In August, the Intergovernmental Panel on Climate Change (IPCC) published their most incriminating report yet on the state of the global climate crisis. This means that now, more than ever, we need to be investing in renewables like hydropower, right?
Not necessarily.
Hydropower is often presented as a climate solution, and its low-carbon electricity is used to justify adverse impacts on community and environment. Though the framing of remote communities as sacrifice zones for the sake of so-called “green energy” is disturbing enough, the climate benefits of this sacrifice have been over-exaggerated.
Between deforestation, the production of cement and steel used for construction, the submergence and decomposition of organic matter like trees, bushes, and plants, and the subsequent release of methane from the reservoir’s surface, it’s clear that all hydropower comes with a carbon footprint.
In warm climates like India, reservoirs produce substantial amounts of methane. Ravi, a member of India’s Water Conflicts Forum, shared that these emissions can be as high as those of thermal sources like coal and gas.
According to Gary Wockner, an environmental author, advocate, and consultant, this isn’t a localized problem. Hydropower emissions can also be high in the temperate and boreal regions of North America, though they often go unreported.
One of the biggest problems in understanding these emissions is that the carbon footprint of hydroelectric reservoirs are not reported under IPCC guidelines. This is problematic, given that they total an estimated billion tonnes of greenhouse gases each year, or about 1.3% of anthropogenic CO2-equivalent emissions (source).
Emissions are also significantly underreported by hydroelectric developers, if they are reported at all. For example, BC Hydro, a Canadian crown corporation, justified the development of their controversial Site C Project by touting emissions of 10.5 gCO2e/kWh (source). Gary Wockner and his team from Colorado State University conducted an independent review of the project, and found its projected emissions to be closer to 396 gCO2e/kWh (source), similar to those of natural gas. When asked to comment on this discrepancy, or even explain how they calculated their figures, BC Hydro refused.
This lack of transparency may have dangerous implications for the future of our energy. Julian Felvinci of the North American Megadam Resistance Alliance emphasized the risk of pushing hydropower as a false climate solution:
“It’s almost just taking one really bad idea such as fossil fuels, and replacing it with another really bad idea. And we don’t have time for that. We don’t have time for increased methane emissions and carbon dioxide emissions and loss of forests for carbon sequestration and ecosystems when we’re experiencing rapid climate change and mass extinctions.”
The IPCC report is a reminder to rethink our future and evaluate our options. Sustainable power could mean conservation, efficiency, retrofitting old dams, investing in renewable energies, or even developing new hydropower with an honest assessment of its impacts, including the incorporation of reservoir emissions into IPCC carbon accounting. It does not mean pushing environmentally and socially damaging projects with unsubstantiated promises of low-carbon hydroelectricity.
Scherer and Pfister’s 2016 life cycle assessment of hydroelectric facilities revealed many of their emissions to be higher than previously thought. Compared to dirty sources like coal and natural gas, whose average emissions were taken from a 2014 IPCC report, we fail to see the promised climate benefits. Photo Credits: Kariba Dam – Marcus Wishart, World Bank Group, Nam Pung Dam – Amazing Thailand, Robert-Bourassa Dam – Hydro-Quebec, Hoover Dam – United States Bureau of Reclamation. Hoover Dam: https://www.usbr.gov/lc/hooverdam/
Kariba Dam: https://www.worldbank.org/en/region/afr/brief/the-kariba-dam-rehabilitation-project-fact-sheet
La Grande/Robert-Bourassa: http://www.hydroquebec.com/visit/baie-james/bourassa.html
Nam Pung Dam: https://www.tourismthailand.org/Attraction/nam-pung-dam
Emissions from each dam: Scherer L, Pfister S (2016) Hydropower’s Biogenic Carbon Footprint. PLOS ONE 11(9)
Written by Andrea Sutherland for Dam Watch International.
Cover photo caption: The above emission rates are from life cycle assessments provided by BC Hydro to justify the construction of Site C. The lower figure for Site C is from a report paid by and prepared for BC Hydro. The higher one is from Wockner’s independent study. The others were taken from a 2014 IPCC report. Photo Credit: Garth Lenz, The Narwhal.
