Marks & Spencer and Npower have today signed a landmark deal that will see the utility provide the retailer with enough renewable electricity to power all its stores and offices in England and Wales.

The six-year deal means Npower will provide M&S with 2.6TWh of renewable electricity from April this year. The move takes the retailer a large step towards reaching its target of sourcing 100 per cent of its electricity from renewable sources.

The bulk of the power will come from Npower's large-scale wind and hydropower projects, but the contract also includes a proviso designed to support small-scale renewables developers, including some of M&S' own suppliers.

The retailer already sources over 30 per cent of its electricity from renewable sources, including five small-scale projects, some of which are managed by farmers who supply the company.

Under the terms of the deal, Npower will take over the existing contracts and pledge to buy power from any other small renewables projects keen to sell power to the retailer.

Richard Gillies, director of Plan A at M&S, said that farmers interested in investing in small-scale renewables projects such as wind turbines and anaerobic digestion technologies "can be confident that M&S will purchase, via Npower, any renewable electricity they generate".

A spokeswoman for M&S said that the guarantee would make it easier for farmers to access loans to pay for renewable energy projects.

"Renewable energy is a great secondary revenue opportunity for farmers," she added. "They have the land and they can put up a wind turbine and still keep farming beneath it."

Grant Mackie, an Aberdeenshire farmer currently selling power generated by three wind turbines to M&S, welcomed the deal. He added that it should help farmers invest in renewable technologies. "Farmers are continually being advised to diversify, yet there are several barriers to investing in renewables and it can be a costly process," he said.