If you've got a small stream (as little as 20cm wide) near your house and hate to pay the electric bill, just wait for this new invention:
The prototype has now been working successfully at St Catherine's, a National Trust site near Windermere, opening up previously untapped energy. The waterwheel produces one to two kilowatts of power and generates at least 24 kilowatt hours of sustainable green energy in a day, just under the average household's daily consumption of around 28 kilowatt hours. [...]
A 'high head' like a traditional water-wheel, is large, expensive and needs civil engineering. But with 'low heads' - under a 18 inches, no one had yet invented a method of successfully recovering the energy generated.
Link - via Gadget Reporter