In the Heat of the Moment - A modelling exercise of power and heat system interactions in a renewable energy future

Abstract

The integration intermittent energy sources (IRES) in the electricity system poses challenges related to the variable production of IRES. Integration of the electricity system and the heating system through power-to-heat (P2H) interactions, can help overcome these challenges. This research studies whether and how these linkages could lead to reductions in total system costs and carbon dioxide (CO2) emissions with large IRES deployment. In this study, the PowerFys model was expanded in order to model the whole heating system of a country and all its interactions with the electricity system. In the new model, it is possible to model: (1) inter-system interactions such as P2H conversions; (2) combined heat and power (CHP) generation; and (3) seasonal thermal energy storage (STES). Several scenarios were tested for the Netherlands in the years 2030 and 2050. In the scenarios the deployment of heat pumps and connections to district heating (DH) were varied. The influence of electric boilers and STES connected to the district heating were studied as well. The electricity system was assumed to become increasingly dependent on renewable energy sources and was similar for all scenarios of the same year. Under the assumptions in this study, the scenario with the highest deployment of heat pumps resulted in the lowest system costs in 2030 and 2050. In 2050, this scenarios resulted in savings of little over 2 billion euros annually compared to the 14 billion euros of annual Dutch system costs in the baseline scenario. Additionally, the CO2 emission reduction was the largest with 22.7 MtCO2/yr compared to 30.8 MtCO2/yr in the baseline. It was found that the flexible dispatch of heat pumps and CHP units resulted in these savings. It was shown that the capacity of both electric boilers and STES can increase system costs of district heating with 1 billion euros per year. However, it is possible that carefully balanced capacities of electric boilers and STES can also reduce the system costs of district heating. This research showed that next to electricity and heat system integration, additional savings of 8 MtCO2/yr are required to achieve a fully renewable Dutch heating and electricity system in 2050. Integration of IRES can be achieved with the deployment of heat pumps at the lowest system costs and with the highest emission reduction. The innovative method, as presented in this thesis, can also be used for future research on the integration of other energy systems as well as further research on electricity and heat interactions.