Low-Cost Green Gas

Project Description

The importance of biogas to reduce the carbon intensity of the gas network is well recognized in Ireland's decarbonization effort. However, in current practice over 90% of the mass of biomass that enters an anaerobic digestor (‘AD’) unit ends up as digestate. This represents a massive missed opportunity for further value generation. Typically, less than 5% of the mass of incoming feed-stock is converted to useful biogas energy. On account of the extremely diffuse and slow-release nature of AD, developers require extremely high storage volumes and CAPEX to justify project economics. This creates a precarious situation where a dependence on subsidies, carbon pricing and large / multiple supply contracts are needed. This also limits small-medium scale entrants to the market, located in closer proximity to the biomass source. This situation can be avoided, and energy security enhanced, with the application of well proven thermal pyrolysis technology, unlocking more energy in partnership with AD systems. The objective of this project is to harness the full green power potential of digestate that emanates from AD units, via pyrolysis. Digestate is typically land-spread, a practice which is controversial in the EU on account of ground water contamination risk, pathogens etc. The continued dependence on this practice comes with regulatory risk. Also, digestate material releases significant GHGs in the form of methane as it further decomposes, which would be better utilised to bolster the existing AD facilities gas supply. Existing biomethane upgrading facilities on AD sites could be further utilised and / or upgraded to tie-in synthetic methane from the pyrolysis of digestate, with minor investment. The aim is to compete with cheap fossil fuels and ultimately deliver the lowest green €/MW available.