[powcontech]

While dams certainly store energy I wonder how many actually have flexibility to change their output by 80% of rated capacity or more on the same timescales that wind and solar output can vary.

I imagine there are a lot of environmental restrictions to keep the river flowing, avoid dewatering habitat for fish and otherwise impacting the ecosystem, and also supplying water to downstream users like farms and cities. Can’t stop the river completely!

[hedora]

As I understand it, some hydro plants have a second, smaller reservoir downhill from the dam. It absorbs water from surge production, and even allows the water to be pumped back uphill.

[noselasd]

you can switch turbines on and off , leading water to a turbine or a bypass in minutes

[powcontech]

You can, but I wonder do the operating conditions of the river actually allow it for a great number of plants? Or are they hemmed in by needing to always have a certain flow in the river plus/minus 10%.

[noselasd]

Usually they require a certain flow, the flow will be the same whether it goes through a turbine or bypass ofc.