British retailer Marks & Spencer has signed a deal to get green energy from an anaerobic digestion plant.

The power supply deal – known as a Power Purchase Agreement or PPA – means M&S will get 30,000 megawatt hours (MWh) worth of electricity from waste management firm Shanks.

That’s enough to power 20 of its Simply Food stores.

Shanks’ anaerobic digestion or “AD” plant in Westcott, near Bicester takes food waste that can’t go to food banks and converts into biogas and soil conditioner.

Giacinto Patellaro, Head of Energy Supply & Risk at M&S said: “Having advocated the use of AD technology since the launch of our sustainability programme, Plan A, back in 2007, we’re now seeing in practice how these deals are helping M&S to maintain two of our targets: to procure 100% renewable electricity and send zero waste to landfill.”

It’s the second such deal between the two businesses – as M&S already takes renewable energy from Shanks’ AD facility in Cumbernauld.