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Originally Posted by CanSpice
Except for the construction of the dam and reservoir, of course. But then again, if you take construction into account solar isn't all that green either. Hydro's operation is non-polluting (except they've found that reservoirs emit more methane than we previously thought) so I guess in that sense it's green, but all that cement needs to be made, construction vehicles need to operate during its construction, etc, etc, etc. And the impact to the surrounding environment caused by flooding a valley isn't nothing too.
But as you say, of all the options it's the least shitty one. But let's not pretend that hydro is "green" and doesn't have any impact. Renewable is a much better term. |
Generally, higher emitting reservoirs are in the tropics. In BC, not so much, especially if the topsoil is stripped out.
Glaciers scraped so much of the soils away that whole lot else is left to generate methane or CO2. Generally, there is so much less decaying plant matter in temperate areas that experts generally put hydro plants at about 4g CO2e / kWh.
Wind power and solar are both in the 20-60g CO2e / kWh range, from the manufacturing of the equipment and the generally shorter lifespan. Silicon, steel and concrete are all needed in huge quantities for turbines and wind plants.
Geothermal also generates some CO2 from releasing trapped gas. The earthquake side effect is also pretty cool
For reference, coal emits several hundred grams per kWh generated.
Site C is also an earthen fill dam, which is basically a succession of sorted soil sizes. Earth fill is way less energy intensive to construct than concrete.
Lastly, concrete has been shown to reabsorb most of the CO2 originally emitted during it's lifespan. It's not nearly as bad as people first presumed. Carbonates form in fractures, which sequesters the CO2.
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