I could be wrong but I don't think hydro has a low enough spin-up time to be useful as a peaker plant.
With that said, these particular generators can be replaced with renewables and batteries trivially (and the costs are even more reasonable with the recent passing of the inflation reduction act) due to their smallish capacity (~200 acres of land for 20MW solar, small footprint for the storage system).
Renewables and batteries can be added trivially. I don't see how that means the dams should be torn down.
EDIT: I think, importantly, that these decisions should require the replacement of generation capacity lost with clean generation and storage as part of the cost benefit analysis.
This demolition happened in Oregon. Despite a growing population and increasingly hot summers, Oregon’s electricity use peaked in 2000. https://www.oregon.gov/energy/energy-oregon/Pages/How-Oregon...
US energy demand has been plateauing for a while as well: https://www.eia.gov/todayinenergy/detail.php?id=38572
However, electricity is very low on the utility provided by dams. Reducing flooding and stabilizing the water supply tend to be vastly more valuable in most areas.
Both are 'the future', and both will rather dramatically increase power grid demand.
Luckily, I think 'smart' pricing and demand scheduling will mean that the infrastructure changes will be minimal and gradual despite the massively increased demand - there won't be rolling blackouts or emergencies anytime soon.
That's a good reason.
My point is/was that that is unrelated to renewables and batteries.
California's system with dams near peaks of the Sierra Nevada range, feeding penstocks to thousands of meters below, is both massively more efficient and causes nowhere near the ecological damage of the river valley dams being torn down.
Those were largely built in the 1920s with pulley-operated (pre-hydraulics) equipment trailered up on abysmally bad roads... that still exist, unimproved.
You usually roughly follow the demand curve with hydro, coal and nuclear, fill in the gaps of their reaction time with gas (though preferably keeping the gas plant above their minimum load of ~40% during the day), and fill in the gaps of that mix with pumped hydro.
Now if you want to there's no real reason you can't outfit a dam like a pumped hydro plant instead of the setup of a baseload plant. After all pumped hydro is just a reservoir you refill manually when electricity is cheap.
1. https://www.siemens-energy.com/global/en/offerings/services/... 2. https://www.power-technology.com/analysis/featuredinorwig-a-...