Should we go all in on nuclear energy?: Portfolio pragmatists
48.7 gigawatts
January 17, 2024. London, minus four Celsius. Sun set three hours earlier. Wind: 2 percent of installed capacity. Demand: 48.7 gigawatts. Gas turbines flat out. Nuclear at full output. Emergency demand response activated. Power imported from France via the Channel interconnector. France had power to spare. France always has power to spare.
We need the lights on at seven o’clock in January. Not in theory. Now.
Solar: zero watts after sunset. Wind: zero during a high-pressure system — which is, with elegant cruelty, the weather that produces the coldest temperatures. Battery storage: hours, not the days needed to bridge a winter anticyclone. Nuclear: flat constant baseload. Renewables: cheapest marginal kilowatt-hours in history when conditions cooperate. Gas: ramps in minutes. You need all three.
The boring answer
The pro-nuclear camp wants 70 percent nuclear. We like it. France began under conditions — state monopoly, no independent review, post-oil-shock public — that do not exist in democracies today.
The anti-nuclear camp wants 100 percent renewables. The math does not close. Not yet. A renewables-only grid requires four times current capacity plus storage for multi-day Dunkelflaute — the German term for a dark, windless spell when both solar and wind output collapse simultaneously — the scenario.
We want nuclear at 25-40 percent for baseload, renewables for bulk generation, gas as a bridge, and interconnectors between grids. Nobody writes manifestos about portfolio diversification. The grid is infrastructure. Infrastructure rewards not being interesting.
Every year the nuclear-versus-renewables argument continues is a year of gas burned that neither side wanted.
Where we concede ground: Our pragmatism is cowardice. The gap between 30 percent and the optimum gets filled by gas, and those emissions are on us.
What would change our mind: Either three countries building SMR fleets on time and budget, or grid storage reaching seven-day duration below $50/MWh.
Read the full synthesis: Should we go all in on nuclear energy?