[jp191919]

I wonder why existing hydro isn't utilized to it's potential. For instance, the Grand Coulee Dam has the highest capacity of any power station in the US of almost 7 MW but usually puts out about a third of that.

[dec0dedab0de]

Niagra falls doesn't run at full capacity because it takes away from the attraction of the falls themselves, and tourism is important there. They turn up capacity after hours, and the falls slow down.

[iracigt]

Not only that, they use the gravitational potential of the falls to store massive amounts of energy when there's a surplus. Way cheaper to hold or even pump the water back up to the reservoir at the top than build lithium batteries. So yeah, as a local, can confirm they turn Niagara Falls (partially) off at night. Thanks to the Falls and several nuclear plants on Lake Ontario, Upstate NY and Southern Ontario have some of the lowest carbon electricity in the countries. Quebec is even better with basically all of their power coming from hydro.

See also https://en.wikipedia.org/wiki/International_Control_Dam

[willturman]

Lake Powell behind Glen Canyon Dam is currently at 23.6% of capacity. Lake Mead behind Hoover Dam is currently at 29.7% of capacity.

Given the current state of the Upper Colorado River basin snow pack, there is a not-insignificant chance that Lake Powell will recede below a minimum power generating level by the end of this year for the first time ever.

[ceejayoz]

It turns out that "releasing immense amounts of water downstream" can have side effects.

[ikawe]

What do you think is happening to the water not being utilized in the production of power? I assumed it's still being run downstream, just not through the power producing turbines.

I'd expect there's not a big effect on the ultimate amount of water being released downstream either way.

[richardubright]

Looking at the data for lake that goes through the dam, it seems like they keep it at the same level. So it probably CAN make 7MW with more flow, but generally only flows at a state that puts out 2.

[lazide]

There is no way it’s max is 7MW. They likely meant 7GW.

7MW is the amount of power you can get from a couple of diesel gensets, waaaay smaller than even a small power plant

[https://www.cat.com/en_US/products/new/power-systems/electri...]

[jp191919]

I looked into this more, and there is quite a bit of seasonal variability to contend with as well.

[716dpl]

Limited water resource. In recent drought years, gas-fired power plants in California had to make up for reduced hydro generation.

[SigmundA]

https://en.wikipedia.org/wiki/Capacity_factor

[ViewTrick1002]

They are used as dispatchable sources. Capture value by being able to provide enormous amounts of power when needed compared to the watershed flow.

[bob1029]

Vogtle is probably producing the most electricity out of any generating plant in the US once you consider capacity factor.

[bryanlarsen]

Vogtle is also the most expensive electricity in the world, the only electricity costing more than $10,000 per kW.