Evaluation of heat pumps CO2eq-emissions based on dynamic electricity emissions factors

Heat pumps are recognized as a key technology for decarbonization. However, many studies assessing heat pump emissions rely on static emission factors, which do not account for the variability in electricity sources. The objectives of this study are a) to assess the difference in emissions by using static annual and dynamic (15-minute) emission factors for electricity and b) to compare emissions of heat pump systems with those of gas boilers in residential heating applications in Germany. Using the simulation software Polysun, historical weather data, and quarter-hourly emission factors, emissions from three heating systems were determined in four reference buildings for the years 2024 and 2019. Results confirmed that dynamic calculations yield emissions 15% higher than with a static emission factor for heat pumps, yet these emissions remain more than 60% lower than those from gas boilers. The integration of PV in the investigated building reduces emissions by up to 20%, achieving up to 27% self-sufficiency. In 2024, the simulated heat pumps utilized about 50% renewable energy, a trend projected to increase with growing renewable capacity in the coming years.