Sector-coupling in Renewable Energy Communities: Impact on Heat Pumps Providing Flexibility
Renewable energy communities enable local sharing of electricity and heat. This study evaluates the impact of sector-coupling in a rural Austrian housing cooperative transitioning to a renewable system with photovoltaic generation, a fifth-generation district heating and cooling network, borehole thermal storage, wastewater heat, and decentralized heat pumps. Using the open-source optimization tool IESopt, two scenarios are compared for one year: a baseline where heat pumps follow thermal demand, and a sector-coupled case where operation shifts to periods of surplus PV. Both scenarios identify a large seasonal BTES (~120 MWh) as essential, covering over half of annual heat demand. The sector-coupled scenario reduces total system costs by ~10.5% through improved use of low-cost community electricity and coordinated flexibility. Heat pumps operate more dynamically—about 16% more activations with 15–20% shorter durations—and show reduced full-load hours due to higher installed capacity. Although sector-coupling increases peak electric demand, it substantially improves economic and operational performance. Overall, sector-coupling combined with moderate thermal flexibility provides an effective and cost-efficient pathway for decarbonizing community-scale energy systems supported by seasonal storage.