Sustainable hydroelectric development in Gabon

Workshop – 07.02.2019

On January 30, PSR participated in the Workshop on Planning at the scale of hydrographic basin and sustainable hydroelectricity, organized by The Nature Conservancy (TNC) in Gabon. The workshop presented the results of a PSR study for TNC on the hydroelectric development of the Estuaire electrical system (the most important in the country, which includes the capital Libreville) through the hydrographic basins of the Mbé, Komo and Abanga rivers.

Gabon is a country on the west coast of Central Africa with a small population (2 million inhabitants) and a great diversity of ecosystems, mostly well conserved. Some projects are close to national parks, home to elephants (photo), lions, gorillas and many species of fish. Hence the concern that hydroelectric development, which is quite important for the economic development of the country, does not cause significant impacts on the environment.

Fonte: Our World, Our Story 2017 Annual Report, The Nature Conservancy

In this study, the HERA computational environment developed by PSR was used to study scenarios of hydroelectric development considering economic aspects (budgets were generated for various alternatives) and environmental aspects, especially the implications of the ecological flows downstream of the Ngoulmendjim project on its installed capacity and other parameters of this project, which is in a more advanced state. The concern is justified by the possible environmental impacts, especially for aquatic species downstream of the project (due to the significant reduction of flows) in the Komo River and on the small tributary Petit Tsibilé in the receiving basin, which will have an opposite impact (a substantial increase of the flows). Various alternatives for the hydro plant cascade arrangement were generated for stakeholder assessment (General Directorate of Energy, General Directorate of Water, General Directorate for Environment and Parks) considering scenarios of environmental flows in the Komo and energy sales prices of the PPA. The economic benefit of these alternatives, the annual energy produced, as well as metrics on environmental impact (flooded area in intact forest landscapes, emissions of greenhouse gases, aquatic ecosystems impacted by the change of flows and contribution of sediments, etc.) They could be discussed through a web visualization platform (see graphic).

The workshop had two developments: on the side of government agencies there is interest in more training for the use of decision support tools, among which HERA. For TNC there is a manifestation of interest in extending the Estuaire study to five other Gabon hydrographic basins with hydroelectric potential.