China has started construction of the world’s biggest hydroelectric dam, a project that’s set to be far larger than the Three Gorges Dam — already the world’s biggest single source of green power — and more expensive than the International Space Station.

The location in the remote and sparsely populated Tibetan borderlands has the potential to cause environmental and political ructions.

The project on a river that runs through Tibet and India downstream could dwarf the Three Gorges Dam when completed.