Hydroelectric dams have environmental challenges
Hydro dams aren’t always low carbon and there are other problems as well
For many, hydroelectric dams seem as if they should be environmentally benign, delivering large quantities of carbon-free electricity. The water is renewable, there are no fossil fuels involved and you end up with lovely lakes.
But dams have a dark side and siting is important.
Tropical dams, especially in rainforest areas such as the Amazon, are heavy emitters of GHGs, reaching parity only around the 60-year mark. This is due to anaerobic decomposition of the trees, underbrush and soil biomass that are submerged. That anaerobic decomposition emits not only carbon dioxide, but methane, which is a much more intense greenhouse gas. More northern dams typically have much lower lifecycle carbon emissions as they are in areas with much less biomass. This means that dams such as Quebec’s James Bay dam, the Manitoba Keeyask project and Norway’s dams — which it wants to retrofit with new generators suitable for making it a battery for…
