This study presents three cost-optimal calculations. The overall aim is to provide a deeper analysis and to provide additional guidance on how to properly implement the cost-optimality methodology in Member States. Without proper guidance and lessons from exemplary case studies using realistic input data (reflecting the likely future development), there is a risk that the cost-optimal methodology may be implemented at suboptimal levels.

The economics of energy efficiency programmes have been subject to considerable academic debate lasting well over three decades now. In this paper, we contribute to this debate by reviewing the costs and benefits of a specific type of policy+ instrument that recently gained significant traction in Europe – Energy Efficiency Obligations - EEOs. Following the introduction of the EU Energy Efficiency Directive in 2012 the number of EEOs in Europe has grown from five schemes to now 16 EEOs in operation or planned across the EU.