Replacing fossil fuels with bioenergy in district heating – Comparison of technology options

We combine previously separate models of Northern European power markets, local district heating and cooling (DHC²2District Heating and Cooling (DHC).) systems, and biomass supply in a single modelling framework to study local and system level impacts of bioenergy technologies in phasing out fossil fuels from a DHC system of the Finnish capital. We model multiple future scenarios and assess the impacts on energy security, flexibility provision, economic performance, and emissions. In the case of Helsinki, heat only boiler is a robust solution from economic and climate perspective, but reduces local electricity self-sufficiency. Combined heat and power solution is more valuable investment for the system than for the city indicating a conflict of interest and biased results in system level models. Bringing a biorefinery near the city to utilize excess heat would reduce emissions and increase investment's profitability, but biomass availability might be a bigger limiting factor. Our results show that the availability of domestic biomass resources constrains bio-based technologies in Southern Finland and further highlights the importance of considering both local and system level impacts. Novel option to boost biorefinery's production with hydrogen from excess electricity is beneficial with increasing shares of wind power.