Everything you need to know about energy

So what’s great about fossil fuel energy? The best thing is, it’s easy. You just have to get this stuff out of the ground and burn it. It’s like instant energy just waiting for humans to use it. Most forms of fossil fuels also have high energy density. There is quite a bit of energy in gasoline, which has an energy density of 46.4 MJ / kg. Even if an automobile is only 25% efficient, a single kilogram of gasoline can give you 11.6 million joules of energy. Remember, it took 10 joules to lift a manual off the floor and onto a table. That’s why you can get a car to go 20 to 50 miles on just one gallon of gasoline. You have to admit, this is really impressive.

OK, so what’s not great about fossil fuels? Hope you already know the answer to this question. When you burn a fossil fuel, you produce carbon dioxide. Carbon dioxide is a greenhouse gas and it contributes to climate change. If we continue to burn fossil fuels, the increase in carbon dioxide will change the climate in a way that will make it difficult for humans to continue doing things that we have always done – like living near the coast or doing grow crops in some areas. So that’s what’s wrong with fossil fuels.

But let me be clear. It’s not just the use of gasoline in automobiles. We also burn fossil fuels for the production of electrical energy for use in homes and the like. The basic idea is to burn fossil fuel to heat water and convert it to steam. This steam then pushes on the blades of an electric turbine to turn it. These rotating turbines create electrical energy through electromagnetic interaction (using loops of wires and magnets). A number of energy sources use rotating turbines.

Solar energy

If you just go out on a sunny day, you can feel it. You can feel your body warming up due to the interaction with the sunlight. In fact, at our location in the solar system, the sun gives us about 1000 watts per square meter of energy. Of course, the trick is to get that energy into something more useful like electrical energy. One way to do this is to use a solar panel (photovoltaic cell). It is basically a semiconductor device (with no moving parts) where light can cause a transition of electronic energy to produce electric current. Yes, that’s an oversimplification, but you get the idea. It transforms light energy into electrical energy.

But wait! There is another way to use solar energy. This is called a concentrating solar power plant. The idea is to organize a bunch of mirrors to all reflect the sunlight to a central point. The object at that solar focal point will then get extremely hot, and you can use that hot thing to heat the water to produce steam, and then spin an electric turbine. Oh, usually the extremely hot thing will be a liquid – maybe like molten salt. This way you can heat some things and then move them around to produce vapor while also heating other parts of the liquid.

OK, but is solar energy also renewable? It’s fine if you say it’s a renewable source of energy, but technically it’s not. Solar energy comes from the sun (it’s probably obvious). But the sun produces energy mainly due to nuclear fusion reactions in the nucleus. Guess what? In 5 billion years, the sun will run out of energy. So it’s not technically renewable, but over the lifetime of the sun, it’s virtually unlimited.

Hydroelectric power

I would like to call it “hydroelectricity” instead of hydroelectric, but it is the common name that everyone uses. The point is, we’ve been using a form of hydroelectricity for a long time – the water wheel is much older than the invention of electricity. In terms of electrical energy, it is not too complicated. In fact, it’s mostly like the electric power of fossil fuels. However, instead of using steam to spin an electric turbine, you are using falling water or, technically, moving water resulting from a change in height.