Comment by Panzer04
11 hours ago
It's not quite as bad as that, since you don't consume fossil fuel resources when plants aren't running, but this is mostly a benefit for oil/gas plants, not coal (since the coal is likely useless without the power plant consumer anyway)
Depending on the type of power plant, it can take quite a while to spin up (or down) one of them and get them to optimal power production.
https://www.eia.gov/todayinenergy/detail.php?id=45956
If you shut down by day, it can take multiple hours for it to be able to provide full load... and multiple hours for it to shut down cleanly. During this time it is producing power at less than optimal rates and/or using the fossil fuels to keep the wheels spinning and in sync with the grid so that they don't have to go through a phase matching period.
(aside for coal - note that it takes more than 12 hours for a coal plant to get running from a cold start)
That's not really a problem. A spin up over a couple hours matches nicely with the slow sunset over a continent. The sun takes ~4 hours to go from a bit above the horizon in the east coast to a bit below the horizon on the west coast (solar panels make some power in twilight).
Wind also helps since wind makes more power at night, as does demand which is dramatically lower at night.
For coal, Great. Making coal economical is excellent. We should have banned it worldwide 20 years ago.
USA should explore Pumped Storage Hydropower more, it has same or better efficiency than battery storage and can use existing facilities like hydroelectric dams
Part of the pumped storage problem is "where can you do it?"
There's a good number of 'em: https://en.wikipedia.org/wiki/Category:Pumped-storage_hydroe...
https://www.ferc.gov/media/licensed-pumped-storage-projects-...
You'll see that most of them are in the Appalachian mountains and in the Sierra mountain range.
The one in Missouri is one of the interesting ones that isn't in either.
https://en.wikipedia.org/wiki/Taum_Sauk_Hydroelectric_Power_...
> The Taum Sauk pumped storage plant is a power station in the St. Francois mountain region of Missouri, United States about 90 miles (140 km) south of St. Louis near Lesterville, Missouri, in Reynolds County.
It has a hydraulic head of 860 feet and that represents the challenge - you need to find places in the US where you can get several hundred feet of elevation in a short distance.
Hypothetically, lets build one in Minnesota... Taum Sauk Mountain is the highest point in Missouri. The highest point in Minnesota is Eagle Mountain (in the boundary waters - you can't build there, pretend we can) ... the elevation to the top os 550 feet (about half what Taum Sauk provides) over 3.5 miles (Taum Sauk is just over 1 mile). ( https://maps.app.goo.gl/vHfWarwubaLvsf5z7 )
Much of the US is too flat for it to be useful.
Solar+A couple of hours of batteries is already economically viable. The storage problem that is still expensive is bridging days/weeks of insufficient sun and wind.
> The storage problem that is still expensive is bridging days/weeks of insufficient sun and wind.
It might help if the US wasn't so anti off-shore wind at the moment.
The US uses around 4TWh of electricity a night. A battery with that capacity, to get through the night with no generation, would cost over a trillion dollars. Of course thered still be some generation at night, but still, using a battery just to get through the night is not even close to viable
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Coal is a dead end anyway.