Production of district heat, electricity and/or biomotor fuels in renewable-based energy systems

Abstract

We analyze the possibilities to produce district heat, electricity and/or biomotor fuels in renewable-based energy systems considering district heating systems with annual heat demands between 110 and 1000 GWh. Several technical configurations to co/polygenerate district heat, electricity and/or biomotor fuels are cost optimized in the context of different standalone production options, woody biomass fuel prices and integrating costs of intermittent energy resources. The cost optimum configuration varies with the scale of the district heat production, as does the use of biomass to generate the same amount of product, and both depend on the context of the overall energy system. There are several state-of-the-art technologies that offer significant co/polygeneration benefits within district heating systems. An electric-based solution for transportation as well as an electric-based option for small-scale district heating systems are cost efficient and will reduce the use of biomass and help to integrate wind electricity into the overall energy system. For larger district heating systems, cogeneration of heat and electricity, and also in combination with electric heat pumps for a high biomass price, are cost efficient solutions. Further studies are needed, for example to understand how the deep energy renovation of buildings may influence the configuration of co-/polygeneration systems in district heating systems and potential savings of woody biomass.