"It is a mechanical problem that has troubled scientists since Archimedes and the ancient Greeks, but now a Scottish electrician has come up with the answer - and it could help consumers save thousands of pounds in energy bills.
Ian Gilmartin, 60, has invented a mini water wheel capable of supplying enough electricity to power a house - for free.
The contraption is designed to be used in small rivers or streams - ideal for potentially thousands of homes across Britain.
It is the first off-the-shelf water-wheel system that can generate a good supply of electricity from as little as an eight-inch water fall. "
Read moreA portable, water powered computer anyone?
