Estimation of the Anthropogenic Component of Greenhouse Gas Fluxes from the Surface of Energy Reservoirs in the Russian Federation

Anthropogenic emissions and sinks of greenhouse gases from hydropower reservoirs in the Russian Federation are estimated based on the results of field measurements in 2021–2023. Methane fluxes from the surface of reservoirs are measured by researchers of the Institute of Atmospheric Physics, Russian Academy of Sciences, in the shallow and deepwater parts of the basins of nine (Kolyma, Bureya, Volgograd, Boguchan, Zeya, Kuibyshev, Rybinsk, Chirkey, and Sayan–Shushin) reservoirs. Based on these measurements and modeling data, the results are analyzed and compared with the methane emission factors presented in the methodological documents of the Intergovernmental Panel on Climate Change (IPCC). Adjusted coefficients using calculations of complexity tiers 1 and 2 according to the IPCC are developed. Based on the results, it is shown that the revised national factors are on average 63% lower than the default IPCC factors. A methodology for estimating the anthropogenic component of the greenhouse gas buget during reservoir construction at using Tier 3 approach is developed based on carbon budget calculations and the difference between parameters of the reservoir water and the river located upstream. Using the example of the Rybinsk Reservoir, the anthropogenic component of the greenhouse gas flux corresponding to a net sink of 0.18 kg CO2-eq/m2/year is estimated. A conclusion about the possibility of a negative carbon footprint of electricity from large hydroelectric power plants is drawn.