Combined Heat and Power Plant and District Heating and Cooling Network: A Test-Case in Italy With Integration of Renewable Energy

The 2012 European energy efficiency directive supported the development of cogeneration combined heat and power (CHP) and district heating and cooling (DHC) networks, stressing the benefits of a more efficient energy supply, the exploitation of recovered heat, and renewable resources, in terms of fuel consumption and avoided costs/emissions. Policy decisions play a crucial role: technical and environmental feasibility of CHP is clear and well demonstrated, whereas economic issues (fuel prices, incentives, etc.) may influence its actual application. In this framework, the introduction of low-carbon technologies and the exploitation of renewable energies are profitable interventions to be applied on existing plants. This work focuses on a small CHP plant, installed in the 90 s and located within a research facility in Italy, designed to supply electricity and heat/cool through a district network. On the basis of monitored consumption of electricity, heating, and cooling, energy fluxes have been analyzed and an assessment was performed to get a management profile enhancing both operational and economic parameters. The integration of renewable energies, i.e., solar-powered systems for supporting the existing devices, has been evaluated, thus resulting in a hybrid trigeneration plant. Results demonstrate how the useful synergy between CHP and DHC can not only be profitable from the economic point of view, but it can also create conditions to considerably boost the integral deployment of primary energy sources, improving fuel diversity and then facing the challenge of climate change toward sustainable energy networks in the future.