Impoundment of hydroelectric reservoirs induces decomposition of a small fraction of the flooded biomass (forests, peatlands and other soil types) and an increase in the aquatic wildlife and vegetation in the reservoir.

The result is higher greenhouse gas (GHG) emissions after impoundment, mainly CO2 (carbon dioxide) and a small amount of CH4 (methane).

However, these emissions are temporary and peak two to four years after the reservoir is filled.

During the ensuing decade, CO2 emissions gradually diminish and return to the levels given off by neighboring lakes and rivers.

Hydropower generation, on average, emits 50 times less GHGs than a natural gas generating station and about 70 times less than a coal-fired generating station.

Many years ago, Hydro-Québec decided to make use of the province's water resources to meet the demand for electricity. This policy has contributed greatly to Québec's excellent record on greenhouse gas emissions.

In partnership with universities, research centres and other electric utilities, Hydro-Québec has conducted research on greenhouse gases since 1993.

The objectives of these studies are to:

  • Improve understanding of the impacts of our reservoirs on GHG emissions.
  • Learn about the processes that cause GHG emissions.
  • Monitor changes in GHG emissions in new projects.
  • Compare GHG emissions from hydropower with those from other energy sources.
  • Obtain potential CO2 emissions credits in the future Canadian carbon market.
CO2 flux samples

Specialized documentation

Technical and scientific reports

  • Demarty, M., D. Marchand and A. Tremblay. 2012. Centrales de l'Eastmain-1A et de la Sarcelle et dérivation Rupert – Étude des flux de gaz à effet de serre – Résultats été 2012. (Eastmain-1-A and Sarcelle powerhouses and Rupert diversion – Study of greenhouse gas fluxes – Summer 2012 results). Joint report by Environnement Illimité Inc. and Hydro-Québec Production, Direction – Gestion des actifs et conformité réglementaire. 38 p and app.
  • Marchand, D., M. Demarty, and A. Tremblay. 2012. Aménagement hydroélectrique de l'Eastmain-1 – Étude des flux de gaz à effet de serre – Résultats été 2012. (Eastmain-1 Hydroelectric Development – Study of greenhouse gas fluxes – Summer 2012 results). Joint report by Environnement Illimité Inc. and Hydro-Québec Production, Direction – Gestion des actifs et conformité réglementaire. 46 p and app.
  • Marchand, D., M. Demarty and A. Tremblay. 2012. Systèmes automatisés de mesure des gaz à effet de serre – Eastmain-1, Robert-Bourassa et Rivière-des-Prairies – Résultats 2011-2012. (Automated greenhouse gas measuring systems – Eastmain-1, Robert-Bourassa and Rivière-des-Prairies – 2011–2012 Results). Joint report by Environnement Illimité Inc. and Hydro-Québec Production, Direction – Gestion des actifs et conformité réglementaire. 39 p
  • Bastien, J., M. Demarty and A. Tremblay. 2010. Étude des flux de gaz à effet de serre des milieux aquatiques de la Côte-Nord et de la Mauricie – Résultats été 2010. (Study of the greenhouse gas fluxes of aquatic environments in the Côte-Nord and Mauricie regions – Summer 2010 results). Joint report by Environnement Illimité Inc. and Hydro-Québec Production, Direction – Barrages et environnement. 54 p and app.

Monograph

  • Tremblay, A., L. Varfalvy, C. Roehm and M. Garneau. 2005. "Greenhouse Gas Emissions: Fluxes and Processes, Hydroelectric Reservoirs and Natural Environments (Émissions de gaz à effet de serre : Flux et processus, réservoirs hydroélectriques et milieux naturels)". Environmental Science, New York, Springer. 732 p. Abstract [PDF] (in French only)

This monograph is available for consultation at Hydro-Québec's environment and communities documentation centre.

It can also be purchased from www.amazon.ca or directly from the publisher.

Scientific articles

  • Teodoru, C. R., J. Bastien, M.-C. Bonneville, P. del Giorgio, M. Demarty, M. Garneau, J.-F. Hélie, L. Pelletier, Y. T. Prairie, N. Roulet, I. Strachan and A. Tremblay. 2012. "The Net Carbon Footprint of a Newly Created Boreal Hydroelectric Reservoir." Global Geochemical Cycles, Vol. 26, GB2016, DOI:10.1029/2011GB004187.
  • Bastien, J., M. Demarty and A. Tremblay. 2011. "CO2 and CH4 Diffusive and Degassing Emissions from 2003 to 2009 at Eastmain 1 Hydroelectric Reservoir, Québec, Canada." Inland Waters (1), p 113-123. DOI:10.5268/IW-1.2.349.
  • Demarty, M., J. Bastien and A. Tremblay. 2011. "Annual Follow-up of Gross Diffusive Carbon Dioxide and Methane Emissions from a Boreal Reservoir and Two Nearby Lakes in Québec, Canada." Biogeosciences, vol. 8, p 41-53.
  • Demarty, M., J. Bastien, A. Tremblay, R. Hesslein and R. Gill. 2009. "Greenhouse Gas Emissions from Boreal Reservoirs in Manitoba and Québec, Canada, Measured with Automated Systems." Environmental Science and Technology, vol. 43, no 23, p 8905-8915.
  • Prairie, Y. T., P. A. del Giorgio, C. L. Roehm and A. Tremblay. 2009. "Insights on Riverine Metabolism from Continuous Measurements of CDOM Fluorescence In Eastmain-1 Reservoir, Quebec." Verh. Internat. Verein. Limnol. Vol. 30, Part 10, p 1545-1548.
  • Tranvik, L. J., J. A. Downing, J. B. Cotner, S. A. Loiselle, R. G. Striegl, T. J. Ballatore, P. Dillon, K. Finlay, K. Fortino, L. B. Knoll, P. L. Kortelainen, T. Kutser, S. Larsen, I. Laurion, D. M. Leech, S. L. McCallister, D. M. McKnight, J. M. Melack, E. Overholt, J. A. Porter, Y. Prairie, W. H. Renwick, F. Roland, B. S. Sherman, D. W. Schindler, S. Sobek, A. Tremblay, M. J. Vanni, E. von Wachenfeldt, E. D. Wachenfeldt and G. A. Weyhenmeyer. 2009. "Lakes and Reservoirs as Regulators of Carbon Cycling and Climate." Limnology and Oceanography, vol. 54 (6 part 2), p 2298-2314.

See also