Energy services provided by energy suppliers have been identified as important in supporting sustainable development. However, the energy suppliers struggle in developing services that support the end-users energy efficiency, due to e.g. limited customer engagement and competition from actors with expertise in e.g. data analytics. The purpose of this paper is to investigate challenges faced by energy suppliers when developing services aimed at improving the end-users’ energy efficiency. A single case-study identifies challenges for energy service development that relate to capabilities and organisation, respectively.