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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Yes and no, electricity is generated by a lot of stuff, but the only way that is really useful is moving a magnet over coiled copper.
The easiest way to do that consistently on an industrial scale is by rotating a magnet really fast in a coiled piece of copper.
It turns out, water is also basically the best way to continuously turn something is water, either by having waterwheels in the River or windmills in the wind to harness that power into mills to grind our grain into meal even before we discovered electricity.
But, you are right that industrial energy production isn’t very high efficiency, Coal is about 30-45% efficiency, and similar values for nuclear power in capturing the heat that is radiated. You are also right that photovoltaic is the most efficient at turning energy into electricity with some newer designs hitting as high as 50%, but that’s only one part of the problem, since photovoltaic relies on surface area exposed to the sun the space cost is prohibitive in some areas while negligible in others, and they obviously have the problem of generating most of its power at the time we need the least power and finding ways to store that excess energy so that there is plenty to use at night and early in the morning is one of the open questions in civil engineering. One of the best ways we have to do that is use a pump to store water really high up and then when you need more power to let it fall down and spin a turbine, but the places where Solar is most viable tend to be deserts.
So, while other forms of electricity generation get less electricity per calorie burned than Solar, other forms are more compact and better able to match output to demand curves of when we need them, both of which are actively being worked on.
https://en.wikipedia.org/wiki/Wave_power?wprov=sfla1
You can also generate electricity with floating rigs that move with the waves.
There is a Solar energy plant at the NV/CA border that reflects sun rays on a focal point to create steam which turns a turbine. Three of these towering solar steam generators, in fact.
DC generators do exist, they’re called a **Dynamo,** which functions in the same manor as an AC generator, they just use a commutator (which periodically flips the current direction) and some other components to convert the spinning motion to direct current. They also have brushes which need to be replaced and they (dynamo) tend to be very inefficient and are being phased out. Tidal generators are something that is being explored, but those also generate AC power.
AC is easier to generate and easier to transmit over long distances and is the main reason that AC is used predominately
>Is it theoretically possible to have a power source that more directly moves electrons through a circuit?
Theoretically, yes it is, however your need a rotating magnetic field to generate electron flow from mechanical movement, and this creates AC power by default. To create DC power you need to rectify that AC power which reduces the efficiency and needs more parts in the dynamo.
>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?
Countries like Russia and the US have explored the idea of placing small nuclear reactors on the sea floor to use the ocean as a natural heatsink to keep the reactors cool. These have military implications so they aren’t discussed too often. Like I said above Tidal Generators are also something being worked on, but again these produce AC current. The best way to generate DC power would be to place solar panel arrays in space (outside of the atmosphere to capture the full energy of the photons) and send the power down to earth
In principle AC power is incredibly easy to generate compared to DC, and AC is much easier to transmit long distances because of it’s ability to easily step-up and step-down the voltage through the use of transformers.
In a word – yes, you’re right. It’s actually amazing how many modern technologies come back to “making a thing spin”. Power generation? Working out a way to make a turbine spin. Fridge? Making an engine spin. Washing machine? Spin. Car? Spin. Airplane? Spin. Heating? Spin. Cooling? Believe it or not, also spin.
photoelectric effect, piezoelectric effect, electrical induction….and i dont know what you call how thermocouples produce electricity… induction is just the most practical for large scale production
There are even solar plants that use turbines. Earlier large scale solar used mirrors reflecting sunlight on to a boiler to create steam and power a turbine rather than needing large amounts of highly inefficient and expensive photovoltaic panels.
I’ve seen alot of good answers already explaining how we harvest energy in general, so I am only gonna touch up quickly on your titular question.
Electricity is porduced my moving electrones, so there has to be work that gets completed somewhere.
Its easiest to harvest directed forces such as mechanical forces. Heat isnt directed, so its really hard to harvest. So for us its easier to convert it first into a directed force.
In the case of photovoltaic (not to be confused with solar panels, which work by absorbing the suns heat into tiny tubes of water that run across the panel) we use chemical forces to generate power. Photovoltaic isnt the only place we do that though, for example alkine batteries also harvest chemical energies in order to produce electricity. Generally you’d think of a battery as something you need to charge up first. But in the case of alkine its metals that got mined from the ground, that dont get charged up or anything, that produce the electricity. Or potato batteries work the same way. Even batteries that you do have to charge up first, use chemical forces, to release the stored energy again (usually, cause you could also think of a dam as a giant battery for potential energy, but thats not what I mean here).
Current can be generated by moving wire near a magnetic field; or, moving the magnetic field near a loop or wire. Rotating motion is not the only way to do this but is a great way to do this. Imagine a device where you move a loop of wire in a straight line through a magnetic field – no matter how long it is, ultimately you have to move your wire back where it started!
There are other ways to generate electrical flow more directly. Other than PV, they tend to have drawbacks or be less efficient. The Seebeck effect generates voltage from a heat difference – the energy you can get is less than 10% of the heat energy flowing through the part. PV is now >20% but won’t ever hit 50% for example.
Aside from the obvious like photovoltaic solar there are traditional fossil fuel plants that function via direct energy conversion from magnetic plasma streams.
The basic principle is that moving plasma can be used to create a magnetic field in the same way that other moving conductors can.
https://en.wikipedia.org/wiki/Magnetohydrodynamic_generator
However they have limited mass commercial appeal aside from being used where plasma is already generated and needs to be cooled, because none of the current designs are more efficient than steam turbine designs, and the maintenance requirements are high which removes the primary benefit of having no moving parts.
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