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The issue with solar (and wind) is unstable generation profile, and need to overprivision a lot to compensate for worst-case scenario, e.g. cloudy windless Dece

The issue with solar (and wind) is unstable generation profile, and need to overprivision a lot to compensate for worst-case scenario, e.g. cloudy windless December (you can't have batteries this big). Usually the way to do it is solar/wind + natural gas plants, which usually shut off

kragen 2y ago
agreed! you can afford hours of batteries but not days or weeks. after looking for quite a while i found this nrel report on utility-scale battery storage system cost: https://atb.nrel.gov/electricity/2023/utility-scale_battery_storage https://atb.nrel.gov/electricity/2023/utility-scale_battery_... in theory, flow batteries and fuel cells could allow you to afford days or weeks of batteries, but the incentive to invest in those isn't there until the renewable transition is a lot further along. aluminum-air batteries are sort of like fuel cells that burn aluminum, which you could stockpile a lot of, and i think they could potentially be cheaper per watt than gas turbines. and iron-air batteries are another similar variant which can in fact be recharged my intuition is that gas turbines have a much higher power density than steam turbines because the temperature difference is greater and you don't need an external boiler. but i don't know if that works out to a lower cost per peak watt. do you have any idea?
- audunw 2y ago
  Many industrial countries already have lots of gas power plants. If they don’t actually need to run that often and don’t need that much fuel, just run them on hydrogen or biogas instead. Near zero investments to be made. Just somewhat larger operational costs per MWh delivered. If you collocate some industry that needs hydrogen (necessary for green steel and fertilisers for instance) then making and storing the hydrogen on-site should be fairly cost efficient. Running hydrogen in gas turbines has been demonstrated already btw.
  - kragen 2y ago
    right now only about a third of the 18 terawatts or so of world marketed energy consumption is electrical. to electrify the rest of the existing economy, we need to triple electrical generation capacity. since some of that new capacity will be intermittent sources like solar and wind (probably almost all of it) we also need to expand peaker plant or battery capacity, probably a lot, in order to supply essential uses that aren't amenable to demand response; the alternative is blackouts and deindustrialization if your peaker plants are gas turbines, running them less drives up their capex per megawatt hour delivered, so i'm interested in how much that capex is i agree that hydrogen is a plausible form of storage and can certainly be used for gas turbines

kragen 2y ago

agreed! you can afford hours of batteries but not days or weeks. after looking for quite a while i found this nrel report on utility-scale battery storage system cost: https://atb.nrel.gov/electricity/2023/utility-scale_battery_storage https://atb.nrel.gov/electricity/2023/utility-scale_battery_... in theory, flow batteries and fuel cells could allow you to afford days or weeks of batteries, but the incentive to invest in those isn't there until the renewable transition is a lot further along. aluminum-air batteries are sort of like fuel cells that burn aluminum, which you could stockpile a lot of, and i think they could potentially be cheaper per watt than gas turbines. and iron-air batteries are another similar variant which can in fact be recharged my intuition is that gas turbines have a much higher power density than steam turbines because the temperature difference is greater and you don't need an external boiler. but i don't know if that works out to a lower cost per peak watt. do you have any idea?

audunw 2y ago
Many industrial countries already have lots of gas power plants. If they don’t actually need to run that often and don’t need that much fuel, just run them on hydrogen or biogas instead. Near zero investments to be made. Just somewhat larger operational costs per MWh delivered. If you collocate some industry that needs hydrogen (necessary for green steel and fertilisers for instance) then making and storing the hydrogen on-site should be fairly cost efficient. Running hydrogen in gas turbines has been demonstrated already btw.
- kragen 2y ago
  right now only about a third of the 18 terawatts or so of world marketed energy consumption is electrical. to electrify the rest of the existing economy, we need to triple electrical generation capacity. since some of that new capacity will be intermittent sources like solar and wind (probably almost all of it) we also need to expand peaker plant or battery capacity, probably a lot, in order to supply essential uses that aren't amenable to demand response; the alternative is blackouts and deindustrialization if your peaker plants are gas turbines, running them less drives up their capex per megawatt hour delivered, so i'm interested in how much that capex is i agree that hydrogen is a plausible form of storage and can certainly be used for gas turbines