Nel Hydrogen US is the U.S. operating subsidiary of Nel ASA responsible for the manufacturing of proton exchange membrane (PEM) electrolyser stacks and systems. It operates a dedicated production facility in Wallingford, Connecticut, which was significantly expanded and automated in 2024 to reach an annual capacity of 500 MW.
The company produces high-purity hydrogen generation equipment used across industrial, energy, and defense sectors. Notable applications include supplying PEM stacks for oxygen generation systems on U.S. Navy submarines through long-term contracts with Collins Aerospace, as well as electrolysers for public utilities and steel production facilities in the United States.
As a wholly owned subsidiary of the Oslo-listed Nel ASA, Nel Hydrogen US integrates with the parent company's global portfolio that also includes alkaline electrolyser manufacturing in Norway. Nel ASA, with origins dating back to 1927, is recognized as a leading provider of electrolyser technology with thousands of installations worldwide.
The Wallingford operations trace their roots to Proton Energy Systems, founded in 1996 and acquired by Nel in 2017, bringing specialized PEM expertise to the group. This positions Nel Hydrogen US as a key contributor to the advancement of reliable and scalable PEM electrolysis technology essential for the green hydrogen economy.
Also known as Proton Energy Systems, Inc. and Proton OnSite.
PEM stacks for oxygen generation in US Navy submarine life-support; built in Wallingford, Connecticut; deliveries across 2027–2028.
