Technology

There will be diversity in the future grid, but that diversity will be in the forms of energy storage used. I think the grid of the future is almost entirely solar but with different energy storage systems optimized for different time scales. For storage on the order of seconds, you use fly wheels to replace the spinning mass once provided by gas turbines. For daily swings, vast warehouses full of old electric car batteries work well. For longer term storage, you can use chemical energy storage or flow batteries. Think making vast tanks of ammonia or methane. You use excess electricity in the summer, store it as chemical energy in vast tank farms, and then burn it or run it through a fuel cell in the winter.

Although, for seasonal variation, the most practical solution might be just to spam solar panels. It just depends on the price ratio of solar panel cost to storage cost. You could have a grid that just had so much solar deployed that it is able to cover energy demand even on cloudy winter days. You just flat out build that many panels. Maybe then in the summertime you're capable of producing 10x your normal power needs.

Seems wasteful, but this would just encourage a lot of very energy-intensive industries to become more seasonal. We have a farming season, why not an steal smelting season? Why not an AI model training season? Maybe for datacenters, the big runs are done during the summer when power is dirt cheap. Then the companies spend the winter planning next year's runs, etc. Or the extra power could be used to make synthetic fuels from CO2 pulled from the air. Maybe we never figure out how to make batteries good enough to power a trans-oceanic jumbo jet. But maybe we don't have to. You offer dirt cheap energy on a seasonal basis, and people will find uses for it eventually.