Every Plug Ends at a Spinning Magnet - power stations, fission and the solar exception

That board’s loop pays electricity to push heat uphill. A steam power station runs the same loop forwards: it lets heat fall downhill and catches some of the fall as electricity.

Before you start. You need three earlier lessons, each in one line. The Socket Is a Waterfall - volts, amps, watts and the bill: power is volts times amps, and the bill counts kilowatt-hours. Spin From a Wire - motors, generators, speakers and the induction hob: spin a coil past a magnet and current flows; that is a generator. Cold Is a Lie - fridge, AC, heat pump: heat flows downhill from hot to cold for free, and no machine can use all of it. This lesson follows the wire from your socket back to where it starts.

The idea in 30 seconds

Almost all grid electricity comes from a generator, a coil spun past a magnet; power stations differ only in what turns the shaft.
Coal, gas and nuclear stations boil water; the steam spins a turbine, the turbine spins the generator.
A steam station is the fridge’s loop run forwards, a heat engine, so the second law caps it; real US coal and nuclear fleets turned about a third of their heat into electricity in 2024.
Fission splits uranium nuclei, releasing about three million times the energy of the same mass of coal, but only to boil water.
Capacity factor is the share of a year’s possible output a station actually delivers: about 91% for US nuclear and 23% for solar in 2024.
A solar cell is the exception: light frees electrons directly, with no magnet, no turbine and no heat engine.

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