Governance of sustainability in the German biogas sector—adaptive management of the Renewable Energy Act between agriculture and the energy sector

Biomass is an integral part of the energy system being not only used in the chemical industry, but also as a basic raw material for the bio-economy sector, which is promoted worldwide. However, its potential can only be exploited sustainably if biomass is cultivated and governed appropriately. Consequently, governance systems are needed to ensure sustainability throughout the bioenergy value chain to maximise the benefits and minimise possible negative impacts. This study investigates how sustainability is put into effect in the German biogas market, the largest biogas market worldwide. The development of Germany’s biogas market is described according to the structure of a four-phase market model of Heuss: the introduction, expansion, maturing, and stagnation phase. Within each of these market phases, the most important German legislation for development of the biogas market was analysed, namely the Renewable Energy Act and legislation addressing associated sustainability issues. The development of the biogas market was controlled and steered by the adaptive Renewable Energy Act, particularly by incentivising cultivation of energy crops. Efforts to promote sustainability started during the transition from market expansion to market consolidation. The effects of these efforts on greenhouse gas emission reductions have been monitored and reported for more than 15 years, but assessment of other aspects of sustainability has varied. In general, legislation regulating the agriculture sector was changed to address new sustainability concerns with some delay. Sustainable development of the agricultural biogas market requires elements of governance, including adaptive legislation within the energy sector as well as monitoring and regular reporting of environmental impacts and related developments in areas of the agriculture sector, such as meat production. Rapid growth of capacity in the biogas sector combined with a significant increase in meat production, dependent on increased fodder production, created risks to sustainability. It can be concluded that the sustainable development of biogas requires additional instruments, possibly national regulation, in addition to legislation applied to the broader agricultural sector.