Poorly estimated potential
Up to now most information about hydropower was obtained via surveys from national governments. In many cases the research method was unknown and the quality varied. Researchers from Utrecht University have made considerable improvements in this, with a consistent methodology that utilises extremely high resolution maps to assess almost four million individual sites across the globe. In this way the researchers identified over 60,000 suitable sites which together represent a potential supply of 9.49 PWh/yr (petawatt hours per year). By comparison, global energy consumption in 2016 was around 20 PWh/yr.
Pros and cons
In more developed regions, such as Europe and North America, the existing surveys give a fairly accurate picture of hydropower potential, but this is not true of developing regions such as Africa and Asia, for which almost no good data are available. The researchers in Utrecht show that in Africa, South America and Asia, there is potential to produce around 5 PWh/yr at low cost. However, there are some disadvantages to hydropower, in the effects on biodiversity and man. For example, some water reservoirs produce methane, which has a negative effect on the climate. In their study, the researchers only focused on the energy potential, but they feel that their new insights are of value in finding balanced solutions that take into account the impact on climate, man and biodiversity.
Input for climate studies
"For these assessments, we used very detailed maps showing hydrological data”, says energy researcher David Gernaat of Utrecht University, the main author of the article. “Alternative assessments were either transparent or less detailed. Working at both the Netherlands Environmental Assessment Agency (PBL) and Utrecht University enables me to identify research questions that are relevant to policy and to develop methods to answer these questions."
PBL and Utrecht University work together on this kind of integrated assessment study and explore response strategies for climate change. Professor Detlef van Vuuren, who worked with David Gernaat on this study, confirms: "This new information on hydropower will be widely used for global energy models, including those from the International Panel on Climate Change (IPCC)."
Gernaat, David EHJ, Patrick W. Bogaart, Detlef P. van Vuuren, Hester Biemans, Robin Niessink. (2017). High-Resolution Assessment of Global Technical and Economic Hydropower Potential. Nature Energy. doi:10.1038/s41560-017-0006-y