The resource of biomethane, produced via biological, thermal and electrical routes, as a transport biofuel

Biomethane is an energy vector suitable for renewable transport fuel which may derive energy through three different methodologies: thermal gasification; biological anaerobic digestion; and conversion of electricity to hydrogen (via electrolysis) and on to methane as described by the Sabatier Equation. Thermal gasification to produce methane (based on " hard" feed stock) tends to require significant scale, of the order of 400 MW. Biological anaerobic digestion (based on " soft" feed stock) is typically of scale less than 1 MW. Systems based on the Sabatier Equation convert hydrogen to methane exothermically and sequester carbon. The resource is assessed at 19% of energy in transport in Ireland. Adopting the approach of the EU Renewable Energy Directive (for example double credit for biofuels from residues and lignocellulosic feed stock) biomethane can supply 40% renewable energy supply in transport (RES-T). The resource is sufficient to supply 30% of the private transport fleet with indigenous sustainable gaseous biofuel.