The controversial role of energy crops in the future German energy system: The trade offs of a phase-out and allocation priorities of the remaining biomass residues

Abstract

Multiple global crises are adding new elements to the discussion on securing and shaping a resilient, renewable energy system in Germany. Biomass from residues, forest wood and energy crops are major renewable energy contributors in Germany today. The role of energy crops within that system is controversially discussed for a long time and a phase-out from cultivated biomass is again in the focus. But what kind of trade-offs would be connected with such a phase-out and what would be the optimal allocation priorities of the remaining biomass potential? Through a detailed representation of biomass potentials, prices and conversion technologies in an energy system optimisation model, it could be shown in a scenario analysis that a phase-out increases the demand for energy imports by 1400 PJ per year, which is associated with on-costs of €14–25 billion annually in the long term. Finally, the results show that the decision on whether to grow energy crops in the future is directly influencing the future transformation strategy for high-temperature industrial heat applications. Solid biomass is identified as the future cost-optimal solution to fully transform this sector. However, a phase-out of energy crops changes the cost-optimal allocation priorities completely.