Installation of Small-Size Biomass-Fired CHP Units in Existing District Heating Systems

The sector of building heating in last years has seen an increasing interest in energy conversion efficiency and energy production from renewable sources. The amount of buildings supplied by district heating systems in northern Italy has doubled between 2000 and 2010. The main share of Italian District Heating (DH) is fuelled by fossil fuel CHP systems, and a smaller share relies on heat production from renewable sources. The increase of energy production from renewables is in line with the European targets set out in the Climate Package (20-20-20 targets) and with the recent debate on future targets for 2030. Moreover, the use of biomass-fired CHP systems could lead at the same time to an increase of primary energy savings with respect to separate production of heat and power. This study focuses on the benefits of installing wood biomass ORC units in existing DH systems. The primary energy savings and the energy share produced from CHP have been evaluated for different simulation scenarios, as well as a basic economic analysis considering the new Italian incentives on electricity production from renewable sources.