Assessing the Contribution of District Heating to the Flexibility of the Italian Power System in High Renewables Penetration Scenarios

In compliance with Paris Agreement decarbonization targets, the EU goal is to reach carbon neutrality by 2050. This will put particular pressure on the power system, and will require enough flexibility to cope with high shares of renewable energy sources (RES) while ensuring the security and affordability of the service. In this regard,the penetration in the energy system of heat-electricity sector coupling technologies is considered a promising solution for the integration of flexible devices such as thermal storage units and heat pumps. This would also enable the decarbonisation of the heating sector, responsible for around half of the energy consumption in EU 75% of which supplied by fossil fuels. This paper investigates in which measure the diffusion of district heating (DH) coupled with thermal energy storage (TES) units can contribute to the overall system flexibility and in particular to the potential provision of operating reserves for energy systems with high RES penetration. The deployment of two different DH supply technologies, namely combined heat and power units (CHP) and large scale heat pumps (P2HT), is modelled and compared in terms of performance. The case study analysed is the Italian energy system, which is simulated through the open-source unit commitment and optimal dispatch model Dispa-SET. Results show that the large deployment of DH systems coupled with TES units can offer an important contribution to the power system flexibility and to the provision of operating reserves. In particular,the large deployment of DH supplied by P2HT technologies can bring significant benefits in terms of system costs (up to 50% reduction), renewables integration and greenhouse gases (GHG) emission reductions.