SK Inc., the holdings firm of SK Group, said Thursday that it has acquired a stake in Monolith, the world’s first company to have successfully mass-produced “turquoise hydrogen.”

The strategic investment was made by a consortium led by SK Inc., of which NextEra, a leading clean energy company in the US, was also a participant. SK did not disclose the investment amount, but industry sources said it would likely be in the range of tens of millions of dollars.

Although hydrogen itself is colorless, the industry has come up with color descriptors to differentiate its source and methods of production. Blue hydrogen extracts hydrogen from natural gas and captures carbon emitted from the process. Green hydrogen breaks water into hydrogen and oxygen with electricity generated by renewable energy. Turquoise hydrogen is the combination of the two, as it uses natural gas as a feedstock and heat produced with electricity. Some classify turquoise hydrogen as green hydrogen as it doesn't directly emit carbon.

“Compared to blue hydrogen, turquoise hydrogen doesn’t emit carbon when it’s produced and therefore doesn’t require carbon capture and storage process,” an SK official said. “Also, turquoise hydrogen needs less electricity than green hydrogen, so it has strategic value as a temporary alternative before the industry shifts completely to green hydrogen from blue hydrogen.”

The investment is expected to accelerate SK’s hydrogen roadmap, which revolves around producing 280,000 metric tons of clean hydrogen by 2025.

Based in Nebraska, Monolith was founded in 2012, and has source technologies in producing high-purity turquoise hydrogen and solid carbon by injecting natural gas into its independently developed reactor and breaking the gas with heat.

In June last year, Monolith completed the world’s first turquoise hydrogen plant for mass production, and is evaluated as the world’s only company with commercial-level source technologies.

By Kim Byung-wook (kbw@heraldcorp.com)