> the problem is solar is cheaper, so its profitable for someone to build 50MW of solar.
That's not how that works. The unit cost of generation is inconsequential compared to the fixed cost, so you don't stop generating at any point and you just take the market price whatever it is.
Suppose nuclear needs to average $10/MWh to meet costs but solar can do $8/MWh during the day. Then as long as nuclear can get $12/MWh at night, it can match solar on price during the day and still cover costs. And solar + storage can't beat $12/MWh at night while the storage costs much more than $4/MWh. So then it's unprofitable to build the other 25MW in solar capacity because it would only get undercut on price during the day by nuclear which can make up the difference at night.
And it's the same thing for wind or anything else. Once you have 25GW of nuclear generation, nobody is ever going to be able to undercut it on marginal cost -- they'll never stop generating power and selling it for the market price, even if it would cause the plant operators to yield negative overall returns, because selling for an unprofitable market price is still less of a loss than getting nothing. And since everyone knows that ahead of time they don't bother to build a bunch of unprofitable wind turbines and that doesn't happen to begin with.
> If it takes you 5 years to build the 25MW of solar, but the nuclear takes 15 years, theres a 10 year gap between solar build out finishing and nuclear being ready to take over from that coal plant. What do you do? 10 years of burning coal? or continue building solar so your covering as much demand as you can? But then why retire all that solar when the nuclear plant comes online?
There is no hope of replacing the entire grid with solar in five years time. The production capacity for that doesn't exist, and would be unprofitable to create because once you've replaced the entire grid with solar all those new panel factories you just paid to build would go idle.
What actually happens is that you add solar as fast as you can and it's still not enough, and you add nuclear at the same time and if we're lucky then together they're enough.
That's not how that works. The unit cost of generation is inconsequential compared to the fixed cost, so you don't stop generating at any point and you just take the market price whatever it is.
Suppose nuclear needs to average $10/MWh to meet costs but solar can do $8/MWh during the day. Then as long as nuclear can get $12/MWh at night, it can match solar on price during the day and still cover costs. And solar + storage can't beat $12/MWh at night while the storage costs much more than $4/MWh. So then it's unprofitable to build the other 25MW in solar capacity because it would only get undercut on price during the day by nuclear which can make up the difference at night.
And it's the same thing for wind or anything else. Once you have 25GW of nuclear generation, nobody is ever going to be able to undercut it on marginal cost -- they'll never stop generating power and selling it for the market price, even if it would cause the plant operators to yield negative overall returns, because selling for an unprofitable market price is still less of a loss than getting nothing. And since everyone knows that ahead of time they don't bother to build a bunch of unprofitable wind turbines and that doesn't happen to begin with.
> If it takes you 5 years to build the 25MW of solar, but the nuclear takes 15 years, theres a 10 year gap between solar build out finishing and nuclear being ready to take over from that coal plant. What do you do? 10 years of burning coal? or continue building solar so your covering as much demand as you can? But then why retire all that solar when the nuclear plant comes online?
There is no hope of replacing the entire grid with solar in five years time. The production capacity for that doesn't exist, and would be unprofitable to create because once you've replaced the entire grid with solar all those new panel factories you just paid to build would go idle.
What actually happens is that you add solar as fast as you can and it's still not enough, and you add nuclear at the same time and if we're lucky then together they're enough.