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As of 2021, global electrical production was about 7 TW. And the largest single power plant is the Three Gorges Dam at a capacity of 22.5 GW. My hero needs a single power plant with 50 times more capacity. What types of generation are possible?

  • Is there a large enough river for hydropower? It would need to be 50x the scale of the Three Gorges Dam, or 15x the size of the largest proposed Grand Inga Dam.
  • The largest coal plant is 3.5 GW. Could it be scaled up 300x?
  • Nuclear options? Uranium fission or D-T fusion? The latter would require a solution for tritium supply.
  • Solar and wind are out because the required area would be too large.
  • Some kind of geothermal megaproject?
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    $\begingroup$ Hello Doug, welcome to Worldbuilding. You don't mention the technological basis for your question. If we assume it's the Real World today, then nuclear is your only option. But that might be unimaginative. Could you choose either the science-based tag or the science-fiction tag so we know how far we can take answers? Honestly, I'd vote for the science-fiction tag. That would allow for answers like an array of solar panels in space.... $\endgroup$
    – JBH
    Dec 20, 2022 at 19:54
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    $\begingroup$ Thanks. I have added the science-fiction tag for technological basis. $\endgroup$
    – Doug
    Dec 20, 2022 at 20:11
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    $\begingroup$ That might sound like a joke question, but it's serious. Batteries, CPUs, cities, and organisms all work that way: once you've built something big enough that it's inefficient to build it bigger, you build a bunch of them next to each other and have them share infrastructure for resource input, waste disposal, security, and heat rejection, whether they're battery cells, processors, buildings, or cells in your body. There's no immediately obvious reason to me why one wouldn't add power plants to the list. $\endgroup$
    – g s
    Dec 20, 2022 at 20:35
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    $\begingroup$ @gs and a side benefit, one of them being taken down due to a failure or for regular maintenance only means losing 0.1% of your total output. $\endgroup$
    – Christopher James Huff
    Dec 20, 2022 at 21:05
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    $\begingroup$ Your hero does not need "a single power plant" with 1 TW capacity. He needs five minutes of an engineer's time, who will explain to him that a watt is a watt is a watt, and the watts produced by 500 plants of 2 GW each are in no way distinguishable from the watts produced by one humongous 1 TW plant. (And anyway, a typical modern nuclear reactor is about 1,000 MW electrical; you need about 1,000 of those for your 1 TW. Whether you call them one power plant, 10 power plants, or 500 power plants is a purely administrative decision.) $\endgroup$
    – AlexP
    Dec 20, 2022 at 21:16

5 Answers 5

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If you want a single plant, and don't want wind/solar (which technically are many smaller plants), these are the possible solutions in order of least practical to most practical:

Hydropower comes close: The Atlantropa dam could have generated up to 0.4TW at perfect efficiency. I doubt there is a bigger source of hydropower than the entire Mediterranean sea drained by 200m, but with some clever megaproject-engineering, it may be possible.

Geothermal is unfortunately not very energy-dense per m^2. It's technically possible - the earth's core produces 44TW of energy every year via nuclear fission - but to capture even just a single terawatt of that would require encasing the entire land area of Russia in a massive thermo-electric blanket of some sort.

I do not know enough about nuclear to comment on it with much confidence, but it seems like nuclear fission plants have relatively small (1GW) power outputs. To get more power, you would link many of these together - this is already commonly done, as in the largest nuclear plant, Uljin NPP: a power production of ~7GW, from 6 reactors. Fusion is more speculative, as no plants exist yet, but I believe that the power density is expected to be smaller than fission, which makes very high-power designs even more unlikely. But if the story requires it (does it really require it?) a large collection of reactors is entirely possible.

Space-based solar power is something that you might consider, especially if the setting is sci-fi. In the late 1970's, NASA conducted a very thorough study on this topic, with a proposed system design of 30 3GW power stations orbiting earth in GEO. By increasing the size of the station from 5x10km to 16x30km, 30 stations would give ~1TW. Further increases could result in a single station with TW capacity, at about 120km square. However there is no need for each space-based station to have its own ground station - all 30 or more satellites could point at a single ground station. See also Willk's answer for a lunar variant on SBSP. Note that the required size of the rectenna (energy collector) on earth for a Lunar SBSP will be about 10 times bigger (~100km diameter) than for GEO based SBSP (~10km diameter). It is possible to use the land under a rectenna for farming.

Coal would probably work. But it would not be very nice. Currently, the world's generation of electricity from coal is almost 1TW, and has been higher in the past. There are enough coal reserves (and most coal is not used for electricity) that doubling electrical production from coal would not significantly change the estimated end-of-supply for coal. HOWEVER, if it was all at a single plant, it would be a disgusting industrial complex - black with soot, etc. Even with strict cleanliness rules, fires and explosions would likely be common due to coal dust. But this might be beneficial to the setting.

Depending on what setting will best enhance your story's message, you could probably pick any of these.

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Hydrogen Fusion

Sure, Deuterium-Tritium fusion is really is impressive. But what if we look for something even more powerful? Something that is much more cleaner, i.e. doesn't release a b*ttload of neutrons during fusion?

Behold, I present to you, Aneutronic Fusion (Hydrogen Fusion).

In simple layman's terms, ordinary hydrogen has just 1 proton in its nucleus and 0 neutrons. This makes it the lightest element in the universe. This element is also extremely abundant. The Milky way is composed of more than 70% hydrogen, for reference.

Pound for pound, fusing hydrogen releases nearly 50% more energy than fusing Deuterium and Tritium atoms together, and 10% more energy than simply fusing only Deuterium. This proves to be an advantage.

You can find hydrogen anywhere. Stars, nebulas, gas giants, you name it. Heck yes, you can just get it free from the oceans. Just dissolve some lye or a strong base in water, pass some electricity through it.... BOOM! There you have it, simple hydrogen.

Deuterium on the other hand constitutes only 0.015% percent of the Earth's crust. This isn't a problem, as this is sufficient enough for us. But tritium.... well, it is, two words, EXTREMELY RARE.

At any given moment, there is just 15 pounds of tritium naturally occuring on Earth. This is because tritium is radioactive, with a half life of 12 years. Tritium is also extremely hard to synthesize, requiring a ton of complex fancy apparatus and bombarding Lithium with neutrons and stuff. In other words, it is a PITA to synthesize tritium.

Fusing 1 kg of hydrogen (Protium), releases nearly 640 TJ of energy, 2% of which is lost due to neutrinos, but the loss is so insignificant that it is easy to ignore it. 640 TJ of energy is basically enough to boil 2 billion liters of water. Using a conventional steam turbine, you can convert this heat energy into hundreds of terawatts of electricity, something that your hero will be very pleased with.

However, there are multiple drawbacks to this:

  • Protium/hydrogen fusion requires temperatures and pressures that are beyond what we can generate in a lab. You need hundreds of billions of atmospheres of pressure and millions of kelvins (The temperature part is easy, the pressure part is really hard) to create conditions suitable for fusing protium to generate energy, which is a reason why most fusion reactors favor D-T fusion over P-P fusion reactions. But this can easily be ignored, considering that this is your story and you can simply handwave the issues away.

  • Making a fusion reactor requires vast amounts of money, but that can be ignored, assuming that your hero is some trillionaire guy to whom money isn't a money.

Overall, hydrogen fusion reactors should be something that your hero should consider building to generate not just 1 TW but a power plant that generates hundreds of terawatts of electricity, and also, completely neutron-free.

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Multiple Smaller Linked Plants

Consolidating from a few comments on the question -- to quote @AlexP, "a watt is a watt is a watt". Get enough smaller generators to meet your power needs and network them together, and that will look like a single 1 TW source to whatever's plugging into them.

Keep in mind that basically all major power plants work this way already, including the ones you mention in your example. Hydroelectric dams have multiple turbines all working together, nuclear plants usually have several individual reactors, fossil-fuel plants have multiple burners and turbines, solar farms have hundreds of separate panels, etc. This is important both for scaling and for redundancy, since you can shut the various components off individually as needed for maintenance or to manage output.

Granted, networking the plants to provide 1TW of power to a single point that your hero can tap into is going to be an engineering feat of its own. I'm curious to see what a power cable rated for that sort of capacity looks like!

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1 terawatt? 1 measley terawatt? Sure you can have a terawatt. Let me introduce you to

Luna Ring

https://www.engineering.com/story/could-a-lunar-solar-array-power-the-entire-earth

luna ring

Dubbed the Luna Ring, the project is “a large scale concept [looking] to create a new form of energy infrastructure”. As imagined by the Shimizu Corporation, the Luna Ring would be composed of thousands of solar panels arrayed along a 400km (250 mile) stretch on the Moon’s 11,000km (6,800 mile) equator.Using microwaves and laser light, the Luna ring would beam power back to Earth in a continuous stream, creating an “almost inexhaustible amount of energy.”According to the Shimizu Corporation, if their Luna Ring project were built on the side of the moon that consistently faces the Sun the entire system could generate around 13,000 terawatts (TW) of power. For the sake of scale, global power consumption reached 16 TW in 2006, meaning the Luna Ring could provide over 800 times more energy than we currently consume.

Yeah your hero can swipe a terawatt here and there. Luna Ring will not even notice. Chump change.

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  • $\begingroup$ A good answer, but I believe you could achieve 1 TW with a lot less. Also, I believe OP ruled out solar power for being "too large". $\endgroup$
    – BMF
    Dec 21, 2022 at 0:29
  • $\begingroup$ @BMF - I am sure OP meant required area on Earth is too large. Endangered species live there. Hawks fly into the solar panels. Historically important fields. All that. The moon has plenty of space where nothing has happened. My original concept was the entirety of the moon with panels not just some solar garter belt but I could not make a good image and so this is what I found. $\endgroup$
    – Willk
    Dec 21, 2022 at 1:57
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    $\begingroup$ I think this answer could be improved by deleting the reference and doing your own estimate, as I'm not going to trust anything said about the moon by people who have apparently never looked at it. A project whose authors apparently think that the moon has a side that consistently faces the sun is sort of the opposite of citing a source. $\endgroup$
    – g s
    Dec 21, 2022 at 3:00
  • $\begingroup$ @gs yes they botched that. It should be “continuously facing earth”. NASA has a better article but not the sweet image. sservi.nasa.gov/articles/the-luna-ring-concept $\endgroup$
    – Willk
    Dec 21, 2022 at 4:15
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    $\begingroup$ @Willk For every solar power plant on planets/moons. That's why I proposed one in eart-orbit. Given enough distance to avoid being eclipsed by the planet, they can produce 24/7. $\endgroup$
    – Matthias
    Dec 23, 2022 at 6:12
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Time for some solar power satellites (SPS)

As the area required is in space, I don't think the objection for area required really applies in their case. Problem is the cost to lift materials into orbit is prohibitive - so don't do that. Plan on capturing a convenient near-earth asteroid and converting it into about 10,000 sq. kilometers of SPS - enough for 1 TW. The microwave or laser receiver you need to be based on the earth will still be considerable, but much less than the equivalent area required to collect 1TW of land-based solar power.

I have just the asteroid you need, Apophis - as described in this article about converting Apophis into a SPS

From the article, there is sufficient material to convert Apophis into about 750 GW worth of SPS. You would be advised to capture a few smaller (150 m) asteroids first to get experience converting them into 50 GW worth of SPS each before converting Apophis.

As a bonus, you also have over 100K worth of space habitation that would be immensely value for industry, research and tourism. Elon Musk will be jealous.

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