SK Corp, the holding company of SK Group, has made a strategic investment in Monolith, a US company that has developed a plasma-based process to produce “cyan” hydrogen—between green (via electrolysis using renewable energy) and blue (conversion of methane accompanied by CO2 capture and storage).

As a strategic partner and leading investor, SK also secured a seat on the Monolith Board of Directors. Nextera, the largest power generation and renewable energy development company in the United States, also participated in the round.

Monolith’s cyan hydrogen is produced by injecting natural gas containing methane (CH4) as a main component into a high-temperature reactor and decomposing it into hydrogen (H2) and solid carbon (C). The solid carbon is processed into carbon black, the main component of tires, and sold. Because carbon dioxide is not generated during the production process, it is classified as a clean hydrogen process along with blue hydrogen and green hydrogen.

The competitiveness of cyan hydrogen is that it has both the economic feasibility of blue hydrogen and the eco-friendliness of green hydrogen. Because carbon dioxide is not generated during the production process, it does not have to go through the carbon capture and storage (CCS) process essential for blue hydrogen production, and it can be produced with less electricity than green hydrogen.

SK, which is pursuing a strategy to foster the hydrogen business in various ways—such as diversifying hydrogen production methods, expanding demand development, and preoccupying the global market—is adding the cyan hydrogen portfolio to the hydrogen business value chain. SK’s hydrogen business roadmap aims to establish a clean hydrogen production system with a scale of 280,000 tons by 2025.

Monolith was founded in 2012, and completed the world’s first cyan hydrogen mass-production plant in June 2020. SK says Monolith is the only company with cyan hydrogen process technology that has entered the commercialization stage.

SK has also secured about 10% of a stake in US Plug Power, a global hydrogen leader, and became the largest shareholder.