Friends of the Peak District's Peak Power report urges developers to focus on spots with the highest capacity and least planning constraints. These include Chatsworth's weirs and mills at Litton, Cressbrook, Calver, Rowsley, Baslow and Lumford in Bakewell.

Planning head Andy Tickle said: "The Peak District's the perfect place for small-scale hydropower. There's plenty of rain and fast flowing rivers running down from the hills.

"We've a rich legacy of water power - most places we looked at were old watermills. They're absolutely ripe for redeveloping."

Researchers, funded by the Peak District National Park Authority, probed 162 sites and found almost half could be viable renewable power stations.

National park chairman Narendra Bajaria said: "This report is an important stepping stone. It will encourage residents, community services, businesses and others to consider harnessing water power as part of a move towards more sustainable lifestyles."