Electrical generation: all generator/turbine-based from here on out?

Factual Questions
1

I was on a plane today, and noticed a rather large coal plant out the window at one point. It occurred to me that every method of generating electricity on a commercial/industrial scale that I know about basically boils down to the one method: getting some kind of turbine to turn, then using the metal wire and magnets and whatnot and poof, electricity. Whether the power for the turbine is water heated by nuclear or coal; or wind or rivers, it all seems pretty much the same… the only exception I can think of is solar, which is still not widely used.

So is my perception correct, that pretty much all electricity generation boils down to turbines and generators?

Are there some cutting-edge technologies that maybe, someday, could replace those mechanics? (I’m not talking about using different fuel, but actually a different way to get electrons jiggling and moving as we want them to.)

2

Magnetohydrodynamic generators have been proposed for ages, but no one has ever been able to get them working better than the old tried-and-true turbines.

3

Wind power and some types of solar power don’t involve “heat engines”, which IIRC is the name for the basic class of machine that the turbine generators you are talking about fall into. Machines that convert heat into usable energy.

Nuclear batteries are another example; they convert decay particles into energy. Sort of a variation on a solar panel, actually.

Fuel cells also aren’t turbines.

4

I think the OP is misusing the term “turbine” to mean “some sort of spinning generator”.

For large scale electrical power generation (residential and industrial service), coal and nukes are the big guys. They do most of the work. Natural gas and hydroelectric do some, but they aren’t as big. All of the “green” energies like solar and wind are just a tiny drop in the bucket. So, yeah, almost all of the power generation comes from spinning generators of some sort, and most of it is from steam turbines.

Right now, if you need a big honking bunch of power, in most places you realistically have a choice between coal or nukes, so unfortunately it’s a choice of do you want to ruin the planet with greenhouse gases or do you want to make some god-awful stuff that will poison some part of the earth for such a long time that it’s difficult to even wrap your mind around it. Everyone is talking about green energy, but in the near future, there’s no hope at all for anything “green” to make a realistic dent in the world’s power needs. Wind farms take up huge amounts of real estate and don’t provide all that much power compared to a large nuke or coal plant. Damming up a river for hydroelectric has huge ecological repercussions, and many rivers are being used almost to capacity as it is and can’t afford to have someone slow down the flow at all. Geothermal and other sources are just too limited to be a major provider. They are good for some small applications (Iceland, for example), but you aren’t going to power the world’s power grids from them.

The one thing that (IMHO) really does have hope for the future is solar. Back when I first started engineering school, solar power was so ungodly expensive that no one could afford it, not even the rich. Now, if you’re a movie star or some other person who is definitely a few tax brackets over my head, you can actually afford to power your home with solar. In the long run you’ll end up paying significantly more than what the power company would charge you, but if you are wealthy, you can do it. It’s a bit too much of a burden for us poor folks right now though.

However, solar is getting cheaper, and fossil fuels and nukes aren’t. As long as this continues, it won’t be too much longer before solar can realistically compete with the power companies. Then things could get interesting. Right now, our electrical supply is based on big honking plants with great big wires getting it to where it needs to go. With solar, though, the generation would be right at your house. You could power your home and maybe even plug in your electric car at night and would no longer need to be connected to the grid like you are now. Big power plants could eventually become a thing of the past, or at least would see only limited use in areas where the sunlight sucks.

Personally, I don’t think that this sort of thing is really that far away into the future. Some areas already have state or local incentives that make solar competitive with the power company. As the price of solar continues to drop, it won’t be long before these incentives will no longer be necessary.

5

Diesel engines. They are heat engines, but certainly not turbines. They can actually run more efficiently than a steam turbine, but can’t be built in anything like the power. They need to suck more expensive fuel too, so their utility is limited to niche power generation needs.

The other aspect to turbines is when they burn the fuel directly - a gas turbine. Gas turbines that are fed natural gas are a very useful from of power generation as they can come on stream almost instantly, and are thus great for peak demand. Things that heat water for steam take some time to get to a working level, and don’t take too well to changes in operating conditions. So a mix is always good. Stationary or marine gas turbines are pretty close their aeronautical cousins in design, and are basically jet engines optimised for shaft power and slightly different pressures.

One of my favorite exhibits in the London Science Museum is the first ever multi-stage steam turbine built by Charles Parsons. It is tiny. It looks like a lovely scale model - a few feet long. But it worked, and delivered real power. It revolutionised the turbine and made the idea workable. That little model looks pretty much identical to modern machines.

6

I think the 2 posts above mine are missing the OP just a little bit.
Another method of obtaining electricity from heat is the thermoelectric effect, although I’m not sure if it could be scaled to any practicable level.

7

Fuel cells (as mentioned by Der Trihs) meet all the OP’s criteria. They are an existing and cutting-edge technology that convert the chemical energy in fuel directly into electrical energy at high efficiency without any rotating machines.

8

If only somebody would invent the piezoelectric generator run by a wind mill thumping up and down on the piezoelectric material.

Yes piezoelectric exists but is not generally suitable for most consumers to use. The same goes for thermo electric generation by heating two appropriate metals.

9

I’ve often said that I would have no objection to living next door to an industrial-scale wind farm, but I don’t fancy the idea so much if it’s one of your proposed thumpy-piezo models.

I saw an article recently on a wind generator that used a taut vibrating ribbon to harness wind power - I think that used magnets and coils, rather than piezo, but I expect it could be done.

10

Wind energy is harvested with a wind turbine. Thus, it’s another example of the OP’s turbines. It isn’t correct to jump to the statement that the OP’s turbines are heat engines and then exclude wind energy.

The thermoelectric effect is neat in some ways. For example it allows using radioisotopic decay on spacecraft traveling too far from the sun for solar power to work well. But it is quite inefficient and can’t compete with other heat engines for most purposes.

11

I’m still reading through some of the responses and cites, but it sounds like there are really no impending breakthroughs on how to turn our various fuels (coal, nuclear, natural gas, etc) into electricity… although there are a couple of theoretical possibilities. Am I in the ballpark?

Also, do I understand correctly that fuel cells aren’t really being looked at as large scale electrical generators, but rather something that may be used in place of batteries?

(ETA: I still have to do some reading on this thermoelectric effect. I’m not understanding it at all.)

12

About fuel cells - one of the great things about having fuel cells on cars is supposed to be that you can plug them into the house and power the house and the grid with them, or at least so I read someplace. This sounds a bit weird, because generally you have to make some kinds of compromises on a power source to make it mobile, so it would be a surprise if vehicles displacing power generated at the station made sense within the same grid.

About the thermoelectric effect, try this for understanding. Heat energy in a solid is energy in the form of various small, rapid vibrations of the atoms and molecules. If there is a temperature gradient, then there are more vibrations in the hot areas and fewer in the cold areas, and a preponderance of vibrations traveling as waves from the hot areas to the cold areas. In any conductive material, there is some tendency of the electrons to get swept along with such waves, like driftwood on ocean waves. However, the strength of this effect depends on the material. Bisnuth and antimony, for example, have very different strengths for this effect. Therefore if you join one end of a pair of wires, one antimony and one bismuth, and put a thermal gradient over the length of the pair, there will be a voltage difference on the unjoined end between the wires. This is called a thermocouple, and this effect is called the Seebeck effect.

Now, if you connect some small resistance between the unjoined ends, a current will flow, and the voltage will become smaller. The wires are functioning as a heat engine, doing work to the resistance by passing a current through it. This is called the Thomson effect (I think).

If there was no thermal gradient, but you connected a DC power source such as a battery instead of a resistive load, the wires would develop a thermal gradient, and the far end would become hot or cold. Switching the polarity of the battery would change whether the far end was hot or cold. This is called the Peltier effect. Actually, you might not quite be able to make the far end cold; whether this works or not depends on a kind of efficiency or performance metric for that pair of materials, and they go to some trouble to make it good when they actually want to use this for practical purposes. But when they do, it works quite well. The small refrigerators without moving parts that are made for automobile use work this way, as well as some CPU coolers for computers.

13

No, that’s not correct. Stationary power generation applications are being developed, by companies like Siemens Westinghouse.

14

What I recall reading was that they could charge when power demand was lowest (overnight), and provide a little power during peak demand. Overall they’d be loads, but helping to hit peak demand could plausibly be a benefit even if they’re not as efficient as a real power plant.

15

[tangent]
Naval nuclear power plants are designed to handle changes in operating conditions quite nicely (Not sure about land-based nuclear power plants)

Granted, from cold iron to full power takes a few hours, but once under way, the plant has to be able to handle fairly quick power changes.
Consider what happens when the ship is in wartime maneuvers: the bridge might request flank speed, drop down to ahead 2/3, go back up to flank, then go to back-emergency (dumping full power into a set of highly inefficient reversing turbines) then go to all-stop.

All through this process, the reactor automatically adjusts power output to match steam demand in fairly quick fashion. Indeed, the reactor operator is not tweaking rods to handle this; the reactor does it all by itself.

Certainly nothing as snappy as a gas turbine, but far from sluggish response time.

(of course, the GT will always win in a race to start up from cold iron, which was your initial point).
[/tangent]