Decarbonization of the Heating Sector in Hamburg Grid Constraints, Efficiency and Costs of Green Hydrogen vs. Heat Pumps

Germany’s path to climate neutrality is mapped out in the Climate Protection Act. Following the ruling of the Federal Constitutional Court on April 29, 2021, and with a view to the European climate target for 2030, the German government presented the amended Climate Protection Act on May 12, 2021. By this law, the heating sector in Germany is bound to reduce its CO
2
emission of 118 million t in 2020 to 67 million t CO
2
in 2030 [1]. This 43% reduction in ten years necessitates a comprehensive building renovation strategy and a rapid reconsideration of applicable heating technologies. Heat pumps offer a very efficient form of individual heat supply. On the other hand, concerns are being raised that power grids might not be able to serve the additional loads resulting from a high distribution of heat pumps and that only the gas grid can guarantee an affordable heat supply. The usage of green hydrogen for the heating sector is presented as the favorable option by the gas economy [2]. As a contribution to this ongoing discussion, the paper presents a comparison of costs for consumer and calculations of additional electricity grid loads for the city of Hamburg. The investment and operating costs for end consumers are extrapolated and compared for heat pumps, condensing boilers using natural gas and/or green hydrogen. In a second step, future heat pump scenarios are compared with the present situation to estimate possible grid overloads. The scenarios represent different refurbishment rates and a variation of district heating, decentralized renewable heating (i.e. wood pellets), and heat pumps. For evaluation purposes, the currently used power supply for direct power heating systems is assumed to be available for heat pumps.