Share of the total grid is meaningless comparing solar to nuclear. It’s the wrong metric to optimize for - the metric that actually matters and is the expensive one is reliability.
What matters is “share of the grid when solar literally cannot provide the power at any price”.
In a well designed and functional grid share of nuclear power should be close to 100% of the latter and the lowest percentage of the former you can get away with.
It’s better to think of nuclear as energy storage with a really really long lasting battery that costs the same to run it 24/7 or 1 hour a month.
Ideally it would be replacing close to all baseload/reliable power on the grid outside of hydro - with hydro being your peakers instead of natural gas for topologies amenable to it. The power share graph should look like nuclear at close to 100% at night less wind and battery storage that backs wind unreliability - and that graph remaining flat throughout the peak daytime hours with other energy sources kicking in such as solar, hydro, duck curve sized battery arrays, etc.
No one pays you for that reliability though. In free energy markets they pay you for what you supply, at the clearing price at that moment.
Solar is so cheap it will push nukes off the grid during the day, you don’t get credit just because it’s more reliable. People will just build more and more solar till the nukes share in the day is zero. And at night people are incentivized to build more wind and batteries, because you can still undercut the expensive nuke power and push it off. When the wind doesn’t blow at night there’s gas and hydro peakers. And more and more batteries. There’s increasingly no room left for nukes that have to be sold at 100% for 100% of the time to still be the most expensive form of energy.
The only way nukes have a role at scale today is if you have state intervention in the market to force the grid to buy your nuke power at close to 100% at the baseline share you described, because you have a nation-state goal of reliability that you prioritize higher than cost. Essentially subsidizing the nukes. And I’m sympathetic to that goal, but that’s not mostly not what western markets do, and not what they will do. Making power deliberately more expensive is unpopular, and not neoliberal marketism
What matters is “share of the grid when solar literally cannot provide the power at any price”.
In a well designed and functional grid share of nuclear power should be close to 100% of the latter and the lowest percentage of the former you can get away with.
It’s better to think of nuclear as energy storage with a really really long lasting battery that costs the same to run it 24/7 or 1 hour a month.
Ideally it would be replacing close to all baseload/reliable power on the grid outside of hydro - with hydro being your peakers instead of natural gas for topologies amenable to it. The power share graph should look like nuclear at close to 100% at night less wind and battery storage that backs wind unreliability - and that graph remaining flat throughout the peak daytime hours with other energy sources kicking in such as solar, hydro, duck curve sized battery arrays, etc.