Biogas Plant Modelling for Flexibility Provision in the Power System of Bornholm Island

Biogas power plants play a vital role in the structure of integrated energy systems to further decarbonize the energy sector. On the one hand, they can facilitate the broad integration of variable renewable energy sources; on the other, they directly interlink different energy domains and provide multi-energy services. This paper provides an overview on the possibilities and potentials of biogas power plants in providing flexibility towards islanded power systems. To this end, we present a model that includes the most relevant dynamics from an electrical engineering perspective. For a given infeed of raw material, it is able to characterize the anaerobic digestion processes and quantify the energy output in order to evaluate the plant's flexibility potential. The model is validated against real data from a 3-MW biogas power plant on the island of Bornholm, Denmark. The results show that actual on-site measurements in terms of biogas production as well as electrical and thermal output may be matched by the presented model. Furthermore, the paper gives a detailed overview on the estimated biomass potential of the island of Bornholm, as well as the flexibility assessment of the entailed biogas operations.