Hydrogen Is One Answer to Climate Change. Getting It Is the Hard Part.

Hydrogen is one of the most plentiful elements in the universe, but producing it in a way that is emission-free is costly. Pioneering companies are working to change that.

SHEFFIELD, England — Rachel Smith has lived through green hydrogen’s bumpy journey from scientists’ dream to an industry that may be on the verge of a commercial breakthrough. An engineer, she started out two decades ago working in a converted barn on early devices for making the clean-burning gas. Now she is part of a team racing to build giant machines that will use electricity to separate hydrogen from water for major companies like Royal Dutch Shell and Orsted, the Danish offshore wind developer. “We have gone through those toddler years,” said Ms. Smith, an executive director at ITM Power, which is run out of an expansive new factory in Sheffield, a faded center for steel mills and coal mining. “We are playing in the grown-up world rather than in research labs.”