The industry has been shifting towards smaller projects.

China Three Gorges turned on the first set of generators at the massive Wudongde hydropower plant, deep in the mountains of Yunnan province. About 170 km downstream on the Jinsha River sits Baihetan, the last of its kind, scheduled to go into operation next year.

They’re the final two mega-dams in a Chinese construction boom that goes back more than half a century, one that became increasingly mired in controversy over the trade-off between the benefits of renewable energy and flood prevention and the social and environmental costs.

Now, China’s hydro industry is down-shifting toward smaller projects and pumped storage. Engineers have run out of the easiest locations to power massive sets of turbines and the falling cost of rival energy sources such as solar meant that it wasn’t worth moving on to more challenging locations.