Oddly, electricity is one of those things we never think about. It’s odd because electricity and electric motors have proven to be the most efficient means of producing mechanical work in history or mankind. It’s on all the time, easy to transport, always ready and waiting for you to use it. The utility company makes plenty and is very happy to bill you for all you can use.
Generating electricity in one sense is one of the simplest mechatronic arrangements ever. Heat water till you get steam, drive a turbine with the steam, drive a “motor” with the turbine. Voila’! You have electricity. The complicated part is scaling this up to the gigawatts needed to run things and distributing the power over millions of square miles to the 300 million Americans and tens of thousands of businesses who need power.
Natural gas-fired plants, coal-fired plants, even municipal waste-fired power plants use anything that will burn to create steam. Note that the only time electricity is generated from gasoline is in stand by generators. That said, lots of creative strategies have been employed to provide massive fuel sources to generate the necessary steam. Coal is still the cheapest, in spite of the logistics problem of getting coal from the ground and shipping entire train loads to the point of use. Burning shredded car tires has been demonstrated as a way to get rid of tires and fuel to the generation of steam. A lot of research has been focused on cleaning up power plants over the last few decades, and while it’s not perfect, the kilowatt-hour is the best energy deal anywhere.
Nuclear power plants use radioactive fuel to produce the heat to generate steam. The only difference is that this is not a combustion process. The only other non-combustion process for generating electricity is from the flow of water. Damming up water to form a lake creates an opportunity to take advantage of the high-pressure drop available to turn generators directly from the flow of water.
Steam turbines and jet engine turbines are very similar and there are several classes of turbine generators used for making electricity. The microturbine generator has matured as a stable technology and is small enough and efficient enough to be used as portable power. Recently, WalMart demonstrated an experimental freight truck using a Capstone turbine and hybrid electric drive train with outstanding results.
All variations on the same basic theme, turn a generator and make electricity.