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Comment by Manuel_D | Hacker News Reader

> They're not going to buy your daytime energy either when they can make their own DC power at $10-30/MW

Unless it's night time. Or cloudy. Or during the winter when the incidence of the sun reduces solar output. Again, this is why any plan that involves cutting power to mines, smelters, etc. needs to factor in the costs of shutting down these industries when renewables fail to produce energy.

> Then you might want to just stop and think about how you might go about storing energy if you have a pump and a reservoir on a hill or a water tower. Just ponder that one for a few seconds.

Right, except we just have to have a lake on a hill handy. Some places have it. Most do not.

Why don't we just use hydroelectricity for all of our power needs? Ditch nuclear, and ditch solar and wind. Just build dams. Problem solved.

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> Unless it's night time. Or cloudy. Or during the winter when the incidence of the sun reduces solar output. Again, this is why any plan that involves cutting power to mines, smelters, etc. needs to factor in the costs of shutting down these industries when renewables fail to produce energy.

So they'll buy your night time energy for the few hours a day when the wind farm they contracted with for less than your O&M costs isn't producing. Still doesn't help the nuclear operator pay the bills for the other 22 hours. Unless you're suggesting we ban people from supplying their own energy or making contracts with fully privately funded wind generators? Sounds pretty un-free to me.

> Why don't we just use hydroelectricity for all of our power needs? Ditch nuclear, and ditch solar and wind. Just build dams. Problem solved

You cited a need to store energy for moving water from a reservoir to where it is needed. Storing the amount of water you need to store but raise it up a little bit is a fairly well understood problem.

Blocking water with a dam is a well understood problem. Don't bother with wind nor solar nor nuclear nor storage. Just build dams, problem solved.

> Blocking water with a dam is a well understood problem

I feel like we still have some problems with dam building, because they keep failing. We struggle to get the building material (in particular, sand). Concrete is pretty awful in terms of CO2. Dams of all sizes cause problematic changes to the rivers they're on, and block flows of fish and other animals. Smaller low head weirs and dams kill humans.

Lots of time, money, and effort is going into removing smaller dams and low head weirs.

No need to have a tantrum just because you couldn't think of a way to claim every joule needed weeks long chemical battery storage.

We won't need any storage. We'll just get all of our electricity from dams. Since it's a well understood problem we can build them anywhere we want in any quantity.

Nah, wind and solar are cheaper and safer and don't take as long. We can use the existing dams for dispatchable power though. As well as CSP of which the unsubsidized LCOE has recently hit parity with O&M of nuclear and is plummeting. Throw in some thermal storage as well, that's safe.

Nope, hydroelectricity is about the same levelized cost of energy. Include storage costs and it's vastly cheaper: https://www.eia.gov/outlooks/aeo/pdf/electricity_generation....

Look at the countries that produce all or nearly all their electricity from renewables. It's dominated by hydroelectricity: https://en.wikipedia.org/wiki/List_of_countries_by_renewable...

And since it's a well understood problem we can just build it everywhere, in arbitrary quantities.

This is quite the tantrum to be having in response to being told that you don't need a nuclear reactor to pump water downhill. Was it really so earth shattering to your world view?

But you do need an alpine lake, with another body of water down below it to collect that water so it can be pumped back into the upper reservoir. The geography needed to built pumped storage is very specific. Simply saying that we can just build dozens of terawatt hours of pumped hydro is as nonsensical as saying we can just build more dams. Is that really so earth shattering to your world view?

You claimed that chemical storage is always necessary to pump municipal fresh water with VRE. I pointed out that this a perfect example of a dispatchable load because it is frequently already done with reservoirs and water towers and you had a tantrum and tried to straw man that as claiming all generation be backed by PHES.

Reservoir towers don't hold nearly enough water to be viable energy stores. You need a big alpine lake like this: https://en.m.wikipedia.org/wiki/Turlough_Hill

And you need a reservoir down below to receive the water as it passes through turbines otherwise you're waiting for rainfall to fill that upper reservoir up naturally.

The geographic conditions to make pumped hydro are far more constrained than you seem to think. Most water reservoirs for municipal water supplies don't have the elevation drop to be used for generation and they don't have the lower reservoir to capture and feed water back into the upper reservoir.

By some bizarre coincidence they hold exactly enough energy to move the water down the hill to its destination at the pressure specified whenthe tower was built. So weird how that happens. Almost as if heating and transporting water have been trivially dispatchable loads for centuries before electricity was used to do them at all.

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