Is "green hydrogen" the future? This Minnesota gas company thinks so.

A Minnesota gas utility says it is successfully blending "green" hydrogen into its pipeline system in one of the first such tests in the country.

Since last spring, CenterPoint Energy customers near downtown Minneapolis have been burning some hydrogen in addition to the usual methane gas mix in their stoves and ovens.

The utility completed a $2.5 million hydrogen pilot plant last year and began injecting the carbon-free fuel into its system in small quantities in June. Hydrogen is no more than 5% of the overall mixture at any time.

"The good news is that this facility has integrated well with our distribution system," CenterPoint spokesperson Ross Corson said of the facility's first few months of operation.

The pilot project is a chance for the utility to resolve operational issues. It has already made several adjustments, including changes to the water circulation system and the way it removes moisture before injecting the gas into its pipes.

But even a technical success for the project is unlikely to resolve broader questions in Minnesota and beyond about hydrogen's role in a clean energy economy. Some climate experts and advocates have argued that blending hydrogen into the natural gas system is an inefficient and costly climate solution compared to switching to electric appliances, and that hydrogen should be reserved for industrial and domestic uses. other hard-to-decarbonize sectors.

Related: Toyota is converting some classic cars to run on electricity and hydrogen

Most hydrogen today is produced from a chemical process involving fossil fuels that releases significant carbon emissions. "Green" hydrogen is produced by using electricity to split water molecules into hydrogen and oxygen. If done with renewable electricity, it can be a zero-emission fuel source.

"The hydrogen color wheel is complex and a bit overwhelming, but green hydrogen, as long as it's generated from renewable electricity, is the gold standard," said Joe Dammel, St. Paul's Clean Energy Buildings Program Manager. advocacy group Fresh Energy, which publishes Energy News Network.

The small CenterPoint plant sits on the site of a former coal gasification plant that began operation when CenterPoint was called the Minneapolis Gas Light Company. The company chose the site because of its central location in its pipeline network and the availability of space. The land now houses the Green Hydrogen Center and parking for workers taking classes across the street at a CenterPoint training facility.

John Heer, director of gas storage and supply planning, oversees the installation. Making green hydrogen isn't a huge technical feat and involves electrolysis, Heer said.

City water is purified before being sent to a 1 megawatt electrolyser that processes two gallons per minute. The facility disperses oxygen through fans outside the plant. “We learn by doing,” Heer said. "We need to know how it works before we can scale it into a larger installation."

The facility obtains electricity from the Xcel Energy grid and offsets its electricity consumption with renewable wind energy credits, also purchased from Xcel. Critics have questioned whether hydrogen facilities that use renewable energy indirectly through offsets should be called "green".

Part of the pilot project is to determine how hydrogen changes the characteristics of natural gas in pipelines. Hydrogen is less dense than methane and carries only about a third of the energy per cubic foot. The molecules are the smallest in the universe and can aggravate cracks in pipelines and cause embrittlement, increasing the chances of leaks and explosions above certain concentrations, according to the National Renewable Energy Laboratory.

In July, a study by the California Public Utilities Commission found that 5% mixtures of hydrogen and natural gas are safe, but going beyond that amount may require modifications to stoves and heaters. water heater. Also, because green hydrogen contains less energy, more of it would be needed to replace natural gas, according to the report.

Even if produced from entirely renewable sources, hydrogen is unlikely to replace natural gas...