Reservoirs in Alabama are sources of greenhouse gas emissions

Team Reservoir Emissions

Published 6/10/2022

Purpose

Hydropower is touted as a source of clean energy but there is increasing attention being drawn to emissions not traditionally included in these calculations, such as those coming from the reservoir itself. Alabama Rivers Alliance recognized these sources of greenhouse gas as important considerations when determining the future of hydropower dams. We partnered with ARA to estimate greenhouse gas emissions from two reservoirs as part of their FERC relicensing using the g-res tool.

Method

G-res, a publicly available tool that estimates greenhouse gas emissions from reservoirs, was used to estimate emissions from two reservoirs in Alabama (Harris and Weiss). We gathered publicly available information on the two reservoirs as required of g-res, including land use, dam building materials, reservoir services, and general reservoir attributes. This information was then entered into the g-res tool, which provided an estimate of greenhouse gas emissions for each reservoir.

Results

We found that both reservoirs had emissions above the limits proposed for ‘clean energy’, which have not yet been included in legislation but are under consideration. The EPA is currently in the midst of a four-year study to determine if hydropower should truly be considered zero-emissions, as it now does. Results of emissions at Weiss Reservoir place it on par with emissions from fossil fuel energy, thereby not qualifying it as clean energy. Harris Reservoir’s GHG emissions are lower than those at Weiss, but still well above the proposed clean energy threshold.

Broader Impact

This study helped to bring community attention to an issue that experts have recognized for some time. ARA used our report as part of their comments to FERC to argue against relicensing these two dams and they have also worked to spread the word about both our findings and the utility of the g-res tool. Interest in the g-res tool from other advocacy groups has spawned a project with the communications team to create a tutorial video on how they can use g-res to estimate emissions from other reservoirs.