‘Flat pack’ waterwheel begins to generate electricity

The 4 metre diameter, overshot wheel produces 6kW of power from a continuous water flow of 200 litres/s at The Langdale Hotel and Spa near Ambleside in the English Lake District.

The waterwheel is built to a high specification, based on research and development Smith Engineering undertook with the University of Cumbria on bucket design and efficiency.

It has been positioned where there was an existing water supply in one of the wheel pits of the former gunpowder works, adjacent to The Langdale Estate’s original turbine house, which generated electricity for the estate in the 19th century. 

Delivery to site as a flat pack kit enabled it to be installed without the need for a large crane.  The buckets, spokes, rims and fishplates were all fabricated from cost-effective, 3mm pre-galvanised sheet.  These lightweight components were easily and rapidly assembled using nuts and bolts without the need for welding or any special tools on site.  This unique feature allows it to be installed in other remote locations where there is limited access. 

Since the wheel was installed in the summer, Smith Engineering carried out trials with Dr Paddy Quinlan from the University of Cumbria to determine its efficiency. The results show that high mechanical efficiencies can be achieved from overshot waterwheels.

A water to wire efficiency of around 75 percent was expected but first trials indicate it is nearer 80 percent. Payback at this rate should be around five years. David Postlethwaite from Border Hydro designed the control panel and grid connection.

"Little is known about the efficiency of electricity generating waterwheels at this scale," says Smith Engineering managing director, Rod Smith. "We are very pleased with the findings of the research undertaken with the university and its contribution to understanding this form of renewable energy.  It couldn't have been done without the backing of the university, Border Hydro and the exceptional team at Langdale Estate."

The waterwheel was funded through the University of Cumbria’s Renewable Energy Test and Education Centre (RETEC) with funding from Britain’s Energy Coast in partnership with the Nuclear Decommissioning Authority.