How Electricity Is Generated

Most people know a thing or two about how the everyday things work. They know (more or less) how food gets to their table. They know how water is supplied to them and where it comes from. But how many people know how electricity is supplied to their home 24/7, day in and out? Probably not.

Let me take a quick step back. Sure, most know that electricity is generated, but HOW is it generated? This is the mystery. Well, fortunately, it’s not all that hard to understand. So let’s briefly and simply see how it’s done.

hydro-energyFirst, you’ll need to know that electricity is generated is a few different ways. You have nuclear power, solar power, hydroelectric power, power from fossil fuels, etc. So let’s group them into similar categories.

Nuclear power, fossil fuel power and any type of power generated where something is burned are really steam powered. That’s right, just like in the trains of days long past. You see, the only reason anything is burned (or in the cast of nuclear, brought to a sustained reaction) is to generate heat. This heat, while being energy, needs to be converted into electricity. This is done by using the heat to boil water. The water evaporates and the steam builds up. It is then used to turn a turbine which uses the mechanical energy and converts it to electrical energy. So the trail of energy conversion goes like this:

chemical energy > mechanical energy > electrical energy

See? Not all that complicated.

Now, power obtained from hydroelectric or wind power works by getting a turbine to move directly. In hydropower, you usually have a dam that forces water to rise to a certain depth. This creates a good deal of water pressure. That water pressure is used to directly turn a turbine and thus create electricity. With wind energy, the naturally occurring wind turns the blades of the windmills, which is hooked directly to the turbine. So they are actually quite similar to the earlier ones, just with a missing step in the conversion of energy:

mechanical energy > electrical energy

Now, just to round this out, the turbines create electricity using a principle of electromagnetism. You may have done this experiment in school. If you take a large nail and wrap a copper wire around it many times in a tight spiral and then run an electric current through the wire, you will have turned the nail into a magnet. Specifically, an electromagnet. Well, the reverse is true as well. If you use magnets, you can create electricity. When you pass a magnet next to another, a charge of electricity is created. So a turbine is a circular series of permanent or electromagnets that spin in close proximity to other magnets. This creates an electrical charge and that’s how the electricity is created.

solar-powerNow, the only one that doesn’t work this way is solar power. Solar cells (or photovoltaic cells) work by directly converting sunlight into electricity. There is no change to chemical or mechanical energy at all. Sunlight hits the solar cells and electricity is immediately output. Now, you would think that this makes for a more efficient system, but unfortunately, that isn’t true. Solar cells only convert less than 20% of the energy hitting them into electricity. So to generate a good deal of power, many, many, many square feet of cells are required (this is why many people who generate their own solar power are always looking for ideas on how to reduce energy bill costs as they need to cut their use).

Actually, there is another type of solar energy that works similarly to the first ones mentioned. Some solar plants use large arrays of mirrors to direct sunlight to a water tower. The water boils and the resulting steam, you guessed it, is used to turn a turbine. So again we have a system wherein we go from chemical energy (boiling the water) to mechanical energy over into electrical energy.

Electric Meter
Close-up of electric meter face showing kilowatt hours.

So now you know a thing or two about the process of electricity generation. Now, you may have noticed that some of these methods are more sustainable than others. We are never going to run out of sunlight or wind, and we still have plenty of rivers with which to create dams. So these sources of energy, outside of being clean in that they don’t produce pollution, are also virtually unlimited. We definitely need to focus more of our efforts on building more of these types of power plants in the near future. They are environmentally sound and will keep us energized well into the future.