Development of a GHG-based control strategy for a fleet of hybrid heat pumps to decarbonize space heating and domestic hot water

In Europe, the building sector accounts for approximately 35 % of the energy-related emissions. Hybrid systems coordinating heat pumps and gas boilers can avoid greenhouse gas (GHG) emissions from carbonized electricity production by providing demand-side flexibility without any service interruption. This work aimed to develop a control strategy for a fleet of hybrid heat pumps to reduce GHG emissions. The electricity and gas consumption of a fleet of 3000 hybrid heat pumps, heating 100,000 dwellings spread throughout France, was evaluated. A Modelica model of a district archetype was simulated in seven cities representative of the French climatic zones to obtain the national heating demand. The marginal emission factor of the electricity consumption was assessed using a French power system model coupled with marginal emission factors for interconnected power systems, which were assessed through linear regressions. Two types of control strategies (prioritizing the heat pump and fuel switch) are evaluated considering 4 different sizing for the heat pump (120 %, 50 %, 35 %, and 20 %). Between July 2018 and June 2019, a strategy prioritizing the heat pumps would have avoided between 8000 and 26,000 tCO2eq for the power system. A strategy switching between the heat pump and the boiler based on the marginal emission factor of the electricity consumption would have avoided around 38,000 tCO2eq, with a limited influence of the sizing of the heat pump.