4 ms·

Yes, this is exactly what a dam is (pumping or releasing, or using rain). Hydo is very cool, and very green. Some things to remember, however: - need to drow

by steeve 7y ago

Yes, this is exactly what a dam is (pumping or releasing, or using rain). Hydo is very cool, and very green. Some things to remember, however: - need to drown whole valleys (very high impact on local wildlife) - energy density is not that good (i don't have the numbers but the volumes of water moved are huge, hence dams) - very rapid piloting and low maintenance, so nice to absorb spikes

ch4s3 7y ago
> Hydo is very cool, and very green. Well, maybe. I think this depends on what you mean by "green". If you mean low on CO2 emissions, then sure, but we need to consider habitat loss, methane emissions from decomposition, and the possibility of triggering earthquakes. Hydro is also quite expensive to build, and often requires seizing land through processes like Eminent Domain (in the US).
- steeve 7y ago
  You are right, I was meaning green in the sense of gCO2eq/kWh.
bmelton 7y ago
Hydro may require drowning valleys, but micro-hydro with a weir utilizes existing waterways with minimal impact. As to energy density, there's no fixing that, but for most people, density is far less a concern than 'enough' -- solar isn't a viable solution for my current household because it would require clearing enough trees that it feels counterproductive. So, I can go with solar, but I couldn't be self-sustaining on solar. For most people, that's not a real concern. If you can capture enough solar power during the day to offset your energy bill to zero or near zero, that's good enough, but my concerns are a little more esoteric. That said, for either method, density hasn't really played a factor beyond local storage into battery banks - which is normal enough, but a very different concern.
hinkley 7y ago
I've heard it argued that depending on the kind and quantity of vegetation in the valley being flooded, the net methane release from so much rotting plant matter may upend the whole carbon balance of the project. That is not to say that all dams do this, but that consideration is necessary and may require modifying or rejecting certain proposals.

by steeve 7y ago

ch4s3 7y ago

> Hydo is very cool, and very green. Well, maybe. I think this depends on what you mean by "green". If you mean low on CO2 emissions, then sure, but we need to consider habitat loss, methane emissions from decomposition, and the possibility of triggering earthquakes. Hydro is also quite expensive to build, and often requires seizing land through processes like Eminent Domain (in the US).

steeve 7y ago
You are right, I was meaning green in the sense of gCO2eq/kWh.

bmelton 7y ago

Hydro may require drowning valleys, but micro-hydro with a weir utilizes existing waterways with minimal impact. As to energy density, there's no fixing that, but for most people, density is far less a concern than 'enough' -- solar isn't a viable solution for my current household because it would require clearing enough trees that it feels counterproductive. So, I can go with solar, but I couldn't be self-sustaining on solar. For most people, that's not a real concern. If you can capture enough solar power during the day to offset your energy bill to zero or near zero, that's good enough, but my concerns are a little more esoteric. That said, for either method, density hasn't really played a factor beyond local storage into battery banks - which is normal enough, but a very different concern.

hinkley 7y ago

I've heard it argued that depending on the kind and quantity of vegetation in the valley being flooded, the net methane release from so much rotting plant matter may upend the whole carbon balance of the project. That is not to say that all dams do this, but that consideration is necessary and may require modifying or rejecting certain proposals.