The research will create a hybrid anaerobic digestion process in which hydrogen made from renewable energy sources (e.g. wind and photovoltaics) is used to produce biomethane at more than 95% purity. The process therefore provides an efficient in situ biogas upgrading technique which will maximise the conversion of the available carbon in waste biomass into a fuel product that has a wide range of applications, including short-term storage for grid balancing and use as a vehicle fuel. The process is likely to be more environmentally friendly and sustainable than current methods for biogas upgrading as there is reduced process loss of methane. The target is to develop the system for use in the water industry where there is a large potential to integrate it into existing infrastructure and to maximise the use of process heat and other by-products. A second targeted application is at a smaller scale on farms, where there is an abundant supply of waste biomass and a lack of suitable biogas upgrading plant.