Prof. Andrea Castelletti and researcher Matteo Giuliani from the Department of Electronics, Information and Bioengineering of the Politecnico di Milano are among the authors of a study published in Science according to which most of the new dams proposed all over Africa should not be built. Angelo Carlino, a former student of the Ph.D. program in Information Technology at the Politecnico di Milano and currently post-doctoral researcher at the Carnegie Institution for Science in Stanford, also contributed to the research along with colleagues from the Institute for Applied Systems Analysis (Austria), the Vrije Universiteit Brussel (Belgium) and the World Resources Institute in Addis Ababa (Ethiopia).
The research used a very detailed energy model to identify the most cost-effective combination of energy sources with which African countries could meet the growing demand for electricity until 2050 and, in particular, which plants could be a clever investment and which should instead not be built.
According to the analysis, up to 67% of possible future hydropower plants in Africa are not worth the investment, mainly due to the fact that hydropower will soon no longer be economically competitive as compared to solar power or (to a lesser extent) wind power, the costs of which have fallen at an unprecedented rate over the past ten years. However, especially in the Congo, Niger and Nile Basins, there are projects that are worth implementing in the short term, provided they are well planned and their harmful environmental effects are minimised.
The study also points out that further investments will be needed to mitigate the effects on hydropower of prolonged droughts, which are likely to worsen due to climate change. This is another reason why solar energy will emerge as the most appealing technology in the long run, to be prioritised in most African countries.
The results of the study are generally good news for the environment: it means that fewer dams will be built and therefore many rivers will be able to maintain their natural course.