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Fission is a bad complement for solar power. A good complement for solar provides dispatchable fill-in-the-gaps type of power. However, nuclear power plants

Fission is a bad complement for solar power. A good complement for solar provides dispatchable fill-in-the-gaps type of power. However, nuclear power plants cost about the same amount of money per hour whether they're running or not, so are poorly suited as a solar complement. You can get to 100% carbon free by using a combination of overprovisioning, source diversity, geographic diversity, storage and statistics. You can't get to 100% but you can get to an arbitrary number of nines and say "good enough". The grid is only 99.99% reliable so having generation be better than that has little value. If you really want 100% reliability out of a primarily-solar grid you choose something the opposite of nuclear: something cheap to build but expensive to fuel. For example, synthetic natural gas. The cost of the fuel has little relevance when it only has a duty cycle of 0.1%. And they're cheap to build and likely don't even need building because we already have lots of them. China built a lot of nuclear reactors in the 2010's, but is slowing their build rate. 10GW/year of nuclear power is not very impressive in a country that built 100GW of solar in the first half of 2024. That being said, I still support restarting TMI. The main costs of nuclear are in building and decomissioning them. We've already incurred the cost of building TMI and we're already on the hook for decomissioning it, so running it is likely cost-effective once you remove the sunk costs.

NoMoreNicksLeft 2y ago
> However, nuclear power plants cost about the same amount of money per hour whether they're running or not, so are poorly suited as a solar complement. I think this is why they call it baseload. Yes it costs the same, used or unused... but it's always there, ready to be used. This is its strength, not a defect. > If you really want 100% reliability out of a primarily-solar grid But no reasonable person wants that. They want "100% reliability, and who cares where it comes from". If you're environmentally minded, you can tack on a "with no carbon"... but even that isn't the same thing as a "primarily solar grid".
- bryanlarsen 2y ago
  baseload is base load, not base generation. Base generation is not a thing. Way back when, they realized that grids had a base load below which it never dropped. They realized that if they designed some of their plants without the expensive features which allowed them to be turned on and off quickly, they could build plants cheaper. You don't design grids for base load, you design grids for peak load in all scenarios. If you can handle peak, you can also handle base. Baseload is for cost optimization. And nuclear is a horrible way to optimize cost.
credit_guy 2y ago
What you say makes sense. But what if we need to generate 50 times more electricity than we do now? At some point solar and wind energy will start being very expensive because we'll run out of cheap land. You might think 50 is absurd, but consider this: right now only about 30% of our energy consumption (and therefore emissions) is electricity. If we want to cut emissions to zero, we need to transition most of our energy use to electricity. The big culprits are transportation, steel, concrete and fertilizers. That's a factor of 3. Then we want to increase everyone's standards of living to match the current standard of living of the average American or European person. That's another factor of 3. Then we want to increase our (clean) energy use. Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions in the atmosphere. If, as Elon wants, we end up having hundreds or thousands of launches per day, and we want these launches to be net zero, then we need to find a way to manufacture hundreds of millions of tons of synthetic fuel each year. AI will also consume a lot of electricity. We will also need to build cities, if we are to lift billions of people out of their current rural life (in Africa, South America, India, etc). Everybody talks about solar as if the goal is to replace the current generation capacity. But the goal is to do that, and then more, much, much more. I think you need nuclear for that.
- bryanlarsen 2y ago
  > At some point solar and wind energy will start being very expensive because we'll run out of cheap land. Yes that might happen. But it'll happen at a number much greater than 50X. And it's a problem that'll only happen if we solve the global warming problem first. > right now only about 30% of our energy consumption (and therefore emissions) is electricity. If we want to cut emissions to zero, we need to transition most of our energy use to electricity. The big culprits are transportation, steel, concrete and fertilizers. That's a factor of 3. But we mostly use fuels that are 30% - 60% efficient plus wastage for production, refining and transporting. Over 2/3rds of the energy we use gets wasted as heat. So we've got a factor of 1/3 to cancel out your 3 here. It's not completely efficient so it's actually about 1.2X, not 3X. > Then we want to increase everyone's standards of living to match the current standard of living of the average American or European person. Yep, that's a good 3X, if not more there. But unfortunately it's going to take decades to accomplish this. > Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions in the atmosphere. If, as Elon wants, we end up having hundreds or thousands of launches per day, and we want these launches to be net zero, then we need to find a way to manufacture hundreds of millions of tons of synthetic fuel each year. > Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions Each launch would then be a 0.00001X, and is approximately equivalent to a trans-pacific plane flight. Thousands of flights per year would not be a significant fraction of the Earth's emissions. Hundreds of thousands of flights would be. - solar is fine up to around 500X - which won't happen this century - when it happens power will be abundant enough that the cost calculations will be radically different - technology will also be radically different. Maybe we'll use anti-matter reactors or something.

NoMoreNicksLeft 2y ago

> However, nuclear power plants cost about the same amount of money per hour whether they're running or not, so are poorly suited as a solar complement. I think this is why they call it baseload. Yes it costs the same, used or unused... but it's always there, ready to be used. This is its strength, not a defect. > If you really want 100% reliability out of a primarily-solar grid But no reasonable person wants that. They want "100% reliability, and who cares where it comes from". If you're environmentally minded, you can tack on a "with no carbon"... but even that isn't the same thing as a "primarily solar grid".

bryanlarsen 2y ago
baseload is base load, not base generation. Base generation is not a thing. Way back when, they realized that grids had a base load below which it never dropped. They realized that if they designed some of their plants without the expensive features which allowed them to be turned on and off quickly, they could build plants cheaper. You don't design grids for base load, you design grids for peak load in all scenarios. If you can handle peak, you can also handle base. Baseload is for cost optimization. And nuclear is a horrible way to optimize cost.

credit_guy 2y ago

What you say makes sense. But what if we need to generate 50 times more electricity than we do now? At some point solar and wind energy will start being very expensive because we'll run out of cheap land. You might think 50 is absurd, but consider this: right now only about 30% of our energy consumption (and therefore emissions) is electricity. If we want to cut emissions to zero, we need to transition most of our energy use to electricity. The big culprits are transportation, steel, concrete and fertilizers. That's a factor of 3. Then we want to increase everyone's standards of living to match the current standard of living of the average American or European person. That's another factor of 3. Then we want to increase our (clean) energy use. Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions in the atmosphere. If, as Elon wants, we end up having hundreds or thousands of launches per day, and we want these launches to be net zero, then we need to find a way to manufacture hundreds of millions of tons of synthetic fuel each year. AI will also consume a lot of electricity. We will also need to build cities, if we are to lift billions of people out of their current rural life (in Africa, South America, India, etc). Everybody talks about solar as if the goal is to replace the current generation capacity. But the goal is to do that, and then more, much, much more. I think you need nuclear for that.

bryanlarsen 2y ago
> At some point solar and wind energy will start being very expensive because we'll run out of cheap land. Yes that might happen. But it'll happen at a number much greater than 50X. And it's a problem that'll only happen if we solve the global warming problem first. > right now only about 30% of our energy consumption (and therefore emissions) is electricity. If we want to cut emissions to zero, we need to transition most of our energy use to electricity. The big culprits are transportation, steel, concrete and fertilizers. That's a factor of 3. But we mostly use fuels that are 30% - 60% efficient plus wastage for production, refining and transporting. Over 2/3rds of the energy we use gets wasted as heat. So we've got a factor of 1/3 to cancel out your 3 here. It's not completely efficient so it's actually about 1.2X, not 3X. > Then we want to increase everyone's standards of living to match the current standard of living of the average American or European person. Yep, that's a good 3X, if not more there. But unfortunately it's going to take decades to accomplish this. > Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions in the atmosphere. If, as Elon wants, we end up having hundreds or thousands of launches per day, and we want these launches to be net zero, then we need to find a way to manufacture hundreds of millions of tons of synthetic fuel each year. > Each SpaceX Starship launch puts about 5000 tons of CO2-equivalent emissions Each launch would then be a 0.00001X, and is approximately equivalent to a trans-pacific plane flight. Thousands of flights per year would not be a significant fraction of the Earth's emissions. Hundreds of thousands of flights would be. - solar is fine up to around 500X - which won't happen this century - when it happens power will be abundant enough that the cost calculations will be radically different - technology will also be radically different. Maybe we'll use anti-matter reactors or something.