Normally surplus electricity results in a curtailment of fossil sources.
This is use-it-or-lose-it. Should they just allow the river to flow and bypass the turbines?
There's a reason why hydroelectric plants and dams go together.
And they don't need it, because power-generating dams are generally only built in places that provide lots of downstream flow naturally, like the U.S. Pacific Northwest, or in places where a reservoir is already desired for other reasons (typically drinking water, navigation, and/or flood control).
Dams have the capacity to route downstream flow around some turbines to lower their generating capacity. It's not really accurate to think of that routed water as "wasted capacity," because that water would flow naturally even if the dam wasn't there.
The (amortized) cost of building out new supply is a major[0] part of the cost of electricity - this is why most big energy producers spend millions of dollars per year on energy efficiency incentives. Haven't you ever wondered why your power company will give you a $50 rebate on an EnergyStar dishwasher? Isn't it counter-intuitive that they would pay you to buy less energy, when they have excess? It's not because they're tree-huggers - it's because decreasing demand growth delays the day when they need to build a new plant to meet demand, which increases the profitability of the current plant enough to make those incentives cost-effective[1].
0: I can't find a good estimate and it varies by fuel type, but I rememeber an environmental engineer at a former job telling me it was about half. Look up "Levelized Cost of Electricity" for more info.
1: If you're not convinced, instead of demanding more details, I urge you to just stop and ask whether the proposition "There is a lot of excess energy production lying around which BTC miners can soak up without impacting everyone else very much" really passes the sniff test.
Doesn't California actually pay Arizona to offload their surplus energy?
http://www.energy.ca.gov/almanac/electricity_data/total_syst...
So the extra there is not really electricity you'd want to plan a crytocurrency operation around.
Otherwise you'd ruin a lot of machines depending on either 220V/110V or 50Hz being on the grid.
This argument also explicitly ignores schemes such as PoS that don't have this massive power drain, and also ignores interesting schemes like PoC (Proof of Capacity)[1] that also don't have this power drain (apparently).
there absolutely is a disbalance between energy produced and energy consumed. if we're lucky, there will be storage capacity nearby. we're mostly not lucky. ever heard of australia? or tesla? google some.
> wasted on useless cryptocurrencies
yeah, transferring value securely without trusting third parties is not useful at all. gotta run all those banks and employ all those bankers, because that costs no energy nor other resources.
are you a banker by any chance?