Inventive Concentration: An Analysis of Fuel Cell Patents

Alan Pilkington, Catherine Liston-Heyes

Research output: Contribution to journalArticlepeer-review


Patterns of ‘inventive concentration’ in green technologies are measured and analysed using patent data on fuel cells — potentially one of the most important ‘green’ technologies. Six measures are described and tested: the coefficient of variation; the Herfindhal index; the 4-firm and 8-firm concentration ratios; the Lotka coefficient; and the Gini coefficient. Initially, the analysis focuses on US firms but becomes comparative to include Japan, Germany, UK, France, Canada, Australia, Switzerland, Italy, Sweden, Netherlands, and Israel. This allows the level of agreement among the various measures to be assessed and the nations to be ranked in terms of the concentration of their fuel cell patent production. This sector is concentrated in all 12 nations with Canada (Sweden) exhibiting high (low) levels of concentration across all measures. These are discussed in the context of recently published international ratings of national innovative capacity along with directions for future research. %Z article %U
Original languageEnglish
Pages (from-to)14-25
JournalScience and Public Policy
Issue number1
Publication statusPublished - 2004


  • best-practice, bibliometrics, bibtex-import, cell, electric-vehicle, fuel, global, innovation, alignment, local, management, manufacturing, patent, portfolio, strategies, technology

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