Large-Scale Quantification of the Future Self-Covered Heat Demand Using a Nationwide Residential Building Database

Abstract

Electrification of the residential heat supply through rooftop PV and air-source heat pumps is a key measure in the decarbonization of the German building stock. The potential of these technologies varies based on building properties, usable rooftop area, weather, and resident behavior. Using a building database and statistical data, we investigated how much of the residential heat supply in Germany could be covered independently by homeowners using air-source heat pumps, photovoltaics, batteries, and thermal energy storage. An energy system model was developed, and energy load profiles were generated for each house via a detailed bottom-up building simulation. Our results indicate that 33.5% of the average annual heat demand can be met with onsite supply. Grid savings are highest for well-refurbished single-family and terraced houses, at 32% and 34%, respectively. During cold periods, single-family and terraced houses achieve 13–84% grid savings, while in warm periods, they inject 102–300% back into the grid. Understanding the actual electricity consumption and grid contributions of buildings with solar-assisted heat pumps is crucial for accurately estimating future grid loads and planning local grid expansions. This information also helps homeowners and subsidy programs assess the benefits and drawbacks of these energy systems.

Keywords: building simulation, Heat Demand, heat pump, Rooftop PV, Self-sufficiency, Germany