Generation & Distribution
Electricity is typically generated via turbines driven from fluid flow: water, steam, or gas. Commonly, coal or petroleum is combusted to boil water. Pressurized steam spins turbine blades, which generate electricity through electromagnetic induction: producing a potential difference – voltage – across a conductor exposed to a varying magnetic field.
Wind or waterfall can also power turbines, as can pressurized gas from combusting natural gas or other light fossil fuel. Huge mirrors may be used to focus the sun’s heat, thereby generating steam. Via controlled massive radioactive decay, nuclear fission can also generate steam, as well as create waste that is incredibly difficult and expensive to dispose of.
Any engine that can power a rotating wheel can be used to generate electricity. Reciprocating (piston) engines, such as those used in automobiles, may be employed for power generation.
Electricity can also be generated more immediately: by converting the sun’s heat energy into direct current. Solar panels perform this trick.
While sunshine is free, photovoltaic cells are relatively expensive, owing largely to their conversion inefficiency. But photovoltaic technology continues to advance and will increasingly be deployed in the sunnier parts of the globe, especially in developing countries which lack inexpensive access to fossil fuels.
Commercially, the fuel used to generate electricity is determined by load generation characteristics. Base load is the level of power always needed. As electric utilities always face a large base load, the cheapest fuel is preferred to meet that load. Historically, this has been coal; then came a day favoring beta decay.