Abstract
Due to the new carbon neutral policies, many district heating operators start operating their combined heat and power (CHP) plants using different types of biomass in stead of fossil fuel. The contracts with the biomass suppliers are negotiated months in advance and involve many uncertainties from the energy producer's side. The demand for biomass is uncertain at that time, and heat demand and electricity prices may vary drastically during the planning period. Furthermore, the optimal operation of combined heat and powerplants has to consider the existing synergies between the power and heating systems.