Inventor networks in renewable energies: The influence of the policy mix in Germany

Technological change and gains in efficiency of renewable power generation technologies are to a large extent driven by governmental support. Various policy instruments that can broadly be categorized as technology push, demand pull or systemic constitute part of the policy mix for renewable energies. Our goal is to gain insights into the influence of this policy mix on the intensity and organization of inventive activities for wind power and photovoltaics in Germany since the 1980s. We examine the effect of different instruments on the size and structure of co-inventor networks based on patent data. Our results indicate notable differences between the technologies: the network size for wind power is driven by technology push and systemic instruments, while in photovoltaics, demand pull is decisive for network growth. By and large, the instruments complement each other and form a consistent mix of policy instruments. The structure of the networks is driven by demand pull for both technologies. Systemic instruments increase interaction, especially in the wind power network, and are complementary to demand pull in fostering collaboration.