It’s been more than 200 years since the widespread implementation of the steam engine.
Why is this still the most prevalent means of producing electricity? With things like fusion reactors, why is it so hard to convert the thermal energy into electrical energy?
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There’s a method of directly generating energy from heat (Seebeck effect), but it’s extremely inefficient. About 5% efficiency compared to the steam method which can be around 40% efficiency.
In general, it’s just not useful. However some technologies in space utilizes thermoelectric generators for simple electronics. In that case, most space probes are energy efficient enough that a steady small energy generation can be useful.
It’s simple, efficient, and cheap.
Make water hot -> steam runs a turbine -> electricity -> steam turns back into water.
It works at all times, in all weather. The water used can be reused.
It is the simplest most effective way. Electricity is produced by rotating magnets. Steam creates pressure. Pressure rotate magents.
Because it’s actually difficult to find a way of turning heat into mechanical movement. One simple way though is to take that heat and add it to a sealed container full of water. When the water boils steam comes out of the water, and the pressure in the container goes up. As you let the pressure out you can run the steam through a turbine, and get mechanical movement that way. The turbine turns, electricity is generated, and boom, you have a power plant.
Scale. The largest diesel engine in the world makes about 1200000 hp and is used turn a large propeller at a pretty constant speed about 120 rpm (direct drive). A steam plant needs to make large amounts of power but be able to handle a load change from the grid as well. So steam turn big turbines that spin at high speed low torque , about 10000 + rpm that goes through a reduction gear to go low speed high torque about 120 rpm. That high torque allows for load changes from the grid to not slow down the generator and keep the electrical production at a constant 60 hz which is need to stable power.
Nuclear plants still use steam they just generate heat a different way
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