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Water and waste company Severn Trent has been using leftover Halloween pumpkins to generate electricity at its two food waste power plants in the Midlands. 

With Halloween now no more than a spooky memory, unwanted or uncarved pumpkins have been arriving at its food waste plants in Stourbridge and Coleshill, where staff will adding them to the mix of out of date and inedible food waste that it uses to generate clean electricity and gas, while also helping to cut down on waste.   

Peter Rhodes, Renewable Energy Operations Manager at Severn Trent, said: “Most people probably don’t know what to do with unwanted pumpkins after Halloween but, for us, it’s just another thing we can add to the mix at our food waste plants where we can convert them into clean, green electricity and gas for thousands of homes. 

“It’s always good to know we can make use of things that would normally just be thrown away because they can’t be eaten.” 

Turning food into energy involves a complex process. Firstly, lorries empty food waste into a specialist machine which removes all plastics and packaging. The second phase sees the anaerobic digestion process taking over which is where the food waste is ‘digested’ in the equivalent of a giant stomach, producing methane gas which rises to the top of large, secure storage tanks. After around 90 days, the gas produced is then turned into green energy, either as electricity through a combined heat and power machine, or as green gas that is fed into the national grid for nearby homes and businesses. 

Severn Trent’s anaerobic digestion plant in Stourbridge produces around 28GWh of energy every year, while its sister plant in Coleshill produces 20GWh annually. Together they produce enough energy to power over 9,000 homes for 12 months. 

Severn Trent’s third site in Derby will officially open next year, and the company recently bought five food waste anaerobic digestion plants and five green and comingled waste composting sites from Agrivert as the company looks to produce the equivalent of 50% of its energy usage from renewable sources by 2020.