Demand for the flexible provision of bioenergy carriers: An overview of the different energy sectors in Germany

Abstract

Today bioenergy is the most important renewable energy carrier in Germany and yet it is mostly provided constantly as a base load, for example most biogas plants are in constant production at full load. In numerous ways, bioenergy could be a flexible option to satisfy the fluctuating demand for electricity, heat and transport fuels. In the power sector, biomass is a short-term option to meet the increasing need for flexible power generation, while wind or solar power are characterized by an alternating feed-in. Biogas plants in particular are ideal for providing power on demand for a stable electricity provision with a high percentage from renewables. The heat sector is well established for heat only provision, but has to integrate future combined heat and power concepts. Therefore, an optimal alignment between heat and power generation is required, if a high overall performance is to be achieved. Furthermore, the general decrease in heat through efficiency measures will change the way in which heat will be generated with more versatile load curves where flexible energy provision is favoured. In the transport sector flexibility is necessary in the form of a varying feedstock basis for consistent liquid biofuel products. For example, bioethanol could be made from sugar beets or cereals, where sugar, or starch converted into sugar, is processed by fermentation into alcohol. Second generation bioethanol is based on cellulose enzymatic split into single sugar molecules. Additionally, biomethane as a potential substitute for natural gas can be applied in different sectors and is predestined for flexible energy provision. A local and temporal decoupling of energy source generation, the well-established gas grid and the interchangeability with natural gas are all aspects that support this. It is expected that the different markets for power, heat and fuels will be more closely linked by the mid term. Here, some additional combinations of bioenergy with other renewables (i.e. power-to-gas) can provide flexible energy in different sectors additionally.