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If you made all the alternatives also pay to capture their carbon cost, I think nuclear would be very competitive. Obviously it blows fossil fuels out of the w

If you made all the alternatives also pay to capture their carbon cost, I think nuclear would be very competitive. Obviously it blows fossil fuels out of the water, but hydroelectric also uses huge amounts of concrete, and IIRC the energy return on investment (MWh you get out per MWh it takes to construct) for solar and wind is quite poor and so I'd expect that to take a while to pay off too.

Retric 4y ago
Nuclear has a vastly worse EROI than grid PV solar. Nuclear lasts longer which somewhat offsets construction costs, but needs a vast workforce continually and a maintenance and power simply to operate. As a sanity check, sub 2c/KWh solar can’t require that much energy simply because energy costs money. Nuclear on the other hand ends up having ~1,000 workers drive somewhere for 50 years which also takes energy, but that’s often ignored. That said, people love to come up with all kinds of irrelevant comparisons using vastly outdated data to make things look worse for solar while ignoring Nuclear’s downsides. For example France’s capacity factor fell below 70% when they tried to ramp up production and things would look even worse on a 100% nuclear grid.
- cinntaile 4y ago
  It seems highly unlikely that grid PV solar has a higher EROI than nuclear and I can't find anything that supports this either (I find plenty of graphs supporting the opposite).
  - Schroedingersat 4y ago
    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.
  - Retric 4y ago
    You can easily come up with some wildly different numbers but … 2013 Meta analysis puts nuclear at 14:1 EROI. https://www.sciencedirect.com/science/article/pii/S0301421513003856 https://www.sciencedirect.com/science/article/pii/S030142151... You can find numbers all over the place for solar here’s something back in 2015 that goes as high as 34.2 : 1 depending on design and location: https://www.sciencedirect.com/science/article/abs/pii/S136403211500146X?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S13640... and of course the best numbers have improved dramatically over the last 7 years. At the other end, Solar in Alaska obviously has much worse numbers. It’s really interesting how much you can twist these numbers. For example the electricity to run equipment like pumps, computers etc at a nuclear power plant. It’s easy to call them as an input when the power plant is offline, but during operation are they actual cost or should the be treated as an inefficiency where only the external inputs count.
    - cinntaile 4y ago
      Yeah while EROI is supposed to be some sort of objective value, it is of course extremely sensitive to the data you put in. It is hard to even agree on what to include and where to draw the system boundaries. LCA suffers from the same issue but I do feel like EROI gets abused more for ideological purposes than LCA, I think LCA as a concept is a bit more robust by now. I mean this in a general sense, I'm not pointing fingers here.

Retric 4y ago

Nuclear has a vastly worse EROI than grid PV solar. Nuclear lasts longer which somewhat offsets construction costs, but needs a vast workforce continually and a maintenance and power simply to operate. As a sanity check, sub 2c/KWh solar can’t require that much energy simply because energy costs money. Nuclear on the other hand ends up having ~1,000 workers drive somewhere for 50 years which also takes energy, but that’s often ignored. That said, people love to come up with all kinds of irrelevant comparisons using vastly outdated data to make things look worse for solar while ignoring Nuclear’s downsides. For example France’s capacity factor fell below 70% when they tried to ramp up production and things would look even worse on a 100% nuclear grid.

cinntaile 4y ago
It seems highly unlikely that grid PV solar has a higher EROI than nuclear and I can't find anything that supports this either (I find plenty of graphs supporting the opposite).
- Schroedingersat 4y ago
  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.
- Retric 4y ago
  You can easily come up with some wildly different numbers but … 2013 Meta analysis puts nuclear at 14:1 EROI. https://www.sciencedirect.com/science/article/pii/S0301421513003856 https://www.sciencedirect.com/science/article/pii/S030142151... You can find numbers all over the place for solar here’s something back in 2015 that goes as high as 34.2 : 1 depending on design and location: https://www.sciencedirect.com/science/article/abs/pii/S136403211500146X?via%3Dihub https://www.sciencedirect.com/science/article/abs/pii/S13640... and of course the best numbers have improved dramatically over the last 7 years. At the other end, Solar in Alaska obviously has much worse numbers. It’s really interesting how much you can twist these numbers. For example the electricity to run equipment like pumps, computers etc at a nuclear power plant. It’s easy to call them as an input when the power plant is offline, but during operation are they actual cost or should the be treated as an inefficiency where only the external inputs count.
  - cinntaile 4y ago
    Yeah while EROI is supposed to be some sort of objective value, it is of course extremely sensitive to the data you put in. It is hard to even agree on what to include and where to draw the system boundaries. LCA suffers from the same issue but I do feel like EROI gets abused more for ideological purposes than LCA, I think LCA as a concept is a bit more robust by now. I mean this in a general sense, I'm not pointing fingers here.