The bank, noted for its ethical lending stance and other social policies, said the agreement that comes into force today will make it Britain's largest purchaser of green energy. With green power already in use at the London and Salford sites, nearly 40 per cent of the energy it uses comes from renewable sources.
Paul Monaghan, manager of Co-operative's ecology unit, said the initiative is helping the bank beat targets for reducing pollution and helping it to save money at the same time.
The project - under which electricity is produced by a turbine at the canal's Barton Dock - is run by ENER-G, a specialist producer of renewable energy, which sells it to the Renewable Energy Company, which in turn supplies the bank.
Dale Vince, managing director of the energy company, said he hoped other organisations would follow the bank's lead. "The greater demand, the more new `green generation' we can build," he said.