Assessing the impact of seasonality on bioenergy production from energy crops in Germany, considering just-in-time philosophy

Abstract

The availability of biomass is strongly influenced by seasonality, which can affect the production of biofuels, biogas, and bio-based products in the downstream bioenergy supply chain. Rapeseed, maize silage, sugar beet, wheat, and grass from grassland are the most popular energy crops; they play a significant role in the German bioenergy strategy and are being discussed extensively in the current gas shortage context. Most models in the literature assume yearly temporal resolution for these energy crops, which can negatively impact the accuracy of results. This problem is increasingly relevant under weather conditions that are varying increasingly due to climate change; in this study we therefore employ the extended bioenergy optimization model (BENOPTex) to explore the impact of seasonality on the optimal deployment of biomass from energy crops in bioenergy production in the German heat, power, and transport sectors, which typically show high dependency on fossil fuels. First, we increased the model's temporal resolution using available datasets and documents. Next, the varying availability factors were embedded in the optimization model, considering the no-storage policy for energy crops in accordance with the just-in-time philosophy. Finally, the outcomes of the BENOPTex with annual resolution were contrasted with the results including the effects of seasonality, while considering various objective functions. We demonstrated a shift toward the consumption of woody biomass until 2045 due to its longer shelf life and improved storability. The energy demand stemming from summer leisure travel was also anticipated to exceed the bioenergy system's capacity. The insights provided here might be interesting for policymakers who design roadmaps for bioenergy development with a more resilient energy supply.