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[NAIROBI] Large dams planned for completion by 2030 in Eastern and Southern Africa could increase the risk of electricity supply disruptions because they will be concentrated in areas with similar rainfall patterns and likewise vulnerable to droughts, says a study.
The study published in the Nature Energy journal last month (8 December) shows that hydropower covers a significant and rapidly expanding amount of electricity production in the two sub-regions.
“By 2030, 70 per cent and 59 per cent of total hydropower capacity will be located in one cluster of rainfall variability in Eastern and Southern Africa, respectively,” the researchers note.
Declan Conway, the study’s lead author and professorial research fellow at the UK-based Grantham Research Institute, London School of Economics, says that hydropower contributes to 90 per cent of national electricity generation in Ethiopia, Malawi, Mozambique, Namibia and Zambia, citing several new developments commissioned over the last decade, including the Grand Ethiopian Renaissance Dam on the Blue Nile.
Credit: Nature Energy
He adds, “We focused on hydropower because it is such a major component of electricity-generating capacity in many countries of Sub-Saharan Africa and because we knew anecdotally of several droughts that had disrupted electricity supply with major social and economic consequences.”
The researchers used rainfall data based on measurements with rain gauges and supplemented the findings with satellite estimates.
“We used a statistical technique called cluster analysis to group areas with similar rainfall variability for the period 1956 to 2011,” explains Conway. “We found three different rainfall patterns (clusters) in Eastern Africa and seven in Southern Africa.”
The researchers mapped the location of current and planned dams, and identified 27 dams in eastern Africa, projected to more than double to 57, and currently 16 in Southern Africa, projected to increase to 29 by 2030.
They found that rainfall patterns in eastern and southern Africa are likely to become more variable as a result of climate change. "River flows and water stored in reservoirs drive hydro generation and are highly sensitive to fluctuations in rainfall so climate change is likely to exacerbate hydropower supply problems,” says Conway.
Sub-Saharan Africa, according to Conway, has seen renewed interest in dams for hydro-power after a hiatus in the 1980s and 1990s: “Many countries have been able to self-finance projects”, he says, citing funding and expertise from China as an additional factor.
But the knock-on effects of electricity disruption are wide-ranging and could have implications for services, businesses and economic activity throughout the society.
Whereas regional power sharing mechanisms known as ‘Power Pools’ could provide a means to buffer variations in river discharge or reservoir storage through electricity trading, energy trade is limited in the two regions, the study adds.
There are significant infrastructural and political challenges to these power-sharing systems. Underinvestment, failures of state monopolies leading to inefficiency, low technological dynamism and poor service provision are features of electricity utilities in many African countries.
“Guidelines to incorporate climate risks into infrastructure planning are now emerging. [When planning for dams], decision-makers should consider the location of dams and rainfall patterns, and how changes in rainfall could affect hydropower supply,” he tells SciDev.Net.
“We focused on hydropower because it is such a major component of electricity-generating capacity in many countries of Sub-Saharan Africa.”
Declan Conway, London School of Economics
Elikana Kalumanga, natural resource management expert at the Institute of Resource Assessment at Tanzania’s University of Dar-es-Salaam, says most hydropower plants in Eastern and Southern Africa are largely rain-fed and thus mainly depend on existence of forested mountains.
“Multi-stakeholder engagement and collaborative processes are necessary to safeguard the water catchment areas and sustain water flows required to produce electricity from various hydroelectric power plants.”
Kalumanga calls for a need to assess how planned hydroelectric dams could contribute to the Sustainable Development Goals while sustaining water used for operating them.
This piece was produced by SciDev.Net’s Sub-Saharan Africa English desk.