Limiting biomass consumption for heating in 100% renewable energy systems

The utilisation of biomass poses large challenges in renewable energy systems while buildings account for a substantial part of the energy supply even in 100% renewable energy systems. In this paper the focus is on how the heating sector can reduce its consumption of biomass, thus leaving biomass for other sectors, but while still enabling a 100% renewable energy system. The analyses of heating technologies shows that district heating (DH) systems are important in limiting the dependence on biomass and create cost effective solutions. DH systems are especially important in renewable energy systems with large amounts of fluctuating sources as it enables fuel efficient and low cost energy systems with thermal heat storages. DH increases the efficiency with the use of combined heat and power production (CHP), while reducing the biomass demand by enabling the use of other renewable resources such as large-scale solar thermal, large heat pumps, geothermal heat, industrial surplus heat, and waste incineration. Where the energy density in the building stock is not high enough for DH to be economical, geothermal heat pumps can be recommended for individual heating systems, even though biomass consumption is higher than the DH solutions.