Decarbonising existing buildings with heat pumps – Early evidence and policy analysis for Switzerland

In order to overcome the problem that oil and gas boilers in existing buildings are typically replaced again by fossil fuel boilers, leading cantons in Switzerland have started to implement more targeted decarbonisation policies. The objective of the present paper is to critically discuss the experience made with policy measures for the decarbonisation of building-related heating systems in these cantons. For this purpose, semi-structured interviews were conducted as primary method. Early evidence indicates that the policies are effective by ensuring the transition to renewable heating technologies (primarily heat pumps). The implemented policy packages include coercive elements (mandatory renewable energy shares), subsidies as well as information and communication measures, resulting in a quasi-ban of fossil fuel boilers. Avoiding outright bans of fossil fuel use seems both effective to increase acceptance among building owners and reasonable to account for particularly demanding cases of boiler replacement (for which there is no technically or financially viable, fully renewable solution). Considering the very low carbon footprint of its electricity supply, Switzerland is a particularly convincing case for the transition from fossil fuel boilers to electric heat pumps. This is shown by means of an analysis of the CO 2 emissions of heat pumps in comparison to gas and oil boilers across several European countries. We then compare the levelised cost of heat pumps for different subsidy levels. For a typical subsidy for the heat pump (equivalent to 11% of the investment cost), its levelised cost remains in an acceptable range compared to a gas boiler (7% more expensive). A sensitivity analysis shows the importance of high gas to electricity price ratios for financial viability. Evidence from leading cantons in Switzerland indicates that the chosen policy measures are effective, affordable and accepted and that they can be recommended to other countries.