LCA of biomethane

As a renewable substitute for natural gas in the pipeline system, biomethane is a key option on the way to sustainable, renewable energy supplies. This paper evaluates biomethane production from energy crops with respect to its environmental impact and energy efficiency, taking into consideration own measurements and experience data from a modern, commercial plant as well as current studies. According to this study the specific GHG emissions associated with the production of biomethane amount to as little as 44.6 g CO2eq/kWh, corresponding to an overall GHG emission reduction of 82% compared with natural gas. The specific non-renewable energy demand of the entire process is very low at only 12%. These two indicators are due either to environmentally friendly plant cultivation (fermenter residues used as fertilizer) or to optimized plant design and operation (amine upgrading, renewable process heat, gas-tight equipment, industrial process control system).