Greenspan contract hydroelectric turbine to supply M&S

Posted on 26 October 2011

The first hydropowered turbine to be built on the river Thames in recent times was unveiled today (25/10/11), taking over at the last working watermill still located on the river.

Mapledurham Estate on the banks of the Thames in Oxfordshire is now home to the biggest Archimedes screw in the UK – an update of millennia-old technology that will allow electricity to be generated from 280 Olympic swmming pools of river water washing through the turbine every day.

Several other hydropower plants have been proposed for the Thames, including one for the Queen at Windsor, but none are yet operational.

The 900-year-old estate – whose watermill was mentioned in the Domesday Book – already supplies milk to Marks & Spencer, and now renewable energy, providing the retailer with around 500,000kWh of renewable electricity each year, or enough to power one of its average stores.

John Eyston, owner of the estate, said the deployment of the hydropower technology was a long-held dream. He said: “It’s been our long-standing ambition to generate renewable electricity from the last working watermill on the Thames. We’re delighted that the hydropowered turbine is now up and running, providing a sustainable additional income for the future from this historic site.”

Converting old watermills to produce electricity can be tricky, in part because of the need to gain planning permission and to build in protection for fish. At Mapledurham, the system has been designed so that fish can swim safely through the machinery, which is 3.5m in diameter, and it should not break down if hit by flooding or debris. Work on the turbine begun in April and finished within six months.

Under its “plan A” project to be more environmentally sustainable, M&S is encouraging small suppliers, including farmers, to build renewable energy projects by guaranteeing to buy the electricity under a five year fixed price contract. This steady income stream helps the supplier to raise the finance needed for the upfront cost, and many of the schemes are also eligible for government subsidies under the renewable obligation or feed-in tariff schemes.

The watermill at Mapledurham Estate, which has been a favourite subject of British artists down the years, will be open to viewing by the public at certain times.

Martyn Bentley, Energy Contracts Advisor at The Greenspan Agency, has been working with M&S and the Eyston family to secure the deal.