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A interesting comparison is the first dam they are taking down produces about 112 million kwh of energy a year. Which is about the same as 50MW worth of solar.

A interesting comparison is the first dam they are taking down produces about 112 million kwh of energy a year. Which is about the same as 50MW worth of solar. One gets the feeling these dam's wouldn't be worth building today.

poulsbohemian 3y ago
You are probably right, but maybe not quite for the reasons you imagine... many of the dams in the northwest run at only a tiny percentage of their possible output because increasing their productivity could have poor outcomes for fish, etc. So they have already ratcheted back much of their output as a compromise. But - we also have a lot of anti-solar, anti-wind people who try to block those projects for reasons I would call unscientific and emotional. So you can't outright replace the dams just yet either. The dams are also really good at providing a base load, as even when the wind doesn't blow that water just keeps moving.
- teachrdan 3y ago
  With increasing drought and general weather variability, I wonder if they are still reliably provide a base load. For an extreme case, see Lake Powell drying up so much last year it generated little power: https://www.cnn.com/2022/04/30/us/west-drought-lake-powell-hydropower-or-water-climate/index.html https://www.cnn.com/2022/04/30/us/west-drought-lake-powell-h...
Arrath 3y ago
Yeah, these dams are rather small in the absolute scale. Compared to one of the big guys like Grand Coulee with its production of 21 billion kwh/year, they're peanuts.
jeffbee 3y ago
They aren't worth keeping, either. The PG&E Feather River project for example can be replaced by a cheap mid-sized PV farm. Those run-of-the-river hydroelectric projects are way too dangerous to keep around which I think is best exemplified by the fact that the Feather River project started the largest wildfire in California history. So on the one hand you have the almost negligible benefit of an unreliable, seasonal power source and on the other hand you have the extirpation of salmon and a million acres of burnt forests. I known which one I prefer.
rootusrootus 3y ago
Yeah, these made sense in 1925, when we produced just a fraction of what we produce today. But at this point maybe we should just start tearing out the ones that aren't providing any other valuable service and budget for solar & wind to replace their output.
- Gibbon1 3y ago
  I think so. How little power some of these old dams produce is a bit shocking by modern standards. I remember the allies during WWII went to a bunch of trouble to knock out a some dams on the Ruhr. I think one of them produced 5MW of power. So these dams produce a round error amount of energy[1]. But the effect on the watershed is not a rounding error. And a lot of them are old which brings costs due to maintenance and engineering analysis. And that applies to the 60 year old power lines to tie these to the grid. [1] Compare with fish. Friends mom lived in Idaho which is popular with fishermen. Some state analysis showed fish tourism generates about $1000 per fish caught.
keyboard_slap 3y ago
That's a poor comparison. We can't control when we get solar power, and we can't easily store excess solar power right now. Hydropower is available on demand. Green sources of electricity like this are worth building today, because the current best alternative appears to be natural gas turbine generation.

poulsbohemian 3y ago

You are probably right, but maybe not quite for the reasons you imagine... many of the dams in the northwest run at only a tiny percentage of their possible output because increasing their productivity could have poor outcomes for fish, etc. So they have already ratcheted back much of their output as a compromise. But - we also have a lot of anti-solar, anti-wind people who try to block those projects for reasons I would call unscientific and emotional. So you can't outright replace the dams just yet either. The dams are also really good at providing a base load, as even when the wind doesn't blow that water just keeps moving.

teachrdan 3y ago
With increasing drought and general weather variability, I wonder if they are still reliably provide a base load. For an extreme case, see Lake Powell drying up so much last year it generated little power: https://www.cnn.com/2022/04/30/us/west-drought-lake-powell-hydropower-or-water-climate/index.html https://www.cnn.com/2022/04/30/us/west-drought-lake-powell-h...

Arrath 3y ago

Yeah, these dams are rather small in the absolute scale. Compared to one of the big guys like Grand Coulee with its production of 21 billion kwh/year, they're peanuts.

jeffbee 3y ago

They aren't worth keeping, either. The PG&E Feather River project for example can be replaced by a cheap mid-sized PV farm. Those run-of-the-river hydroelectric projects are way too dangerous to keep around which I think is best exemplified by the fact that the Feather River project started the largest wildfire in California history. So on the one hand you have the almost negligible benefit of an unreliable, seasonal power source and on the other hand you have the extirpation of salmon and a million acres of burnt forests. I known which one I prefer.

rootusrootus 3y ago

Yeah, these made sense in 1925, when we produced just a fraction of what we produce today. But at this point maybe we should just start tearing out the ones that aren't providing any other valuable service and budget for solar & wind to replace their output.

Gibbon1 3y ago
I think so. How little power some of these old dams produce is a bit shocking by modern standards. I remember the allies during WWII went to a bunch of trouble to knock out a some dams on the Ruhr. I think one of them produced 5MW of power. So these dams produce a round error amount of energy[1]. But the effect on the watershed is not a rounding error. And a lot of them are old which brings costs due to maintenance and engineering analysis. And that applies to the 60 year old power lines to tie these to the grid. [1] Compare with fish. Friends mom lived in Idaho which is popular with fishermen. Some state analysis showed fish tourism generates about $1000 per fish caught.

keyboard_slap 3y ago

That's a poor comparison. We can't control when we get solar power, and we can't easily store excess solar power right now. Hydropower is available on demand. Green sources of electricity like this are worth building today, because the current best alternative appears to be natural gas turbine generation.