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> I don't understand why people keep claiming that solar and wind are "cheap". It's simple: they're looking at the incremental cost of adding one more solar pa

by cesarb 3y ago

> I don't understand why people keep claiming that solar and wind are "cheap". It's simple: they're looking at the incremental cost of adding one more solar panel string or one more wind turbine, compared to generating that same amount of power with the already existing power plant mix. > The cost goes way up once you include enough storage and long-range transmission to maintain grid stability. That cost exists only if you for some reason insist on 100% solar and wind. If you keep already existing power plants (including gas and hydro), the cost to maintain grid stability is much lower. This can easily be shown to be the case in practice: a large portion of the solar and wind power in the world was added to the grid without adding any extra storage or long-range transmission, reducing the fuel costs (or water usage) of existing power plants but not replacing them. Having a 100% pure solar or 100% pure wind grid is an interesting thought experiment, to probe the limits of what's possible, but it's not very relevant in the real world except on remote areas where delivering fuel is expensive, connecting to a wider grid is not viable, and there's no hydraulic or geothermal alternative.

nradov 3y ago
I don't think you've actually done the math on that one. Keeping gas power plants online but unused except when renewables are unavailable is extremely expensive. We've been able to kind of ignore that up until now because of the limited scale of renewables generation but eventually the economics become untenable. Who is going to pay the large fixed costs to keep those gas plants on standby?
- theptip 3y ago
  > I don't think you've actually done the math on that one. Since you are implying that you _have_ done the math on this one, would you care to share links to analysis/modeling that backs up your position? I'm always open to being persuaded. Recently I have been citing https://emp.lbl.gov/utility-scale-solar/ https://emp.lbl.gov/utility-scale-solar/ for the claim "solar is cheap on the margin", and modeling like https://theconversation.com/up-to-90-of-electricity-from-solar-and-wind-the-cheapest-option-by-2030-csiro-analysis-151831 https://theconversation.com/up-to-90-of-electricity-from-sol..., https://reneweconomy.com.au/a-near-100-per-cent-renewables-grid-is-well-within-reach-and-with-little-storage/ https://reneweconomy.com.au/a-near-100-per-cent-renewables-g... for "storage isn't going to be too expensive for some time". To be clear I'm not making any particular case for how we cover the last 10% or so of demand, though I'd note that gas peakers are already a thing that are required to solve this problem, and yes they are expensive, but not unfeasibly so. My claim was it's cheap on the margin, right now. In a decade when we're closer to 100% it might start to get more expensive to replace the marginal % of generation with solar/wind. Nuclear doesn't help at all with the intra-day variable portion of the demand curve, it's just lower-variance so you don't need to worry about inter-day fluctuations. It seems that most of the time, a diverse blend of renewables averages out the inter-day variability so it's not clear to me exactly how much we need in storage to guard against "no wind / no sun" days. (Is this the mirror problem that we currently have, where a heat wave in TX means the mostly-not-renewable grid can't keep up? Sometimes we see outlier weather-related demand-supply mismatches, and spot pricing / demand shedding are typically how we respond to those outliers.) Over-provisioning wind and solar might still be cheaper than building nuclear and/or storage, or perhaps green hydrogen might be a better option. Or perhaps we keep some gas peakers around. For the intra-day variability we're already seeing lots of mixed-solar/battery being built (see the LBL report I linked above) which tends to be in the ballpark of load-shifting the generation 4 hours, which is most of what we need for intra-day gap between demand and solar peak production. This is still affordable vs running coal plants, and only going to get cheaper over time. Anyway, this isn't my field and I'm open to being persuaded, if you want to share some modeling that you think is better.

by cesarb 3y ago

nradov 3y ago

I don't think you've actually done the math on that one. Keeping gas power plants online but unused except when renewables are unavailable is extremely expensive. We've been able to kind of ignore that up until now because of the limited scale of renewables generation but eventually the economics become untenable. Who is going to pay the large fixed costs to keep those gas plants on standby?

theptip 3y ago
> I don't think you've actually done the math on that one. Since you are implying that you _have_ done the math on this one, would you care to share links to analysis/modeling that backs up your position? I'm always open to being persuaded. Recently I have been citing https://emp.lbl.gov/utility-scale-solar/ https://emp.lbl.gov/utility-scale-solar/ for the claim "solar is cheap on the margin", and modeling like https://theconversation.com/up-to-90-of-electricity-from-solar-and-wind-the-cheapest-option-by-2030-csiro-analysis-151831 https://theconversation.com/up-to-90-of-electricity-from-sol..., https://reneweconomy.com.au/a-near-100-per-cent-renewables-grid-is-well-within-reach-and-with-little-storage/ https://reneweconomy.com.au/a-near-100-per-cent-renewables-g... for "storage isn't going to be too expensive for some time". To be clear I'm not making any particular case for how we cover the last 10% or so of demand, though I'd note that gas peakers are already a thing that are required to solve this problem, and yes they are expensive, but not unfeasibly so. My claim was it's cheap on the margin, right now. In a decade when we're closer to 100% it might start to get more expensive to replace the marginal % of generation with solar/wind. Nuclear doesn't help at all with the intra-day variable portion of the demand curve, it's just lower-variance so you don't need to worry about inter-day fluctuations. It seems that most of the time, a diverse blend of renewables averages out the inter-day variability so it's not clear to me exactly how much we need in storage to guard against "no wind / no sun" days. (Is this the mirror problem that we currently have, where a heat wave in TX means the mostly-not-renewable grid can't keep up? Sometimes we see outlier weather-related demand-supply mismatches, and spot pricing / demand shedding are typically how we respond to those outliers.) Over-provisioning wind and solar might still be cheaper than building nuclear and/or storage, or perhaps green hydrogen might be a better option. Or perhaps we keep some gas peakers around. For the intra-day variability we're already seeing lots of mixed-solar/battery being built (see the LBL report I linked above) which tends to be in the ballpark of load-shifting the generation 4 hours, which is most of what we need for intra-day gap between demand and solar peak production. This is still affordable vs running coal plants, and only going to get cheaper over time. Anyway, this isn't my field and I'm open to being persuaded, if you want to share some modeling that you think is better.