Comment by PaulHoule

This report, which is often quoted,

https://www.eia.gov/analysis/studies/powerplants/capitalcost...

gives a crazy low cost for a solar + battery plant that assumes storage for an hour and a half which is certainly too little. When I split out their generation and storage numbers and put in the assumption that 12 hours of storage gets you through the night the price is getting in the same range as gas turbine power plants.

There's the seasonal problem too, the answer to that is some combination of building more solar capacity or adding huge amounts of storage. I'd estimate that the daily insolation varies by a factor of 2 or so in NY

https://www.solarenergylocal.com/states/new-york/new-york/

so you could build maybe twice the solar capacity and have enough generation in the winter. Judged that way the system cost is creeping in the direction of what nuclear energy costs, though you've got a lot of "free" electricity in the summer although that could be "free as in puppy". Hypothetically you could do something like desalinate seawater and pump it uphill into reservoirs but operating any kind of industrial factory intermittently is going to be murder for capital and operating costs. There is this idea

https://www.moderndescartes.com/essays/factobattery/

where you could smooth out diurnal variation in a "hydrogen economy" factory by overbuilding electrolyzers, but to take advantage of "free" summer electricity you might have to lay off all your workers half the year not to mention building surplus transmission infrastructure.

Of course it takes detailed modeling of supply and demand to get good cost estimates for renewable plus storage systems and one thing I find irksome about that EIA report is that it quotes one number for a solar energy plant which is just wrong because the exact same solar plant will product a lot more power in Nevada and it will in Wisconsin. Many people are quoting these numbers and not really aware that they are discrediting themselves and the renewable energy cause because quoting a number that doesn't depend on time and place just violates common sense.