3 ms·

Most of those are from fossil fuel or nuclear shills. You can get wildly varying numbers based on what you include and exclude. Meta analyses say current/upcom

Most of those are from fossil fuel or nuclear shills. You can get wildly varying numbers based on what you include and exclude. Meta analyses say current/upcoming techs are about as good or maybe a bit better, but energy payback time is significantly lower due to reduced lifetime. Additionally the GHG impact of nuclearand wind isn't quite proportional to energy payback time because of concrete. https://ieeexplore.ieee.org/document/8118077 https://ieeexplore.ieee.org/document/8118077 https://www.sciencedirect.com/science/article/pii/S0301421513003856 https://www.sciencedirect.com/science/article/pii/S030142151... Really though the answer is both are fine and nuclear probably wins once you include a mix of wind, hydro and storage. And embodied emissions will go down as low carbon energy becomes a bigger share. The main arguments against new nuclear are political (making new oil barons but with nuclear is stupid among other problems) and opportunity cost (using a nuclear reactor to replace 1GW of fossil fuels 80% of the time uses the same resources as using renewables to replace 10GW of fossil fuels ~40% of the time -- some of which is uncorrelated -- but at much longer delay).

Retric 4y ago
I largely agree with what you said, but that 80% capacity factor is rather nuanced. Nuclear’s capacity factor varies quite a bit depending on the local grid. France’s averaged below 70% while US nuclear reactor’s where generally over 90% largely due to the local energy mix. Solar is running into similar issues as it scales, but they both can greatly benefit from energy storage. The issue is nuclear power is so expensive it makes energy storage less appealing. So, if we are talking about a potential grid with 30% nuclear 10% hydro and the rest solar and wind then nuclear could have a 90+% capacity factor and mostly be offline in the spring and fall when seasonal demand is low. Unfortunately that means Nuclear isn’t going to scale and help with global warming. On the other hand if you want a 90% nuclear 10% hydro grid then nuclear is going to have something like a 40% capacity factor without a great deal of energy storage.
- Schroedingersat 4y ago
  In the context of "turn the most gas and coal plants off per dollar ASAP", I think 80% is pretty reasonable. Especially when you include things like plants that were paid for but never opened and various safety shutdowns. Similarly 25-30% for solar and 60% for wind with them being anticorrelated enough that you can call an equal mix ~40% over all. The other benefit is solar+wind incentivises storage development in a way that nuclear does not. Cost-wise, for many applications it's optimal to overbuild by a factor of 2 or 3 just to get energy in the sides of the energy curve. This results in energy that has been paid for, and can be turned on or off in milliseconds but has no value at 11am. Many storage technologies become viable at $10-20/MWh that need further development to be viable at higher price.
  - Retric 4y ago
    That’s a reasonable point, but I think it’s still overestimating the value of adding new nuclear power plants when you already have significant nuclear capacity. It’s clear the average capacity factor falls when you add more nuclear power. In other words rather than looking at the average capacity factor as being X%, you need to consider how much the average capacity factor falls with each additional reactor and then calculate what the effective capacity factor of that reactor must have been to hit the new average. To illiterate if 10GW averages to 80% and 11GW averages to 79% then the 11th GW must have effectively been 69%, because (80 * 10 + 69) / 11 = 79.
cinntaile 4y ago
I would say the main arguments against nuclear are political; the waste storage problem and a fear for accidents. There can also be laws against building new nuclear plants or taxes that disproportionally disadvantage nuclear. The huge capital costs don't speak in favor of nuclear either, but I do wonder how the other aspects affect even considering to build new plants. I don't really follow your opportunity cost argument. Do you mean the price of 1 plant equals the price of 10GW renewables? Are you taking into account the fact that you have to replace the renewables after about 20 years while you can run a new plant for about 60 years?
- Retric 4y ago
  After selling electricity from a solar power plant you should have enough money to build it’s replacement in less than 20 years. Both Nuclear and Solar get subsidies, but grid Solar generally doesn’t need them.
  - cinntaile 4y ago
    I was wondering if that was part of the calculations or not. It's capital that needs to be accounted for if you want to compare energy sources. The existence of subsidies shouldn't really matter, the end consumer pays for them some way or another and you factor this into the total capital cost.
- Schroedingersat 4y ago
  At $0.8/gross watt and 25% capacity, solar breaks even at around 20 years at 2c/kWh. At 3c/kWh you can also cover interest and upkeep and make a net profit. Prices are falling double digit percentages every year. The story is similar for wind, although prices are no longer falling rapidly. 2-3c/kWh for nuclear takes care of your variable costs of operation. You will never pay back the building costs at 3-4c/kWh. The financial payback time for renewables is shorter than the build time for the nuclear plant, whereas the nuclear plant will need subsidy to stay on after 20 years or so. Ie. if I have $10 billion right now, I can spend it on nuclear. In 15-20 years I will have ~0.8-1GW of net capacity that will begin to produce energy at a marginal cost of 3 to 4 cents per kWh and nothing in the bank. Or I can spend it on ~4GW net of solar. In 20 years I will have my original money back, a modest profit, and a mostly worn out system that will conservatively produce ~1-2GW net at a marginal cost of around 1c/kWh for another ten years. Additionally industry trends imply that half of my money will buy me 6-8GW net of capacity in the same space if I simply replace the panels with 30-40% efficient ones (as over half of the current costs are land, permiting, and frame). The outlook is not quite so compelling for wind, or high latitudes, but it still blows nuclear out of the water. The story also looks a little better for nuclear if you're anticipating green hydrogen or ammonia costs to be prohibitively high or you decide to bulldoze the fossil fuel plants rather than using them as part of a chemical storage system. Additionally if you are anticipating energy growth nuclear looks good in the short term (but after 60 years we're basically back at square one arguing about thermal pollution rather than CO2)

Retric 4y ago

I largely agree with what you said, but that 80% capacity factor is rather nuanced. Nuclear’s capacity factor varies quite a bit depending on the local grid. France’s averaged below 70% while US nuclear reactor’s where generally over 90% largely due to the local energy mix. Solar is running into similar issues as it scales, but they both can greatly benefit from energy storage. The issue is nuclear power is so expensive it makes energy storage less appealing. So, if we are talking about a potential grid with 30% nuclear 10% hydro and the rest solar and wind then nuclear could have a 90+% capacity factor and mostly be offline in the spring and fall when seasonal demand is low. Unfortunately that means Nuclear isn’t going to scale and help with global warming. On the other hand if you want a 90% nuclear 10% hydro grid then nuclear is going to have something like a 40% capacity factor without a great deal of energy storage.

Schroedingersat 4y ago
In the context of "turn the most gas and coal plants off per dollar ASAP", I think 80% is pretty reasonable. Especially when you include things like plants that were paid for but never opened and various safety shutdowns. Similarly 25-30% for solar and 60% for wind with them being anticorrelated enough that you can call an equal mix ~40% over all. The other benefit is solar+wind incentivises storage development in a way that nuclear does not. Cost-wise, for many applications it's optimal to overbuild by a factor of 2 or 3 just to get energy in the sides of the energy curve. This results in energy that has been paid for, and can be turned on or off in milliseconds but has no value at 11am. Many storage technologies become viable at $10-20/MWh that need further development to be viable at higher price.
- Retric 4y ago
  That’s a reasonable point, but I think it’s still overestimating the value of adding new nuclear power plants when you already have significant nuclear capacity. It’s clear the average capacity factor falls when you add more nuclear power. In other words rather than looking at the average capacity factor as being X%, you need to consider how much the average capacity factor falls with each additional reactor and then calculate what the effective capacity factor of that reactor must have been to hit the new average. To illiterate if 10GW averages to 80% and 11GW averages to 79% then the 11th GW must have effectively been 69%, because (80 * 10 + 69) / 11 = 79.

cinntaile 4y ago

I would say the main arguments against nuclear are political; the waste storage problem and a fear for accidents. There can also be laws against building new nuclear plants or taxes that disproportionally disadvantage nuclear. The huge capital costs don't speak in favor of nuclear either, but I do wonder how the other aspects affect even considering to build new plants. I don't really follow your opportunity cost argument. Do you mean the price of 1 plant equals the price of 10GW renewables? Are you taking into account the fact that you have to replace the renewables after about 20 years while you can run a new plant for about 60 years?

Retric 4y ago
After selling electricity from a solar power plant you should have enough money to build it’s replacement in less than 20 years. Both Nuclear and Solar get subsidies, but grid Solar generally doesn’t need them.
- cinntaile 4y ago
  I was wondering if that was part of the calculations or not. It's capital that needs to be accounted for if you want to compare energy sources. The existence of subsidies shouldn't really matter, the end consumer pays for them some way or another and you factor this into the total capital cost.
Schroedingersat 4y ago
At $0.8/gross watt and 25% capacity, solar breaks even at around 20 years at 2c/kWh. At 3c/kWh you can also cover interest and upkeep and make a net profit. Prices are falling double digit percentages every year. The story is similar for wind, although prices are no longer falling rapidly. 2-3c/kWh for nuclear takes care of your variable costs of operation. You will never pay back the building costs at 3-4c/kWh. The financial payback time for renewables is shorter than the build time for the nuclear plant, whereas the nuclear plant will need subsidy to stay on after 20 years or so. Ie. if I have $10 billion right now, I can spend it on nuclear. In 15-20 years I will have ~0.8-1GW of net capacity that will begin to produce energy at a marginal cost of 3 to 4 cents per kWh and nothing in the bank. Or I can spend it on ~4GW net of solar. In 20 years I will have my original money back, a modest profit, and a mostly worn out system that will conservatively produce ~1-2GW net at a marginal cost of around 1c/kWh for another ten years. Additionally industry trends imply that half of my money will buy me 6-8GW net of capacity in the same space if I simply replace the panels with 30-40% efficient ones (as over half of the current costs are land, permiting, and frame). The outlook is not quite so compelling for wind, or high latitudes, but it still blows nuclear out of the water. The story also looks a little better for nuclear if you're anticipating green hydrogen or ammonia costs to be prohibitively high or you decide to bulldoze the fossil fuel plants rather than using them as part of a chemical storage system. Additionally if you are anticipating energy growth nuclear looks good in the short term (but after 60 years we're basically back at square one arguing about thermal pollution rather than CO2)