A highly efficient use of energy is thus fundamental to limit GHG emissions. Yet, energy efficiency receives much less attention than the decarbonization of the energy supply. This study indicates that scenarios with higher energy efficiency mostly show lower abatement costs. This was the result of evaluating the large number of existing scenarios that comply with the internationally agreed 2°C target until 2050. The societal costs of decarbonization in these scenarios vary strongly and a detailed assessment of the potential cost reductions due to EE is lacking. In order to close this gap...