The European Commission’s scenarios supporting a long-term climate strategy are deficient on energy efficiency, according to our review. Choices and assumptions on energy efficiency investments, technologies and solutions are made, but are not explained and justified. Furthermore, they build on a pessimistic future policy outlook. The 2050 energy savings of up to 43% achieved in the Commission’s scenarios are well below the cost-effective potentials of 51%, which can reach up to 67% with societal trends, according to a new Fraunhofer ISI research, commissioned by the Coalition for Energy Savings.