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 dam will be built on Tibet’s longest river and despite concerns from India, Bangladesh and Tibetan rights groups, it has now been approved by central government. At a huge cost of £737million, once it has been completed, it could be the world’s largest hydropower dam.