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Comment by nostromo | Hacker News Reader

Solar and wind are great when it’s sunny or windy. We need dams for green energy the rest of the time.

Comparing max wind capacity to actual outputs from dams is nonsensical. Wind typically produces 30% or less of its max capacity over any period of time and it does so unreliably. The energy from damns is much more valuable.

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You'd have a point if someone were proposing to demolish the Grand Coulee Dam, which generates 6.8 terawatts, or Hoover Dam, which generates a little over 2 terawatts, but that just isn't what's happening here. Removing the Elwha River dams reduced Washington State's hydroelectric capacity by a whopping 0.09%, and removing the four Klamath River dams will reduce California's hydro capacity by 0.76%. These are minor rural dams built a century ago, when the long-distance grid was not what it is today, and they simply do not matter anymore.

1. Your reply to parent said dams’ output is small

2. parent refutes the data

3. You reply again with same message

Can you address the parent’s concern that the data you’re reporting is incorrect? (Solar metrics are based on max / theoretical output and not real output)

Parent did not refute the data, parent said they did not care that a vastly greater quantity of renewables were being installed than the hydro capacity being removed, due to concerns about capacity factor. My second comment therefore showed that the hydro capacity being removed is insignificant relative to hydro alone, without reference to other renewables.

“Comparing max wind capacity to actual outputs from dams is nonsensical. Wind typically produces 30% or less of its max capacity over any period of time and it does so unreliably. The energy from damns is much more valuable.”

Still absolute amount is a factor. A small river dam with 0.09% power can absolutely not be worth it if it is old, in the wrong spot, has huge detrimental effects on downstream areas etc. Everything has to be taken into account.

Sure hydro powers well with wind and solar, but a dam can still be overall a bad thing. And I say this as a guy who grew up next to a dam which is one of 12 dams on that river and I don't have a problem with any single one of them.

Building structures that guide rivers is never a thing where the thing you did decades ago will turn out to be the most clever, most efficient and environmentally best solution. That means people who live with and around rivers have to be able to adapt their plans to what they learned. And sometimes that means realizing a particular dam in a particular place does more harm than good, while this is the polar opposite for some other structure.

The person you quote was mistaken; I cited nameplate capacity, not production output, for both hydro and wind. (My wording could have been clearer.) Furthermore, capacity factors are almost identical: US wind production in 2022 was 35.9% of capacity, while the corresponding figure for hydro was 36.3%.

> Solar and wind are great when it’s sunny or windy. We need dams for green energy the rest of the time.

Dams rely on rainfall and snowmelt to generate power. They are not magically immune from yearly or seasonal variance, and in fact they are quite susceptible to climate change as precipitation patterns shift.

In addition I see no studies or cited research about how many birds were killed by the increase of wind power, or other environmental impacts that the massive increase in wind turbines may have caused.

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