A study by the Riksbank and the Royal Institute of Technology has analysed the potential climate impact of a central bank digital currency (CBDC), such as the Swedish e-krona. The study focuses on the electricity consumption of different system designs and compares the energy use of a potential e-krona with existing payment systems, such as card payments. The results show that a centralised design is the most energy-efficient, although the climate impact is affected by transaction volumes, server location and energy sources. The report recommends further research on technical solutions to evaluate the long-term climate impact of an e-krona.