There are around 1.2 billion people in Africa, and most of them need more energy than they're using now. The person in Africa uses four times less energy than the global average, but as African nations improve their standard of living, they are starting to use more and more electricity. Hopefully, the vast majority of that new energy will be renewable and clean — and indeed, that's the plan for much of the African continent, with hydropower at the forefront.
But the plan is changing.
Hydroelectric dams, once considered to be a prime source of future African energy, may no longer be cost-effective.
At least on paper, the case for hydroelectric energy seems very strong in Africa. Abundant rainfall, massive rivers, and huge waterfalls — the geography of the continent seems to be excellently fit for hydropower. Many countries are already using this. Ghana's Lake Volta (the largest artificial lake in the world), Ethiopia's flagship Renaissance Dam, and the Aswan Dam (the largest embankment dam in the world) in Egypt are already huge, completed projects.
But Africa is only exploiting around 10% of its hydropower potential, and there are plans to build way more hydroelectric projects. Except those plans may not be all that wise.
According to a new modeling study, investing in more hydroelectric projects may not be the wisest approach for Africa.
The researchers looked at what would be the most cost-effective way for African countries to meet their rising energy demand by 2050. They looked at various sources of energy (hydropower, solar, wind, nuclear, natural gas, coal, and others), comparing their cost. They also estimated the cost and benefits of every possible future hydropower in Africa.
The study's complexity is unprecedented. They included everything from population growth to river flow and interplay between different plants. Ultimately, they found that in many cases, it's better to simply not build the hydroelectric plants. In fact, 67% of possible future hydropower plants in Africa are probably not worth the investment.
For now, renewables still account for a very small percentage of Africa's energy. But this stat could start to change soon.
"What is unique about our study is that we model every single hydropower plant in Africa individually — both existing ones and future candidates," explains Dr. Angelo Carlino, lead author of the study. "This way, our model can pinpoint which plants could be a smart investment and which ones should probably not be built."
The first reason is that renewable sources (especially solar, but also wind) are becoming cheaper. Simply put, hydropower will be unable to compete economically with other renewable sources of energy. Solar, in particular, is expected to become the cheapest form of energy for Africa.
But there's another reason why hydropower may not be as cost-effective: climate change.
Climate and water
We're already seeing the effects of climate change, but in the next couple of decades, these effects will almost certainly intensify. Drought is among the most prominent such effects — and drought is a game changer for hydropower. Drought makes river volume less reliable, and it also means you need to invest more into maintaining the plants.
This is another reason why solar power will emerge as the more attractive technology in the long term," says Dr. Matthias Wildemeersch, a research scholar at the International Institute for Applied Systems Analysis (IIASA) in Austria and co-author of the study.
But this doesn't mean it's "game over" for hydropower in Africa. At least in the short and medium term, some hydroelectric plants could provide much-needed cheap power. They could also be used as a buffer in the transition to renewables — essentially serving as a cost-effective bridge to reliable wind and solar.
"Our model shows which specific hydropower plants would still be cost-effective in the short-term," comments Professor Andrea Castelletti, professor in Natural Resources Management at Politecnico di Milano and senior author of the study. "Especially in the Congo, Niger, and Nile basins, there are certain projects that would be worth the effort, as long as they are well-planned and harmful environmental effects are kept to a minimum."
However, the study forces African countries to rethink how they should use hydropower.
"The window for hydropower in Africa to be a feasible investment is very rapidly closing," adds Professor Sebastian Sterl, professor in Energy Meteorology at the Vrije Universiteit Brussel (VUB), Belgium, and senior scientist at the World Resources Institute (WRI) in Addis Ababa, Ethiopia. The study suggests that beyond 2030, only a very limited number of hydropower plants would remain attractive investments across Africa. "Aside from cost-effectiveness, this is generally good news for the environment: it means that many rivers won't have to be dammed and can keep their natural course," concludes Sterl.
Solar will be king
In addition to showing the roadblocks for hydropower, the study highlights how dominant solar power is expected to become.
In the long term, solar power would emerge as the "king" of electricity markets world wide. Solar power is already the cheapest form of electricity globally, and there's still plenty of room for improvement, particularly as renewable energy is scaled up.
"The benefit of rapid renewable deployment is greater energy security androcky independence, plus long-term energy price deflation because this is a manufactured technology — the more you install the cheaper it gets," Kingsmill Bond, Senior Principal at the Rocky Mountain Institute, told Euronews earlier this year.
Journal Reference: Angelo Carlino et al, Declining cost of renewables and climate change curb the need for African hydropower expansion, Science (2023). DOI: 10.1126/science.adf5848