Patent portfolios of European wind industry: New insights using citation categories

• Cooperative Patent Classification is better than International Patent Classification in retrieving wind industry patents.
• We introduce two measures that can indicate hindrance and encroachment of a firm's patent portfolio relative to competitors.
• Results indicate that there is substantial overlap among the patent portfolios of top wind power firms.

This study explores the use of citation categories assigned by patent examiners to study overlap of patent portfolios among top wind power firms. Cooperative Patent Classification (CPC) is used to obtain a sample of wind industry patents. CPC is shown to be better than the International Patent Classification for identifying patents relevant to the wind power industry. Results show high inter-firm citation among the top wind industry players that can suggest concentration of innovation. The results can be useful for patent analysts, technology managers and policy makers.