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Comment by jeffwass | Hacker News Reader

Thanks for that link, pretty illuminating.

For anyone curious, breakdown of US power generation in 2021 was (4200 TWh total):

  Coal : 22%
  Natural Gas : 38%
  Nuclear : 19%
  Hydroelectric : 6%
  Other Renewables : 14%

Curiously, hydroelectric power production has been flat for the past decade. Is that because we've already tapped out most places where hydro can be productive?

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There are also projects to tear out hydro dams, especially smaller ones, because they are ecologically destructive. So while huge dams may generate enough power to justify the ecological cost, a 1MW dam on some relatively minor river may not justify its existence and so it gets torn back out to enable the river to be restored. You can put a bunch of solar panels on malls and office blocks and make up a big chunk of that power without destroying a river, the malls and offices are already our fault because we put them there, so adding solar panels probably doesn't worsen the impact.

A lot of the small dams are also very old and would require a lot of money to keep them running so just tearing them down often turns out to be cheaper long term.

I found it most interesting that "Other Renewables" (i.e. solar and wind) went from ~5% to ~15% in just 10 years. If we can triple capacity again in the next 10 years, we could completely eliminate coal (assuming storage can solve load issues).

Two issues with hydro:

1) Most of the obvious places have dams already and building new dams is a combination of expensive and disruptive.

2) Droughts and water shortages make the existing hydro plants less productive. E.g. the hoover dam has some issues with that in recent years.

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