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This article:
Overbuilding solar at up to 4 times peak load yields a least cost all renewables grid.
I'm normally among those who think that renewable advocates lack realism when they advocate 100% wind+solar grid. This article is the first I've seen that comes close to being plausible. I do doubt the article's numbers for storage and for wind, but the basic idea of massively overbuilding solar is in the right direction.
The basic idea is this. Actual solar generation depends strongly on the season and the weather. But even on the worst case day (winter solstice, thick clouds, and heavy snowfall), solar panels produce a fraction of their rated power. If there is enough overcapacity, then even that fraction will be big enough to supply the demand on that day plus recharge the batteries for that night. No heroics, special tricks or cleverness are necessary. Simplicity and reliability are the keys to successful power.
The article says 400% overcapacity is enough. I say 800% for the sake of argument and to allow for contingencies like hurricanes and ice storms. That is roughly 8 Terrawatts for the USA. At $1/watt installed, that's $8 Terradollars investment we need for the generation part (plus ? for storage). That's nearly 40% of the pre-COVID USA GDP. Big numbers, but conceivable when spread over a number of years.
Side issues:
Terrestrial wind in some regions is subject to 2-4 consecutive weeks with winds <15 knots, so wind production would be nearly zero. That makes terrestrial wind overcapacity less attractive than solar overcapacity. Offshore wind is more dependable, and thus more attractive, but it is only close to the coastline by definition. This whole idea is much easier to visualize with solar.
Solar capacity could be distributed across the continent close to the load centers. Therefore, massive new investments in power transmission or distribution would not necessarily be needed with this change.
What to do with the massive solar overcapacity in summer? The article says "curtailment" meaning shut down portions so we don't generate energy that we can't use. But the excess capacity could be used to produce hydrogen or fresh water production by desalinization. Hydrogen and desalinization are not economical in most circumstances, but if the alternative is curtailment of excess capacity, we might reconsider their economy.
Others have proposed use rather than curtailment before, but they weren't thinking on the scale of 700% of peak demand. The economies of scale would be very significant.
The required overcapacity would be less in southern states than northern states. Fresh water is more scarce in southern states.
We already have the technology (called synthetic inertia) to make solar panels behave transiently like old fashioned steam turbine generators. That allows a non-disruptive transition with respect to grid operations and control. No matter what the ratio of solar to conventional generation, the dynamics of the grid would remain nearly constant.
Of course it would take lots of engineering to study the actual feasibility of this plan. Perhaps 50 engineering-man-years to do the study. If I was not retired, I would bid for the study contract myself I know exactly the team to do it. It is a study that I believe should be funded.
p.s. It's fun to have something other than COVID-19 to think about.
Overbuilding solar at up to 4 times peak load yields a least cost all renewables grid.
I'm normally among those who think that renewable advocates lack realism when they advocate 100% wind+solar grid. This article is the first I've seen that comes close to being plausible. I do doubt the article's numbers for storage and for wind, but the basic idea of massively overbuilding solar is in the right direction.
The basic idea is this. Actual solar generation depends strongly on the season and the weather. But even on the worst case day (winter solstice, thick clouds, and heavy snowfall), solar panels produce a fraction of their rated power. If there is enough overcapacity, then even that fraction will be big enough to supply the demand on that day plus recharge the batteries for that night. No heroics, special tricks or cleverness are necessary. Simplicity and reliability are the keys to successful power.
The article says 400% overcapacity is enough. I say 800% for the sake of argument and to allow for contingencies like hurricanes and ice storms. That is roughly 8 Terrawatts for the USA. At $1/watt installed, that's $8 Terradollars investment we need for the generation part (plus ? for storage). That's nearly 40% of the pre-COVID USA GDP. Big numbers, but conceivable when spread over a number of years.
Side issues:
Terrestrial wind in some regions is subject to 2-4 consecutive weeks with winds <15 knots, so wind production would be nearly zero. That makes terrestrial wind overcapacity less attractive than solar overcapacity. Offshore wind is more dependable, and thus more attractive, but it is only close to the coastline by definition. This whole idea is much easier to visualize with solar.
Solar capacity could be distributed across the continent close to the load centers. Therefore, massive new investments in power transmission or distribution would not necessarily be needed with this change.
What to do with the massive solar overcapacity in summer? The article says "curtailment" meaning shut down portions so we don't generate energy that we can't use. But the excess capacity could be used to produce hydrogen or fresh water production by desalinization. Hydrogen and desalinization are not economical in most circumstances, but if the alternative is curtailment of excess capacity, we might reconsider their economy.
Others have proposed use rather than curtailment before, but they weren't thinking on the scale of 700% of peak demand. The economies of scale would be very significant.
The required overcapacity would be less in southern states than northern states. Fresh water is more scarce in southern states.
We already have the technology (called synthetic inertia) to make solar panels behave transiently like old fashioned steam turbine generators. That allows a non-disruptive transition with respect to grid operations and control. No matter what the ratio of solar to conventional generation, the dynamics of the grid would remain nearly constant.
Of course it would take lots of engineering to study the actual feasibility of this plan. Perhaps 50 engineering-man-years to do the study. If I was not retired, I would bid for the study contract myself I know exactly the team to do it. It is a study that I believe should be funded.
p.s. It's fun to have something other than COVID-19 to think about.