Alas, this is absolutely right. It's trivial to find places to put hydropower using global elevation data and GIS tools, but almost all of the good ones are alr

Alas, this is absolutely right. It's trivial to find places to put hydropower using global elevation data and GIS tools, but almost all of the good ones are already either being exploited, or in the process of being readied for use, or facing barriers such as the side-effect of destroying cities or heritage sites.