Working alongside G2G technology, this would convert a nominal percentage of the captured biogas into electricity, which would be used to power the site’s lighting, de-packaging plant, air compressors and water pumps, with all surplus electricity sold back to the National Grid.
In addition to creating renewable electricity, heat produced by the CHP engine would also be utilised to firstly pasteurise the digestate, as well as keep it warm during the digestion process. This would ensure that the microorganisms present were kept at an optimum temperature – maximising the gas yield collected from recycling organic waste – as well as ensuring the resulting digestate could be repurposed as sustainable biofertiliser for local farmers.
As the generation of renewable electricity is subsidised by the government’s Feed-In-Tariff (FIT), installing the system would guarantee a token financial return – simply for generating energy via CHP. Combine this with the Renewable Heat Incentive (RHI) subsidy for generating and utilising renewable heat, as well as injecting biomethane directly into the National Gas Grid via G2G, and the true financial benefit of CooperÖstlund’s engine solution becomes clear.
Following Andigestion’s official opening earlier this year, the facility is now one of the only AD sites in the country to boast ‘island mode’, meaning that it can continue to operate even in the event of the National Grid going down.
Johan Östlund, director at CooperÖstlund, said “Although we typically fit and service gas engines on site looking to convert organic waste to electricity using CHP, working with Andigestion on such an innovative project demonstrated our capabilities on a more intricate scale.” He added, “Using electricity to power the site and heat to pasteurised the digestate ensures that Andigestion can run its entire operations via recycled waste – setting the standard for other facilities across the UK.”