Small-scale hydropower development potential has been mapped out in 14 West African Countries in a project undertaken by Pöyry, working in conjunction with the Economic Community of West African States (ECOWAS), and the ECOWAS Centre for Renewable Energy and Energy Efficiency (ECREEE).

Pöyry announced it has mapped the small scale hydropower potential in the ECOWAS countries using the latest geographic information system (GIS) technology. The groundbreaking data, which maps the hydrological conditions, the hydropower potential as well as climate change information for more than 500,000 river reaches, will be utilised by stakeholders in each country to identify and implement vital hydropower projects, as the region seeks to develop reliable and sustainable long-term solutions to the energy challenge.

Up until recently the potential for small scale hydropower in West Africa has neither been known in detail nor been exploited – only some 50 hydropower plants are operational in the region. A strategic development of the hydropower resources in most ECOWAS countries has been constrained by economic conditions but also by the lack of information on river flow, river topography and hydropower potential, especially in the headwater regions of the West African river systems. Also uncertainty with respect to the possible impact of climate change on water availability and hydropower production is considered a risk by potential hydropower investors. The ECREEE hydropower maps developed by Pöyry significantly improve the data base for small hydropower development in the region and also provide valuable information for medium and large projects.

"The excellent cooperation between ECREEE and Pöyry resulted in a valuable product that is accessible to all stakeholders in the hydropower development process,” commented Martin Fuchs, Section Head Hydro Consulting, Pöyry. “It is an important source of information for hydropower master planning at the national level and will support potential investors in decision-making, investment planning and risk management. We are proud of our work with ECREEE and hope to replicate the success of this project in other regions of Africa, Asia and South America."

The key findings of the study are:

  • Nigeria identified as having the highest theoretical hydropower potential of all 14 ECOWAS countries studied.
  • Guinea, Sierra Leone and Liberia show a high potential for small hydropower whilst Mali and Niger are unsuitable for small projects.
  • The climate change projections show that in most parts of West Africa no significant change is projected in future mean annual discharge, but there are regional variations in the projections. Evaporation is projected to increase, but also annual rainfall is projected to increase, especially in the Fouta Djallon Highlands in Guinea, which is the headwater region for rivers of regional importance including the Niger, Senegal and Gambia rivers.

The key research areas were:

  • Hydropower Resource Mapping: Pöyry created river network and sub-catchment GIS layers with relevant attributes showing mean monthly river flows, river topography and the resulting hydropower potential. This provides a regional overview and enables identification of sub-catchments and rivers with attractive hydrological and physiographic conditions for hydropower development. The information serves as a basis for follow-up studies and targeted discharge measurement campaigns.
  • Existing Hydropower Plants: Pöyry prepared an up-to-date GIS layer that shows the location and metadata of all existing hydropower plants in West Africa. This information is required to identify those river reaches where the hydropower potential is already utilised.
  • Climate Change Information: For each river reach also flow conditions and hydropower potential under conditions of climate change have been assessed. For the assessment the regional climate change projections based on the Coordinated Downscaling Experiment (CORDEX) have been used. CORDEX is sponsored by the World Climate Research Program and considered the most up to date climate change information currently available for this part of Africa.