This preface introduces the special section on the assessment of wind and solar in global low-carbon energy scenarios. The special section documents the results of a coordinated research effort to improve the representation of variable renewable energies (VRE), including wind and solar power, in Integrated Assessment Models (IAM) and presents an overview of the results obtained in the underlying coordinated model inter-comparison exercise.
Using the improved modeling approaches developed during the ADVANCE project, we were able to provide a more robust picture of the potential role of renewables for future low-carbon electricity supply. The following five insights are of particular interest and policy relevance:
- Wind and solar technologies are likely to contribute substantially to the low-carbon transformation of the power sector in climate change mitigation scenarios. They combine for more than half of the electricity supply in 2 °C-consistent policy scenarios in the long-term.
- Carbon pricing and the availability/social acceptance of nonrenewable low-carbon power sources are the most important determinants of the role of VRE. Carbon prices in line with the 2 °C limit will make wind and solar technologies immediately competitive in many world regions. If nuclear power or carbon capture and storage are removed from the portfolio of mitigation options, a much larger portion of electricity needs to be supplied from VRE.
- The methodological improvements of the IAMs, in particular with regard to the representation of integration challenges, have resulted in a more accurate representation and simultaneously indicate a greater potential role of VRE to contribute to mitigation. This is largely due to the fact that previous, simpler modeling approaches overemphasized integration challenges, and did not account for key integration options such as storage or large-area pooling through improved grid interconnection (Pietzcker et al., 2017-in this issue). The shares of VRE in electricity supply in the 2 °C-consistent scenarios from all six models are above the median of corresponding scenarios from the IPCC AR5 scenario data base.
- Our multi-dimensional sensitivity study shows that VRE integration challenges are of similar importance as direct technology costs in determining future VRE deployment levels.
- In large parts of the world, the availability of renewable energy resources is not a limiting factor. Our results suggest that in the global aggregate, VRE deployment levels are relatively robust to assumptions on the magnitude of the resource potential.
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