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

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.

At over 4,000 metres above sea level on the Yarlung Tsangpo, Tibet’s sacred river that becomes the Brahmaputra in India, the dam includes a system of five cascading plants that will produce enou