Requirements and options to comply with the obligation to use renewable energies in existing buildings enacted in the Hamburg Climate Protection Act (HmbKliSchG) and the resulting costs for building owners

With the Act on the Re-enactment of the Hamburg Climate Protection Act of 20.02.2020, the city of Hamburg introduces an obligation to use renewable energies in the heat supply for existing buildings. Specifically, building owners will be required to use renewable energy to meet at least 15 % of their annual heat demand when replacing or retrofitting a heating system. The law authorizes the Hamburg Senate to determine the detailed form of the obligation to use renewable energies in a legal ordinance. The study serves as scientific support for the preparation of the legal ordinance. For this purpose, different RE technology variants (primary obligation-fulfilling RE measures, substitute measures and combination options) are analyzed for different city-specific building types and renovation levels, with which the use obligation can be fulfilled and which make sense from an energy-economic and social perspective.