The Net Impact of Hydroelectric Reservoir Creation on Greenhouse Gas Emissions: A Study of the Eastmain-1 Reservoir in the Eastern James Bay region of Quebec, Canada

Strachan, I B,  Lemieux, M , Bonneville, M, Roulet, N,  and Tremblay, A

In order to satisfy present and future energy demands and to minimize greenhouse gas (GHG) emissions, there is a growing need to develop energy sources that are not based on combustion. In the boreal regions of Canada, there is a huge potential for hydroelectricity production. However, in most cases, large areas of the boreal ecosystem must be inundated to create hydroelectric reservoirs. Previous studies have established that reservoirs emit GHGs, but these studies have typically focused on emissions some years after reservoir creation. The critical question that has not been asked is 'what is the net change in the exchange of GHG that results directly from the creation of the reservoir?' - i.e. 'what is the net difference between the landscape scale exchange of GHGs before and after reservoir creation, and how does that net difference change over time from when the reservoir was first created to when it reaches a steady-state condition?'. The Eastmain-1 (EM-1) hydroelectric reservoir, located in the James Bay region of Quebec was created in late 2005 and provides a tremendous opportunity to study the impacts of reservoir creation on GHG emissions which are still largely unknown for this type of land conversion. The creation of the EM-1 hydroelectric reservoir required the flooding of over 600 km2 of the boreal ecosystem along the Eastmain River, of which 65% was occupied by forest, 14% by peatland, and 21% by lakes and rivers. In order to assess the impacts of the creation of the reservoir on GHG emissions, three eddy covariance (EC) tower flux sites were established in a black spruce forest, peatland and on an island in the reservoir itself to measure continuous net ecosystem exchange (NEE) of CO₂. Together, these represent the dominant terrestrial pre-flooded (forest and peatland) and post-flooded (reservoir) environments. The forest and reservoir EC systems were installed and operational by the end of summer 2006 with the peatland site coming on-line summer of 2008. Through the use of the forest and peatland analogue sites, the EC results will be used to evaluate the pre-flooded vs. post- flooded CO₂ fluxes, and thus the net impact of the EM-1 reservoir creation in terms of CO₂ emissions. By measurement and modeling, we will provide an estimate of the change in GHG source the atmosphere would see, an estimate of the net emissions that can be used for intercomparison of GHG contributions with other modes of power production and a basis on which to develop biogeochemically sound, verifiable, and transparent estimates for GHG accounting. This presentation will provide an overview of the project and its goals and will discuss preliminary results from the EC and terrestrial measurement campaigns.

Cliquer ici pour visualiser le poster

Retour à l'index des résumés