Beyond innovation and deployment: Modeling the impact of technology-push and demand-pull policies in Germany's solar policy mix

Governments around the world try to accelerate sociotechnical change toward sustainability by introducing policy mixes that combine technology-push and demand-pull instruments. Beyond innovation and deployment, other objectives, such as domestic job and industry creation, are usually part of these policy mixes. However, little is known about how policy mixes should be designed and interactions between policy instruments considered when governments try to achieve multiple objectives simultaneously. We address these questions using an agent-based model of the sociotechnical system for solar photovoltaics in Germany that simulates technology adoption, industry dynamics, international spillovers and trade. By changing public spending on research and development and the solar feed-in tariff, forty-five variations of the historical policy mix in Germany are systematically evaluated. The results show that a narrow focus on innovation and deployment outcomes by academic researchers can lead to recommendations for the design of policy mixes that compromise key dimensions of sociotechnical change, such as job creation. Moreover, the simulations reveal that, because of path-dependent interactions between policy instruments, minor changes in the design of policy instruments can lead to vastly different policy outcomes. These findings have important implications for the literature on policy mixes, technology-push and demand-pull instruments, and sociotechnical transitions.