Energy Conservation| Energy Resources and Consumption| AP Environmental Science| Khan Academy

In this video, we're going to talk about energy conservation, or trying to save or lower the amount of energy that we use. Now, a lot of y'all might already have a sense that that is a good thing, while others of you might say, "Hey, why can't I just use as much energy as possible? Why should I try to use less energy?"

There's several answers to that question. The number one reason is energy has a huge impact on the environment. Most of the energy we produce, and we'll talk about that in a little bit, has the byproduct of emitting greenhouse gases, which are contributing to global warming. On top of that, it has implications for society, the infrastructure around us, and it has, frankly, impacts on you and your family's pocketbooks because energy costs money.

So, let's first think about the household. This chart right over here, which is from the U.S. Energy Information Administration, says residential site electricity consumption by end use. I want to stress that it says electricity consumption because electricity consumption is not the only energy consumption in a household. Depending on where you are, it might be around 50 or 60 percent of consumption, but natural gas is another major source, and in some cases, even petroleum.

When you look over here, the major uses of energy in a household are air conditioning, and that's going to be especially pronounced if you live in a hot and humid part of the country or part of the world. You have space heating, which is what most of us associate with heaters, and then you have water heating. Many of y'all probably don't appreciate when you take those long hot showers that it took energy to warm up that water. Then you have lighting, and you have appliances after that.

So, as you, as an individual, want to conserve energy, it makes a lot of sense to look at things like this. If you want to conserve energy at home, use less air conditioning if you can, use less heating if you can, take shorter showers, or maybe not as hot showers. Showers not only have the energy consumption from heating the water, but it also has energy consumption that's happening at the water treatment plant to clean your water and to process your water. That also takes energy.

Right over here is a refrigerator, and if you have an older refrigerator or a less efficient refrigerator, that's going to use a lot more energy to do the same work. Once again, it's not just the impact on the climate: it's going to save you and your family money by using less energy. But, as we'll see, energy consumption is not just a phenomenon inside of the house.

What we see here is U.S. energy consumption by source and sector in 2020, and this is a little bit of a complex diagram. But it's telling us a lot of information here. On the left, it tells us our sources of energy. So, 35 percent of the energy in the United States comes from petroleum, then 34 percent from natural gas, then 12 from renewable energy—that would be things like wind power or solar power—then you have 10 percent from coal and 9 from nuclear.

Not only does this tell us where the energy is coming from, but it's telling us how it is being used. We could see 36 percent in the industrial sector, so that's all of the factories, the manufacturing that produces all of the goods and services and raw materials that we have in society. 35 percent of our energy in the United States is used for transportation—moving things around, moving ourselves around, but also moving stuff around.

Then, 17 percent is residential, and 12 percent is commercial. This would be things like the energy that the shopping mall is using or the energy that's being used in an office building. This little gray and black box down here is interesting because it shows the role of electricity in this whole scheme. Sometimes something like petroleum might be directly used by, say, an industrial user, but sometimes that petroleum is then used for electricity generation, which can then be used by these various sectors.

Similarly, something like coal could be used directly, or it could be used to produce electricity. Now, one of the eye-popping things that I didn't appreciate until I saw this diagram are the electrical system energy losses. Roughly 65 percent of the energy is lost. If you have a more efficient electrical grid or we know when to produce the electricity, so it more matches up with the demand, then we can once again conserve energy as a society.

That's why it's important to realize some people think, "Hey, if I'm using electricity or if I'm using an electric car that maybe has less impact on the environment." Well, it depends where that electricity is coming from. An electric car actually gives us the option of not necessarily using petroleum. It gives us the option of potentially using renewable energy or nuclear energy. However, that electricity could be coming from things that significantly impact the environment.

When you generally look at this, it tells us that as a society, we have to think about things like investing in public transportation so that we conserve energy there. This right over here is a cement plant. Are there ways to produce these things that are more efficient, that use less energy? There are regulations that might motivate us as individuals to say carpool or drive electric cars, which once again aren't necessarily going to be clean. It depends where that electricity comes from, but it gives us the option of using renewable sources.

So, I'll leave you there. Energy conservation is a complex topic, but a very, very, very important one. Hopefully, this gives you a start on how you can look at how energy is being used in the world, where it comes from, and how you can make a change, both at the personal level right over here and as a member of our democracy at the societal level.