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> but there will be times when the sun isn't shining and the wind isn't blowing so you need to be able to meet energy demands in those cases. The only clean sol

by jhgb 5y ago

> but there will be times when the sun isn't shining and the wind isn't blowing so you need to be able to meet energy demands in those cases. The only clean solution is nuclear (and hydro where available). That claim is highly debatable. Lots of people claim that the storage necessary to overcome these generation troughs make it infeasible but they seem to completely ignore holistic cost minimization approaches using overgeneration and then conclude that the amount of storage required makes it impossible. Meanwhile it's been calculated that modest overgeneration squashes storage amounts (and costs) in massive ways. People have actually studied these things, you know... See for example the 2018 article On the economics of electrical storage for variable renewable energy sources by Zerrahn et al.

politician 5y ago
We can't assume overgeneration will be sustainable since there is profit to be made by idling or scrapping generators to reduce costs.
- jhgb 5y ago
  We can safely assume that. First, if the deployed mixture of generators is the cheapest mixed solution devised, there's money to be wasted "by idling or scrapping generators", since by definition that would increase costs, not reduce them, so it would be an irrational step to make. Second, opportunistic consumers not included in the base load can take advantage of these peaks, to the benefit of both sides (generators AND consumers -- consumers get power for peanuts and generators get some extra money they otherwise wouldn't get), for example for charging BEVs on demand -- and you'll need lots of power for that.
  - politician 5y ago
    Are you assuming grid-scale storage exists and is deployed widely in your scenario?
throwaway894345 5y ago
It's not like overgeneration is free either, and I'm very skeptical that overgeneration can squeeze blood from a stone on regionally cloudy, still weeks; however, I'll read your source when I have a free moment, thanks for sharing, etc.
- jhgb 5y ago
  Nobody says that overgeneration is free. But for example if your wind power costs are $20/MWh and your nuclear power costs are $80/MWh, even 100% overgeneration capacity for wind is still cheaper compared to the nuclear alternative. And if it achieves the desired effect cheaper than storage, then it will be preferred over storage as well. The optimal ratio of storage and overgeneration needs to be modeled for every grid independently; I believe the article I mentioned models it for the German grid. In practice, though, I expect that you won't even get energy waste from overgeneration if flexible energy consumers like BEVs or flexible hydrogen electrolyzers are connected to the grid. These will account for a major portion of electricity consumption and it will be possible to move their consumption around very considerably.
  - throwaway894345 5y ago
    I agree with your first paragraph, but I’m still far from optimistic that the cost analysis will work out in favor of renewables in the near term unless perhaps we continue to keep nuclear costs artificially high. In particular, I’m not sure that 100% over provisioning (absent storage) gets us anywhere near the same reliability of nuclear.
jjk166 5y ago
It doesn't matter how many solar panels you build, when the sun is down none of them are generating power. Likewise when the wind stops, it doesn't matter how many turbines are in the windfarm. Overgeneration certainly does not squash storage amounts.
- ben_w 5y ago
  It reduces but does not eliminate storage. You’ll still have some windless nights, but enough overproduction means that you don’t have to worry about mere cloudy days or low-wind periods — One suggestion in another comment was needing weeks of storage, and overproduction can reduce that to a day of storage, perhaps even less.
blitzar 5y ago
The solution will inevitably be distributed overstorage rather than overgeneration. 10% of everyones car and home battery will be annexed by the grid when needed.

by jhgb 5y ago

politician 5y ago

We can't assume overgeneration will be sustainable since there is profit to be made by idling or scrapping generators to reduce costs.

jhgb 5y ago
We can safely assume that. First, if the deployed mixture of generators is the cheapest mixed solution devised, there's money to be wasted "by idling or scrapping generators", since by definition that would increase costs, not reduce them, so it would be an irrational step to make. Second, opportunistic consumers not included in the base load can take advantage of these peaks, to the benefit of both sides (generators AND consumers -- consumers get power for peanuts and generators get some extra money they otherwise wouldn't get), for example for charging BEVs on demand -- and you'll need lots of power for that.
- politician 5y ago
  Are you assuming grid-scale storage exists and is deployed widely in your scenario?

throwaway894345 5y ago

It's not like overgeneration is free either, and I'm very skeptical that overgeneration can squeeze blood from a stone on regionally cloudy, still weeks; however, I'll read your source when I have a free moment, thanks for sharing, etc.

jhgb 5y ago
Nobody says that overgeneration is free. But for example if your wind power costs are $20/MWh and your nuclear power costs are $80/MWh, even 100% overgeneration capacity for wind is still cheaper compared to the nuclear alternative. And if it achieves the desired effect cheaper than storage, then it will be preferred over storage as well. The optimal ratio of storage and overgeneration needs to be modeled for every grid independently; I believe the article I mentioned models it for the German grid. In practice, though, I expect that you won't even get energy waste from overgeneration if flexible energy consumers like BEVs or flexible hydrogen electrolyzers are connected to the grid. These will account for a major portion of electricity consumption and it will be possible to move their consumption around very considerably.
- throwaway894345 5y ago
  I agree with your first paragraph, but I’m still far from optimistic that the cost analysis will work out in favor of renewables in the near term unless perhaps we continue to keep nuclear costs artificially high. In particular, I’m not sure that 100% over provisioning (absent storage) gets us anywhere near the same reliability of nuclear.

jjk166 5y ago

It doesn't matter how many solar panels you build, when the sun is down none of them are generating power. Likewise when the wind stops, it doesn't matter how many turbines are in the windfarm. Overgeneration certainly does not squash storage amounts.

ben_w 5y ago
It reduces but does not eliminate storage. You’ll still have some windless nights, but enough overproduction means that you don’t have to worry about mere cloudy days or low-wind periods — One suggestion in another comment was needing weeks of storage, and overproduction can reduce that to a day of storage, perhaps even less.

blitzar 5y ago

The solution will inevitably be distributed overstorage rather than overgeneration. 10% of everyones car and home battery will be annexed by the grid when needed.