Cost-effective biogas utilisation – A modelling assessment of gas infrastructural options in a regional energy system

The current utilisation of biogas from anaerobic digestion is low compared to the technical potential. This study investigates requirements for policy support to overcome techno-economic barriers of biogas utilisation and effects of different biogas distribution strategies. Two potential sectors for biogas use are covered: the transport sector and the district heating sector. A quantitative, optimising, energy system modelling approach is applied and the region of Vastra Gotaland, Sweden, is studied. The model has a high geographical resolution and locations of both biogas feedstock and potential markets are taken into account. The results show that a small part of the technical biogas potential can be cost-effectively utilised without biogas subsidies or larger infrastructural investments. Comparably low subsidies give significant increases in cost-effective biogas utilisation levels, but utilisation close to the full technical potential is linked to high subsidies. From a techno-economic perspective, biogas is best used as vehicle gas. Since local vehicle gas markets are limited, enhanced biogas distribution conditions not only imply larger total cost-effective biogas utilisation, but also a larger share of biogas as vehicle gas. Compared to distribution strategies based on truck transports and regional biogas grids, an expanded natural gas grid presents possibilities but also risks.