Net lifecycle greenhouse gas emissions from hydroelectric development on the lower Nelson River: implications for energy policy
Year: 2026
Type: article
Abstract: Creating reservoirs through flooding land for the purpose of hydroelectric power generation may impact carbon cycling and alter greenhouse gas (GHG) emissions. To examine the impacts of flooding in northern peatland environments for hydroelectric production, the pre-impoundment and post-impoundment net 100-year lifecycle GHG emissions were modelled for the recently created Keeyask hydroelectric reservoir located on the Nelson River in northern Manitoba, Canada. Net 100-year lifecycle GHG emissions were also modelled for all hydroelectric reservoirs on the lower Nelson River, including the Churchill River Diversion (CRD) and possible future hydroelectric development. The UNESCO/IHA GHG Reservoir (G-res) Tool, version 3.31 was selected to model lifecycle GHG emissions from both the Keeyask and lower Nelson River reservoirs. Annual Net Keeyask reservoir GHG emissions are modelled to be 86 gCO2e/m2/yr (95% Confidence Interval 75 – 98). Total Net GHG emissions for the 100-year life of the Keeyask reservoir are estimated to be 861,990 tonnes CO2e (95% CI 749,988 – 987,936). The modelled reservoir GHG 100-year average lifecycle emission intensity is estimated to be 2.2 gCO2e/kWh. Total Net GHG emissions for the hydroelectric reservoirs located on the lower Nelson River, including the CRD, Keeyask, Kettle, Long Spruce, and Limestone reservoirs are modelled to be 24,339,968 t CO2e (95% CI 21,349,582 - 27,729,138) over the 100-year lifecycle of the reservoirs. Approximately 95% of the Net emissions are modelled to occur from the CRD (80%) and the Kettle reservoir (15%). From 2025 to 2075, the remaining lifecycle GHG emission intensity for the lower Nelson River reservoirs, including the CRD, is modelled to be 7.9 g CO2e/kWh, similar to median values (that range from 8 to 52 g CO2e/kWh) for electricity generated from ocean waves, nuclear, wind, solar, and biomass technologies. The largest source of modelling uncertainty lies with the CO2 and CH4 emission factors selected for the pre-flood reservoir footprint, and with how well the G-res Tool was calibrated for northern, peatland reservoirs. Modelled lifecycle reservoir GHG emissions and emission intensity associated with the lower Nelson River are low and declining. Electricity generated from lower Nelson River hydropower can help Manitoba and Canada achieve net-zero GHG emission goals.
Source: Mspace (University of Manitoba)
Author: Gill, Robert E.
Language: English
Subfield: Ecology
Field: Environmental Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213477431