Impact of temperature dependent coefficient of performance of heat pumps on heating systems in national and regional energy systems modelling

To successfully transition towards fully renewable energy systems, energy sectors that today are primarily autonomous should be closely integrated to increase system flexibility and maximise synergy from effective sector coupling. Heat pumps are one of the sector coupling technologies which enable a mutual integration of power and heat sectors. Heat pumps are viewed as a low-cost source of sustainable heat for both space heating and industrial processes. However, representation of heat pumps in energy system models is typically oversimplified by using a uniform coefficient of performance, which limits perception of the hourly temperature changes on heat pump efficiency, or by using generic heat pumps for all individual residential, district, or industrial heat supplies. The LUT Energy System Transition Model was expanded to examine the impact of utilisation of hourly coefficient of performance profiles and specific heat pumps for different applications. The results indicate that, in cold climate countries, the use of hourly coefficient of performance profiles has little impact on the heat supply structure and overall primary energy demand, but has a noticeable impact on the electricity supply and energy storage system. Though the cost of the optimised system stays on the same level, application of hourly COP profiles leads to a more accurate simulation of electricity consumption and energy storage operation. The separation of district and industrial heat pumps leads to a higher share of heat pumps in industrial heat supply and allows for a reduction in overall energy system primary energy demand by 1.8%.