5 ms·

Most life-cycle estimations argue that solar itself has a higher carbon footprint than nuclear. Solar+storage would be worse. The rationale behind it is simple

by mrpopo 7y ago

Most life-cycle estimations argue that solar itself has a higher carbon footprint than nuclear. Solar+storage would be worse. The rationale behind it is simple physics. Enriched nuclear fuel is the most energy-dense material we can access, so unless a new fundamental law is discovered, nuclear energy will have the best EROI, e.g. require the least energy overall to be produced (also note that most of the energy deployed is for security reasons). EDIT: another option for solar+storage to tend towards 0 residual carbon footprint is a life duration 10 or 100 times longer. Something to consider.

godelski 7y ago
> Most life-cycle estimations argue that solar itself has a higher carbon footprint than nuclear. Solar+storage would be worse. I'm going to add some nuance. As far as I'm aware, this is only true for photovoltaic solar. My understanding is that concentrated solar (mirrors heat up water tank and you have a steam turbine) has lower lifetime emissions than nuclear. That being said, storage does have a heavy footprint that many ignore. This is a harder number to accurately measure the impact, but if we're talking about a sane fully renewable system you have to have a lot of storage. Places like Southern California can get away with a day or two's worth of storage because there is little variation in conditions. But if you travel up the coast 500 miles things get drastically different. Even more so as you get into Washington. You're going to have to have at least a week's worth of storage. Same thing for the east coast. That said, these options are still better than coal. It is debatable if we're talking about coal + CCS though and likely doesn't beat gas + CCS. Though the counter argument to this is CCS in the manufacturing of your solar and batteries. Again, gets tricky and there's factors to include like tearing down existing coal and gas plants. TLDR: this problem is unsurprisingly extremely complicated even though we make it out to not be.
- billti 7y ago
  Could a highly efficient grid solve the "local weather" problem? While it might be cloudy in Washington, at the same time it's likely sunny in Nevada, or Texas, (or Mexico if you had cross border production), etc.. The broader the area you can depend on, the less you need "bad weather backup" systems.
  - godelski 7y ago
    Potentially. But there's a big if and quite a few drawbacks. If our power is dependent on such long range travel there is a lot more opportunity for failure. Since we're talking about power, this does mean both lives and millions to billions of dollars worth of economic activity. There's various reasons things could go down. A bird. Russia hacking our grid. Joe Schmoe crashes his truck. You name it. The only way to reduce two of these events is to build a large and complex network with many fail-safes, but that makes the second possibility easier. But if it goes down in Texas we're talking about Northern California, Oregon, and Washington potentially losing power. Having local sources of power is highly reliable and contains disasters to only be local. While I do believe we should have smarter grids there is much wanting in using this as a solution to the regional issues of renewable efficiencies and storage requirements.
  - cycomanic 7y ago
    The answer is yes, there have been studies about this for the US. I'm on mobile now but will try to dig this up later
readams 7y ago
nit: while this is true you cannot pick up enriched nuclear fuel off the ground. You have to process many tons of ore. Overall it's still better but this is not guaranteed by simply the energy density of fuel rods.
- mrpopo 7y ago
  Absolutely, and uranium mining will require more energy over time, as the best sources get depleted. Still, AFAIU, 1) the mining is not the largest energy requirement (security enforcement measures and refining require much more energy and infrastructure) 2) In the golden age of nuclear, it was commonly thought that we would have breeder reactors by now, that would make the fuel processing hundreds of times more efficient, and thus the question would be obsolete... Unfortunately, only India and Russia are still actively working on that technology.

by mrpopo 7y ago

godelski 7y ago

> Most life-cycle estimations argue that solar itself has a higher carbon footprint than nuclear. Solar+storage would be worse. I'm going to add some nuance. As far as I'm aware, this is only true for photovoltaic solar. My understanding is that concentrated solar (mirrors heat up water tank and you have a steam turbine) has lower lifetime emissions than nuclear. That being said, storage does have a heavy footprint that many ignore. This is a harder number to accurately measure the impact, but if we're talking about a sane fully renewable system you have to have a lot of storage. Places like Southern California can get away with a day or two's worth of storage because there is little variation in conditions. But if you travel up the coast 500 miles things get drastically different. Even more so as you get into Washington. You're going to have to have at least a week's worth of storage. Same thing for the east coast. That said, these options are still better than coal. It is debatable if we're talking about coal + CCS though and likely doesn't beat gas + CCS. Though the counter argument to this is CCS in the manufacturing of your solar and batteries. Again, gets tricky and there's factors to include like tearing down existing coal and gas plants. TLDR: this problem is unsurprisingly extremely complicated even though we make it out to not be.

billti 7y ago
Could a highly efficient grid solve the "local weather" problem? While it might be cloudy in Washington, at the same time it's likely sunny in Nevada, or Texas, (or Mexico if you had cross border production), etc.. The broader the area you can depend on, the less you need "bad weather backup" systems.
- godelski 7y ago
  Potentially. But there's a big if and quite a few drawbacks. If our power is dependent on such long range travel there is a lot more opportunity for failure. Since we're talking about power, this does mean both lives and millions to billions of dollars worth of economic activity. There's various reasons things could go down. A bird. Russia hacking our grid. Joe Schmoe crashes his truck. You name it. The only way to reduce two of these events is to build a large and complex network with many fail-safes, but that makes the second possibility easier. But if it goes down in Texas we're talking about Northern California, Oregon, and Washington potentially losing power. Having local sources of power is highly reliable and contains disasters to only be local. While I do believe we should have smarter grids there is much wanting in using this as a solution to the regional issues of renewable efficiencies and storage requirements.
- cycomanic 7y ago
  The answer is yes, there have been studies about this for the US. I'm on mobile now but will try to dig this up later

readams 7y ago

nit: while this is true you cannot pick up enriched nuclear fuel off the ground. You have to process many tons of ore. Overall it's still better but this is not guaranteed by simply the energy density of fuel rods.

mrpopo 7y ago
Absolutely, and uranium mining will require more energy over time, as the best sources get depleted. Still, AFAIU, 1) the mining is not the largest energy requirement (security enforcement measures and refining require much more energy and infrastructure) 2) In the golden age of nuclear, it was commonly thought that we would have breeder reactors by now, that would make the fuel processing hundreds of times more efficient, and thus the question would be obsolete... Unfortunately, only India and Russia are still actively working on that technology.