different and they have different preferences as far as their as appliances are concerned. In addition to this, energy saving appliances are usually very expensive and some people cannot be able to afford them. Total reliance on renewable sources of energy has many benefits in that the sources of energy are always renewed and reloaded. Therefore the threat of running out of the energy is not there. These sources are always very friendly to the environment. The air will be clean and the problem of global warming could be prevented. Emission of dangerous gases to the atmosphere is not possible when renewable sources of energy are used. The problem of acid rain coupled to global warming can be mitigated with the use of renewable sources of energy. While these are apparent advantages of plans to use renewable and environmental friendly sources of power, some organizations will advocate against total reliance on renewable sources of energy. They claim that renewable sources of energy cannot meet all the energy needs of the world. This is true; therefore, it poses a great challenge to total reliance on renewable sources of energy. This then will mean continued use of nonrenewable sources of energy that emit gases to the atmosphere. The plan to eliminate climate change and depletion of the ozone layer from these emissions will also be a challenge. The best that can be done is to decrease the emission of these gases to the environment. Making decisions based on creating a sustainable society is a great plan that will ensure people live in harmony with their society and that the energy available will always be there in plenty to meet the needs of the world. However, there is a challenge to this because times change and economies change. The development of new technologies leads to greater machines that require more energy and power. There is also the increase in population. The world will be so populated that it will need more energy than it needs now. In addition to this, most of the things are going to be automated with things like robots being used in houses instead of house helps and various other machines geared towards making life easy. All these will need more and more energy to sustain the population. Therefore, attainment of sustainability has a great challenge to meet.

Required government, societal, and global support

To ensure sustainability, the government has formulated several policies to decrease energy conservation costs but such laws only apply to large scale corporations, builders and constructors. There should be a change in the taxation system so that individuals can benefit from the tax savings that will encourage them to use the energy saving techniques. This requires the support of the law makers all over the world. The government is also required to create lesson sessions and classes to the public through the local government to ensure information about the importance and the necessity of energy conservation is available to the public. The government is also asked to formulate policies that when implemented, will ensure that factories do not pump dangerous levels of toxic gases in to the atmosphere. This could be done through continuous inspection of the factories to determine those that are exceeding the set limit. This could be done by an independent specialist in pollution who then will recommend the fining of the companies that will be found committing the felony. Renewable sources of energy should be used by all countries and communities worldwide. This cannot be a one man show. All governments are needed and all the societies should be involved to ensure that sustainability is well achieved. They are also required to support the advertising campaigns that should be staged globally to make the world know the hazards of polluting air and wasting energy. The adverts should be in form of adverts in papers, gazette issues done by the different governments, bill boards, television and radio adverts. All these should convey a massage that energy conservation is a must and it should be everyone’s responsibility.

Concluding remarks

The question to whether sustainability will ever be attained in the world cannot be answered. However, the faster and the much we can conserve our energy, the better we can handle the uncertainty. By decreasing greenhouses gases and putting energy conservation plans in place we can attain whatever we are fighting for, no matter how long it will take.

Reference List

Carlini, J. (2007). Energy conservation might take us farther than renewable fuels . Web.

Keith, R. (2007). A Sustainable Energy Plan for Barbados?

Rogers, A. (2000). ‘Teaching Kids to Conserve.’ The Green Gazette, Mother Earth News. Ogden Publishing.

Sustainability City. (2009). Sustainability Plan / Energy, Climate Change and Ozone Depletion / Strategy.

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Energy and Types of Energy

Energy is a universal term we use a lot in our daily life. Although used loosely quite often, energy has a specific physical meaning. In physics, we define energy as the ability of something to do work. Energy can exist in many forms. All forms of energy are either kinetic or potential. In this article, let us understand what energy is and the different types of energy in detail.

What Is Energy?

There are different forms of energy on earth. The sun is considered the elemental form of energy on earth. In physics, energy is considered a quantitative property that can be transferred from an object to perform work. Hence, we can define energy as the strength to do any kind of physical activity. Thus, in simple words, we can define energy as,

Energy is the ability to do work

According to the laws of conservation of energy, “ energy can neither be created nor destroyed but can only be converted from one form to another”. The SI unit of energy is Joule.

Units of Energy

The International System of Units of measurement of energy is joule . The unit of energy is named after James Prescott Joule. Joule is a derived unit equal to the energy expended in applying a force of one newton through a distance of one meter . However, energy is also expressed in many other units not part of the SI, such as ergs, calories, British Thermal Units, kilowatt-hours, and kilocalories, which require a conversion factor when expressed in SI units.

Different Types of Energy

Although there are many forms of energy, it is broadly categorized into:

Kinetic Energy
Potential Energy

Kinetic Energy

Kinetic energy is the energy associated with the object’s motion. Objects in motion are capable of causing a change or are capable of doing work. To better understand, let us think of a wrecking ball. A wrecking ball in motion is used to do work such as the demolition of buildings, stones, etc. Even a slow-moving wrecking ball is capable of causing a lot of damage to another object, such as an empty house. However, a wrecking ball that is not in motion does not do any work. Another example of kinetic energy is the energy associated with the constant, random bouncing of atoms or molecules. This is also known as thermal energy. The average thermal energy of a group of molecules is what we call temperature, and when thermal energy is transferred between two objects, it’s known as heat.

Different Types of Kinetic Energy:

Radiant energy.

Radiant energy is the type of energy that travels by waves or particles. This energy is created through electromagnetic waves and is most commonly experienced by humans in the form of heat. Following are a few examples of radiant energy:
When you turn on an incandescent light bulb, it gives off two forms of energy. There is visible light and heat that is generated. Both these generated energies are a form of radiant energy.
Sunlight is an example of radiant energy.

Thermal Energy

Thermal energy is similar to radiant energy and is experienced in the form of heat or warmth. While radiant energy refers to waves or particles, thermal energy describes the activity level among the atoms and molecules in an object. This is the only difference between radiant energy and thermal energy. Some examples of thermal energy include:

The geothermal energy that comes from the decay of natural minerals and the volcanic action of the earth is an example of thermal energy.
When you heat up the pizza in the oven, you raise the pizza’s temperature. The molecules that make up the pizza move more quickly when the pizza is piping hot.
The warmth you feel emanating from the engine is an example of thermal energy.

Sound Energy

Humans experience the vibrations that reach the human ear as sound. The disturbance moves in the form of waves through a medium like air and reaches our eardrum. On reaching the eardrum, these vibrations are converted into electrical signals and sent to the brain, which we interpret as the sensation of sound.

Electrical Energy

The flow of negatively charged electrons around a circuit results in electricity which we more commonly refer to as electrical energy.

Mechanical Energy

Mechanical energy is the energy associated with the mechanical movement of objects. This type of energy can also be referred to as motion energy.

Potential energy is the energy stored in an object or system of objects. Potential energy can transform into a more obvious form of kinetic energy.

Both potential energy and kinetic energy form mechanical energy.

Different Types Of Potential Energy

Gravitational potential energy.

Gravitational potential energy is the energy stored in an object due to its vertical position or height. A book on a high bookshelf has a higher gravitational potential energy than a book on the bottom bookshelf.

Gravitational Potential Energy Examples

River water at the top of a waterfall
A book on a table before it falls
A car that is parked at the top of a hill

Gravitational Potential Energy – Video Lecture

Elastic Potential Energy

Elastic potential energy is stored as a result of applying a force to deform an elastic object. The energy is stored until the force is removed and the object springs back to its original shape, doing work in the process. The deformation could involve compressing, stretching or twisting the object.

Elastic Potential Energy Examples

A spring that is coiled
The string of an archer’s bow is pulled back
Rubber band that has been stretched

Chemical Potential Energy

Chemical potential energy is the energy stored in the chemical bonds of the substance. The energy can be absorbed and released due to a change in the particle number of the given species.

Chemical Potential Energy Examples

Before the sun shines on the green leaves (potential photosynthesis)
Gasoline before it is ignited
Fireworks before they are launched

Electric Potential Energy

Electric potential energy is the energy that is needed to move a charge against an electric field.

Electric Potential Energy Examples

An incandescent light bulb that is turned off
A radio tower that is not working
A black-light turned off
A television before it is turned on

Energy Conversion: Transfer and Transform

We know energy can be transferred from one form to another. The movement of energy from one location to another is known as energy transfer. We notice various energy transformations happening around us.

Following are the four ways through which energy can be transferred:

Mechanically – By the action of force
Electrically – Electrically
By Radiation – By Light waves or Sound waves
By Heating – By conduction, convection, or radiation

The process which results in the energy changing from one form to another is known as energy transformation. While energy can be transformed or transferred, the total amount of energy does not change – this is called energy conservation.

Law of Conservation of Energy

The law of energy conservation is one of physics’s basic laws. It governs the microscopic motion of individual atoms in a chemical reaction. The law of conservation of energy states that “ In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved .” According to the law, the total energy in a system is conserved even though energy transformation occurs. Energy can neither be created nor destroyed, it can only be converted from one form to another.

Read More: Law of Conservation of Energy

Video Lecture on Kinetic Energy and Potential Energy

Frequently Asked Questions – FAQs

What happens to the total energy of the object falling freely towards the ground, what happens to the energy of a body on which work is done.

The body gains more energy.

What is the commercial unit of energy?

The commercial unit of energy is Kilowatt-hour.

Can energy be stored?

Which of the following is the energy possessed by its position, watch the video and solve ncert exercise questions in the chapter work and energy class 9.

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Energy Conservation Essay for Students and Children
500 Words Energy Conservation Essay. Energy conservation refers to the efforts made to reduce the consumption of energy. The energy on Earth is not in unlimited supply. Furthermore, energy can take plenty of time to regenerate. This certainly makes it essential to conserve energy.
Energy Conservation Essay in English
Here are some sample essays on energy conservation. 100 Words Essay On Energy Conservation. Conservation is an important factor in maintaining the balance of life on earth. Human lives and industries depend on energy, so conservation is necessary for the continued existence of mankind. Furthermore, energy conservation promotes sustainable ...
Energy Conservation Essay
Energy Conservation Essay: Conservation of energy is an essential aspect of human existence. Without conserving energy, there is no way in which can survive in the future. One might wonder why conservation of energy is vital for survival. The reason lies in the renewable and non-renewable resources. All the resources of a country get utilized ...
Conservation Of Energy
An example of a real-life application that explains the law of conservation of energy is cross-country skiing that involves gravitational force. The skier has to overcome gravitational forces in order to move up the hill. During skiing, kinetic energy is transformed to potential energy and vice versa. When a skier is at the bottom and in motion ...
What is conservation of energy? (article)
Energy, as we'll be discussing it in this article, refers to the total energy of a system. As objects move around over time, the energy associated with them—e.g., kinetic, gravitational potential, heat —might change forms, but if energy is conserved, then the total will remain the same. Conservation of energy applies only to isolated systems.
4 Conservation of Energy
To illustrate the ideas and the kind of reasoning that might be used in theoretical physics, we shall now examine one of the most basic laws of physics, the conservation of energy. There is a fact, or if you wish, a law, governing all natural phenomena that are known to date. There is no known exception to this law—it is exact so far as we ...
Energy conservation
Energy conservation is the effort to reduce wasteful energy consumption by using fewer energy services. This can be done by using energy more effectively (using less energy for continuous service) or changing one's behavior to use less service (for example, by driving less). Energy conservation can be achieved through efficient energy use ...
Conservation of energy
conservation of energy, principle of physics according to which the energy of interacting bodies or particles in a closed system remains constant. The first kind of energy to be recognized was kinetic energy, or energy of motion.In certain particle collisions, called elastic, the sum of the kinetic energy of the particles before collision is equal to the sum of the kinetic energy of the ...
7.6: Conservation of Energy
Then we can state the conservation of energy in equation form as. KEi + PEi +Wnc + OEi = KEf + PEf + OEf. (7.6.1) (7.6.1) K E i + P E i + W n c + O E i = K E f + P E f + O E f. All types of energy and work can be included in this very general statement of conservation of energy.
7.6 Conservation of Energy
Law of Conservation of Energy. Energy, as we have noted, is conserved, making it one of the most important physical quantities in nature. The law of conservation of energy can be stated as follows: Total energy is constant in any process. It may change in form or be transferred from one system to another, but the total remains the same.
The law of conservation of energy: A simple introduction
The first thing we need to note is that the law of conservation of energy is completely different from energy conservation. Energy conservation means saving energy through such things as ... 1959/1987. This utterly wonderful book (one of my favorite books ever!) contains reprints of papers reporting many of the greatest physics experiments of ...
Essay on Energy Conservation
Energy conservation is essential for several reasons. First and foremost, it helps reduce our impact on the environment. When we use less energy, we produce fewer greenhouse gases, which are responsible for climate change. By conserving energy, we can slow down the warming of the Earth and protect our planet for future generations.
Conservation of energy
The law of conservation of energy states that the total energy of an isolated system remains constant; it is said to be conserved over time. In the case of a closed system the principle says that the total amount of energy within the system can only be changed through energy entering or leaving the system. Energy can neither be created nor destroyed; rather, it can only be transformed or ...
Law of conservation of energy (video)
The final kinetic energy is the same as the work done as long as the initial velocity is 0m/s. To get a more general answer, we can substitute the expression for the final velocity (√ (v0²+2aΔx)) into the kinetic energy equation Ek=½mv² to get Ek=½m√ (v0²+2aΔx)². This simplifies to get Ek=½m (v0²+2aΔx)
Energy Use and Conservation
Introduction. Energy consumption is an important concern in the current world; this is due to the dwindling energy resources globally. As a result, leaders and the global population have initiated measures on adopting green energy as a means of conserving the energy reserves. We will write a custom essay on your topic.
conservation of energy
The conservation of energy in a physical system can be illustrated by changes in the mechanical energy of a falling object. Mechanical energy consists of two types of energy: potential, or stored energy, and kinetic energy, the energy of motion. Put another way, the total amount of mechanical energy in an object is the sum of its potential and ...
Energy Sustainability with a Focus on Environmental Perspectives
Energy sustainability is a key consideration for anthropogenic activity and the development of societies, and more broadly, civilization. In this article, energy sustainability is described and examined, as are methods and technologies that can help enhance it. As a key component of sustainability, the significance and importance of energy sustainability becomes clear. Requirements to enhance ...
Law of Conservation of Energy
The law of conservation of energy states that energy can neither be created nor be destroyed. Although, it may be transformed from one form to another. If you take all forms of energy into account, the total energy of an isolated system always remains constant. All the forms of energy follow the law of conservation of energy. In brief, the law ...
Full article: A review of renewable energy sources, sustainability
The word "direct" solar energy refers to the energy base for those renewable energy source technologies that draw on the Sun's energy directly. Some renewable technologies, such as wind and ocean thermal, use solar energy after it has been absorbed on the earth and converted to the other forms.
Energy Conservation Essay in English for Students
Energy conservation is the act of making an effort to reduce energy consumption. It can be done by either using the power in lesser quantities or using the said energy in more efficient ways. National Energy Conservation Day is celebrated by people all over India on the 14th of December each year. Every year, the world consumes two percent more ...
Energy Conservation in the Environment
Carnivores, herbivores and omnivores affect the conservation of energy. Herbivores and the omnivores feed on the plants and this leads to reduction in transpiration because of the reduced vegetation. This in turn affects the amount of rain that the land receives from the transpired water vapor hence reduced hydropower.
Energy Conservation
Energy conservation is the act of reducing the usage and wastage of energy. Switching off the AC, light, etc., when nobody is in the room are a few practices that help in energy conservation. We know energy is a broad term and is the fundamental source of living. Energy is classified into various types depending on its nature. Energy ...
The perceived ethicality of promoting employee workplace energy
Results from survey data (N = 200) indicate that promoting workplace energy conservation through a competitiveness message leads to a lower perceived ethicality of message than via a control message. Also, the competitiveness message did not significantly affect employees' behavioural intention towards workplace energy conservation.
Energy- Types of energy, Law of Conservation of Energy, Energy Conversion
Law of Conservation of Energy. The law of energy conservation is one of physics's basic laws. It governs the microscopic motion of individual atoms in a chemical reaction. The law of conservation of energy states that " In a closed system, i.e., a system that is isolated from its surroundings, the total energy of the system is conserved .".

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4 Conservation of Energy

4–1 What is energy?

4–2 Gravitational potential energy

4–3 Kinetic energy

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7.6: Conservation of Energy

Other Forms of Energy than Mechanical Energy

Some of the Many Forms of Energy

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