A new patent insight report on electrolysers for hydrogen production

A new patent insight report based on a joint study by the EPO and the International Renewable Energy Agency (IRENA) reveals the patent filing trends in the exciting field of electrolysers for hydrogen production using water. Since 2005, patent filings covering technologies for hydrogen production through electrolysis of water have grown on average by 18% each year. The report looks into a number of essential features and characteristics which inventors are working on to make electrolysers cheaper and more efficient.

These technical developments are crucial for combatting climate change. As a low-carbon method of producing energy, hydrogen produced via water electrolysis is expected to be at the heart of the transition to more sustainable energy production. In order to achieve this, innovation is needed to make the method as affordable and efficient as possible. Below are some examples of the joint study's important and promising trends primarily based on data found in Espacenet, PATSTAT and the European Patent Register.


Figure 1: 2005-2020 trend of hydrogen production patent families based on production process

As can be seen in the figure above, in 2016 the number of international patent families for water electrolysis technologies surpassed the number of patents related to producing hydrogen from fossil sources (e.g. solid or liquid coal and oil-based hydrogen sources). International patent families are patents that have more than one country in the list of publications, assignees, inventors or first priority countries.


Figure 2: 2005-2020 trend of international patent families based on electrocatalyst material

Similarly, in 2018 inventions for electrocatalysts based on cheaper materials (such as non-noble metals, alloys or ceramics) surpassed the number of inventions using more traditional but expensive electrocatalysts based on noble metals, confirming the drive for cheaper and more environmentally-friendly alternatives. This patent insight report is supported by an Excel workbook containing all the Espacenet-based search strategies as well as the aggregated data used in the report.

For the purpose of the analysis we developed search strategies that would match a predefined structure of important electrolyser characteristics as outlined in the scheme.


Figure 3: Summary of technology and sub technology areas analysed in the report (click to enlarge)

The identification of relevant inventions in our patent data is based on expert searches by an EPO examiner. For example: IPC/CPC code C25B11 is generally used to classify electrodes. But in order to distinguish between the different electrocatalyst materials, we needed to include or exclude additional classifications codes. To exclude, for example, the "noble metals", we had to remove patents classified with C25B11/081 (the element being a noble metal) as well as C25B11/097 (comprising two or more noble metals) and C25B11/093 (at least one noble metal). We, however, observed that this classification‑based approach was insufficient so we further narrowed down the sample by excluding patents with references in the claims to platinum, gold, silver, ruthenium, iridium, rhodium, palladium or rhenium to obtain a specific list of noble-metal-free inventions.

Through its environmental policy, the Office is committed to the United Nations Sustainable Development Goals (SDG). The EPO-IRENA study is focused on renewable energy and therefore contributes to UN SDG 7 (Ensure access to affordable, reliable, sustainable and modern energy for all).

Further reading

Patent insight reports

Full report - Innovation trends for electrolysers in hydrogen production

Excel workbook with search strategies (XLS, 72 MB)

Interactive data (Tableau workbook)