The state of North-Rhine Westphalia is set to turn its Prosper-Haniel hard coal mine in Bottrop into a 200 MW pumped-storage hydroelectric plant.

The facility will act like a battery and will have enough capacity to power more than 400,000 homes, according to state governor Hannelore Kraft.
Prosper-Haniel
Other mines may also be converted after Prosper-Haniel because the state needs more industrial-scale storage as it seeks to double the share of renewables in its power mix to 30 per cent by 2025, she said.

North-Rhine Westphalia generates a third of Germany’s power.

The consortium running the Prosper-Haniel project, which includes the University of Duisburg-Essen and mine owner RAG AG, are confident that the mine is suitable to become a storage pump.

The plan to reinvent Prosper-Haniel envisages creating reservoirs above and below the closed mine, according to a blueprint posted on the group’s website.

When needed to compensate intermittent wind and solar power, as much as 1 million cubic meters of water could be allowed to plunge as deep as 1,200 meters, turning turbines at the foot of the colliery’s mine shafts. The mining complex comprises 26 kilometres (16 miles) of horizontal shafts.