Support cost efficiency of renewable energy auctions - An empirical design analysis

Renewable energy sources (RES) are a key technology for electricity generation to mitigate climate change and reduce import dependency. Therefore, policymakers in the European Union (EU) and other countries worldwide have implemented support instruments to increase the RES share in their energy systems. Policymakers strive to achieve certain policy objectives with their support instruments, most notably effectiveness, i.e., achieving a specific RES target, and support cost efficiency, i.e., minimising the support expenditures for achieving the target. These policy objectives can interact with and even contradict each other. If support cost efficiency is pursued, auctions are theoretically a well-suited instrument. Thus, it is not surprising that in recent years an increasing number of countries have implemented auctions, making them the predominant RES support instrument in the EU and worldwide. Nevertheless, whether countries can reach their policy objectives depends not only on the choice of the instrument but also on its concrete design. Given this context, this dissertation investigates the following overarching research question: How can support cost efficiency be achieved in renewable energy auctions along with other policy objectives? Five distinct research questions were answered in this dissertation to ad-dress the overarching question. Overall, this dissertation contributes to the existing literature with its empirical research on the support cost efficiency of RES auctions. Using qualitative methods, econometric models, and techno-economic modelling, this dissertation was able to provide new insights into: 1) the relation of support cost efficiency with other policy objectives and 2) the (statistical) effects of auction design elements and their specific implementation on support cost efficiency. These findings are especially valuable for policymakers designing RES auctions and researchers active in the field of RES support schemes.