Comparison of Long-Term Climate Protection Pathways (until 2050)

  • Project no. 2134
  • Duration 03/2009 - 12/2010

Based on findings from climate science, the EU and many other countries have declared their intention to work towards limiting the increase in average global temperature to below 2 °C compared to pre-industrial times. This will probably require industrialised countries to reduce their greenhouse gas emissions by 25 to 40 percent until 2020 and by 80 to 95 percent until 2050 compared to 1990 levels.

As our use of energy is responsible for most of the greenhouse gas emissions, there is no doubt that the global as well as the German energy system will have to undergo significant changes until the middle of the century. However, there is no consensus among scientists, politicians and the public in general about how exactly a future climate-friendly energy system will or should look like.

During the course of this research project several different plausible energy scenarios for Germany will be developed and subsequently evaluated based on a number of criteria. All scenarios will have in common an 85 percent reduction in energy-related CO2 emissions by 2050 (compared to 1990 emissions). The energy scenarios will be developed until 2050 as any climate protection analysis needs a long-term perspective. This time horizon also makes it possible to assess whether certain climate protection strategies that appear to be cost-effective in the short or medium term are also good choice for achieving cost-efficient climate protection in the long term.

On the demand side the scenarios mainly differ in regard to the extent that energy efficiency is improved. On the supply side two main developments are described: In one scenario ("structurally conservative scenario") fossil fuel power plants with carbon capture and sequestration (CCS) technology are assumed to become a viable option for CO2 abatement. In the other scenario ("structural change scenario") renewable energy technologies are the only mitigation option to significantly decarbonise electricity supply. In addition, several scenario variants are developed to take into account important uncertainties, e.g. fossil fuel prices, renewable energy potentials and the possible energy saving contribution of behavioural change.

The scenarios developed will be evaluated based on ecological criteria (e.g. amount of radioactive waste, amount of CO2 sequestered) and socio-economic criteria (e.g. effects on consumption and GDP, import dependency and the robustness of each scenario's climate protection measures) in order to come up with suggestions for policymakers. The project is carried out by the Wuppertal Institute for Climate, Environment and Energy (WI) in collaboration with the Potsdam Institute for Climate Impact Research (PIK). Both institutes' modelling approaches are combined to develop the different scenarios, i. e. the hybrid model REMIND-D (PIK) with its coupled macroeconomic growth and energy system model is linked to the sophisticated bottom-up energy demand model DEESY (WI).