In a new article "Knowledge spillovers from renewable energy technologies: Lessons from patent citations" published in the journal Environmental Innovation and Societal Transitions, Joëlle Noailly and her co-author Victoria Shestalova unravel which technological fields benefit from knowledge developed in storage, solar, wind, marine, hydropower, geothermal, waste and biomass energy technologies.

 

Using citation data of patents in renewable technologies filed at 18 European patent offices over the 1978–2006 period, the authors examine the importance of knowledge flows within the same specific technological field (intra-technology spillovers), to other technologies in the field of power-generation (inter-technology spillovers), and to technologies unrelated to power-generation (external-technology spillovers). 

 

The results show significant differences across various technologies. First, inventions in solar and storage energy tend to be particularly important: these patents receive a large number of citations and find applications in a large set of diverse fields (such as semiconductors, thermal processes and  civil engineering)– combining two characteristics of highly valuable innovations and therefore warranting larger policy support.

 

Second, for wind technologies, once the stock of wind inventions is large enough, specific innovation subsidies may no longer be needed since the technological field will benefit from large intra-technology spillovers, ensuring that these technologies will continue to develop fast. 

 

Finally, the results show that the knowledge from waste and biomass energy mainly flows to other fossil-fuel technological fields. Hence, policy support for waste and biomass may contribute to further increases the fossil-fuel knowledge base.