Dynamic structures of knowledge production: Citation rates in hydrogen technologies

February 2025

This paper proposes a new way of looking at how quickly technologies improve. When new inventions are protected by patents, they cite older patents. The speed of these citations tells us how quickly a technology is improving. The faster the citations, the faster the improvement.

This study looks at all the patents related to hydrogen technology and finds that the speed of citations varies across different parts of this technology, like production, storage, and distribution. Interestingly, patents related to hydrogen distribution are cited much slower than others. This means that the distribution of hydrogen is likely to be the most expensive part of using hydrogen as a fuel. The paper also finds that the more central a patent is in the network of citations, the faster it gets cited. This means that important, foundational patents drive the speed of technological improvement.

These findings have implications for businesses and policymakers because they help identify which parts of hydrogen technology are improving quickly and which are lagging behind. This information can help guide investments and policy decisions to support the growth of a hydrogen economy.