Closing the ambition gap: Germany's energy transition in line with a 1.5°C carbon budget

To limit global warming to 1.5∘C, rapid and significant reductions in greenhouse gas emissions are essential. However, there is a lack of analyses considering transition pathways using sector-coupled energy system models that limit national emissions to a 1.5∘C per capita carbon budget. This paper uses the REMod energy system model to derive a possible transition pathway within this budget. The model results show that immediate action in all aspects of the energy system is required, together with fundamental changes in energy policy and society, in order to stay within the remaining carbon budget. A crisis response that induces substantial and immediate demand reduction through societal behaviour change is essential. Furthermore, annual capacity additions of renewable energy sources such as wind and solar need to increase at rates four to seven times higher than historical maxima and the direct electrification of all sectors should be accelerated by replacing technologies even before they reach the end of their life (e.g. gas boilers and internal combustion engine vehicles).