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Seasonal variation in PV production is much much more than 4-7% in northern Europe. In the UK daylight hours vary between 8hrs in winter and 16.5hrs in summer (

Seasonal variation in PV production is much much more than 4-7% in northern Europe. In the UK daylight hours vary between 8hrs in winter and 16.5hrs in summer (more in Scotland), and on top of that winter has many more overcast days meaning you get a lot less irradiation during those hours. As a result, total irradiation in December is many multiples lower than that in June. Given that, it's not (currently) economically viable to build storage+PV on anything approaching the scale we would need to replace baseload generation completely.

pydry 3y ago
>Seasonal variation in PV production is much much more than 4-7% in northern Europe. 4-7% isn't seasonal variation in PV production. It's the amount of grid energy that needs to be supplied under a hypothetical 100% solar/wind/pumped storage grid when: * Solar output is low * and wind output is low * and ~8 hours of pumped storage is depleted. Obviously the wind blows at night and pumped storage works at night and electricity demand is lower at night. Obviously seasonal storage would not have to be tapped every night. >Given that, it's not (currently) economically viable to build storage+PV Why would that be given? It's categorically false. The opposite is true. Maybe what you meant to say was that "GIVEN 2GW of solar energy was being produced today" AND "coire glas is under construction" because it's highly economically viable, maybe we should lend a hand in the form of subsidies in scaling that up? Or did you want to push those subsidies to a form of energy with a 5x higher LCOE?
- tomatocracy 3y ago
  I'm not saying that Solar PV isn't economically viable at all (I've invested in Solar PV projects for my day job in fact, and obviously wouldn't have done so if I didn't think this). My concern is the "end game", where all current baseload generation gets disconnected from the grid (including current nuclear when it reaches end of life). Solar PV's current low LCOE doesn't help you a lot in that case because in order to actually deliver the energy needed at the right time you will need to do some combination of (1) build a lot more PV than "needed" and routinely curtail it significantly in summer (ie significantly derate nameplate capacity) and (2) build a lot more storage to deal with seasonal and other variations. This is when nuclear starts to look like it makes sense as part of the energy mix in my view.
  - pydry 3y ago
    I already addressed why it doesnt help above: >Nuclear power doesnt store energy. It will pump out 2GW all the time whether you need 6GW or you need 0GW. It doesn't really help in that respect at all because it can't be scaled up and down. It's not a peaker. i.e. nuclear power needs peakers or storage too. not as much as solar and wind but it still needs to be paired with peakers or storage. >build a lot more storage to deal with seasonal and other variations. This is what makes the most economic sense currently because pumped storage + hydrogen storage + solar + wind <<< nuclear power costs. Even IF you assumed nuclear power plants could be peakers (they can't) or that Fukushima/Chernobyl events had a probability of 0% (they dont), it would still not make any economic sense to build thrm when those 4 technologies can handle everything together at a much cheaper cost and can be built in 1/2 - 1/20th the amount of time.

pydry 3y ago

>Seasonal variation in PV production is much much more than 4-7% in northern Europe. 4-7% isn't seasonal variation in PV production. It's the amount of grid energy that needs to be supplied under a hypothetical 100% solar/wind/pumped storage grid when: * Solar output is low * and wind output is low * and ~8 hours of pumped storage is depleted. Obviously the wind blows at night and pumped storage works at night and electricity demand is lower at night. Obviously seasonal storage would not have to be tapped every night. >Given that, it's not (currently) economically viable to build storage+PV Why would that be given? It's categorically false. The opposite is true. Maybe what you meant to say was that "GIVEN 2GW of solar energy was being produced today" AND "coire glas is under construction" because it's highly economically viable, maybe we should lend a hand in the form of subsidies in scaling that up? Or did you want to push those subsidies to a form of energy with a 5x higher LCOE?

tomatocracy 3y ago
I'm not saying that Solar PV isn't economically viable at all (I've invested in Solar PV projects for my day job in fact, and obviously wouldn't have done so if I didn't think this). My concern is the "end game", where all current baseload generation gets disconnected from the grid (including current nuclear when it reaches end of life). Solar PV's current low LCOE doesn't help you a lot in that case because in order to actually deliver the energy needed at the right time you will need to do some combination of (1) build a lot more PV than "needed" and routinely curtail it significantly in summer (ie significantly derate nameplate capacity) and (2) build a lot more storage to deal with seasonal and other variations. This is when nuclear starts to look like it makes sense as part of the energy mix in my view.
- pydry 3y ago
  I already addressed why it doesnt help above: >Nuclear power doesnt store energy. It will pump out 2GW all the time whether you need 6GW or you need 0GW. It doesn't really help in that respect at all because it can't be scaled up and down. It's not a peaker. i.e. nuclear power needs peakers or storage too. not as much as solar and wind but it still needs to be paired with peakers or storage. >build a lot more storage to deal with seasonal and other variations. This is what makes the most economic sense currently because pumped storage + hydrogen storage + solar + wind <<< nuclear power costs. Even IF you assumed nuclear power plants could be peakers (they can't) or that Fukushima/Chernobyl events had a probability of 0% (they dont), it would still not make any economic sense to build thrm when those 4 technologies can handle everything together at a much cheaper cost and can be built in 1/2 - 1/20th the amount of time.