Reasonable potential for GHG savings by anaerobic biomethane in Germany and UK derived from economic and ecological analyses

This study introduces a new approach to estimate biomethane market potential by analysing biogas markets and their relative environmental and economic advantages. This potential is then combined with greenhouse gas emission values for different feedstock shares (farm-fed and waste-fed systems) and different application share to determine the possible contribution of biomethane to national greenhouse gas emission saving goals. Markets that are considered are Germany and the UK being the biggest emitters of CO_2eq in the European Union. The current use was compared with the scenarios (i) market projection, derived from literature study and (ii) reasonable potential, derived from environmental and economic calculations. The current market status is presented to show the past market development until the present date and associated greenhouse gas savings. Additionally the potential of biomethane to contribute to greenhouse gas emission savings is extensively described. Results indicate that the share of application in Germany is more environmental beneficial than the one in the UK achieving higher greenhouse gas savings at comparable feed-in level. In contrast, the UK has a higher share of waste-fed systems to produce biomethane. The use of biomethane in CHP plants achieves the highest GHG emission savings and if organic waste is used as feedstock the possible savings are even higher. With an increase of biomethane used in CHP plants and a decrease of biomethane used for direct heating the savings in the UK could increase up to 52%. Current savings of 2446 kt CO_2eq (Germany) and 606 kt CO_2eq (UK) can be extended to 4483 kt CO_2eq (Germany) and 1443 kt CO_2eq (UK) respectively. Scenario results were determined based on the environmental and economic advantageousness development of the existing biogas market. In this way positive future market development as well as improved shares of feedstock and application can contribute to further greenhouse gas emission savings of Germany and the UK.