Nuclear power appears to be a powerful way to make steam that spins a turbine. Same with geothermal, wind, & hydro. Maybe not solar? Isn’t energy lost in the multiple energy conversions (heat, water state, kinetic)? Is it theoretically possible to have a power source that more directly moves electrons through a circuit? If solar is the only one that can, it’s limited in efficiency and where it can be used. What about power generation undersea or on Ganymede or something?
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Plenty of other methods. I think it’s worth pointing that a turbine doesn’t generate electricity by itself. You can use a turbine to do any number of things. Such as turn a propellor on a ship.
To produce electricity you need to connect the output shaft of the turbine to a *Generator*.
You can also spin a generator from some other source of rotary motion such as a diesel engine. It’s common to use large diesels as a source of backup power during grid failures, for example. However since diesel is somewhat expensive and diesel engines have a lot of moving parts they’re not typically used for main grid power.
One commonly mentioned method in the news is Fuel Cells. These use hydrogen or other materials like ammonia or zinc, and oxygen in the air to generate an electrical current. They are a subset of batteries, however they are not rechargeable and require a continuous supply of reactants. The other downside is that hydrogen and ammonia aren’t widely available raw materials on earth, so such fuels must be produced synthetically. This always requires more energy input than you will get back out from the fuel cell later. So it’s generally cheaper to just send that electrical power over wires rather than adding extra steps.
Another method similarly to solar cells (technically Photovoltaic Cells) is Thermoelectric cells AKA Seebeck Cells. Typically these use semiconductor materials similar to PV cells. However instead of light being used to create a voltage, they use heat flow from a hot surface to a cold one.
However these are very inefficient so they’re not cost-effective for large-scale generation. They’re useful when you have a source of waste heat and want to gain a small amount of electricity to power some small electronic device. They’re also useful because they have no moving parts and have proved incredibly reliable. They’re sometimes used on spacecraft.
Another method is a linear alternator. These are pretty simple. They’re a cylindrical magnet inside a tube, surrounded by several coils of wire. The magnet can be made to reciprocate in some way. As the magnet passes a given set of coils the changing field induces a current in those coils. This can be converted into standard AC or DC using electronic switching devices.
These could potentially be attached directly to a piston or set of pistons mounted on a heavy spring, doing away with the crankshaft and connecting rods, thus increasing reliability of a piston-driven generator.
Another method is called thermionic conversion. This takes advantage of the tendency of electrons to “boil off” the surface of a material at high temperatures, in a vacuum. This is called *Thermionic Emission*. If a relatively cold metal plate is placed around the hot object the emitted electrons will collect on the plate. This produces a difference in voltage between the hot object and cold collector plate. This can be used to produce a significant current. Since this method requires a vacuum it’s mostly been used in space. Typically, the heat source is a radioactive isotope like strontium-90 or plutonium-238 with a relatively short half life.
You could also potentially heat a strip of tungsten metal with a special coating, using a large lens or mirror to concentrate sunlight on it, to produce electrons in the same way. So in space this method may be more efficient and reliable than solar cells.
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