South Korea’s largest energy company SK Innovation said Thursday it has invested an additional $50 million in Amogy, a US developer of ammonia-based full-cell systems, as part of efforts to expand its presence in sustainable fuel markets.

SK Innovation took part in the latest $139 million Series B-1 funding round for Amogy. Series B-1 refers to the stage of full-fledged business development among the stages of startup investment. This follows SK Innovation's initial $30 million investment in the Brooklyn-based startup in July last year.

Other investors in the latest funding included Singapore's sovereign wealth fund Temasek, a venture unit of Saudi Arabia's Aramco, Japan's Mitsui O.S.K. Lines Ltd, British venture capital firm AP Ventures and Korea Zinc.

Established in 2020, Amogy has developed a fuel cell system that directly turns liquid ammonia into hydrogen while on board, without carbon emissions. Having an energy density about three times greater than compressed hydrogen, liquid ammonia is cost-effective to store and transport. Through the on-board cracking of ammonia, hydrogen is extracted and sent into the fuel cell platform to power the vehicle.

SK Innovation has expanded the scope of cooperation related to ammonia-based hydrogen fuel cells, including business development and commercialization within Asia and Oceania, where demand for clean energy is expected to grow.

Amogy is pursuing carbon reduction in the transportation sector, using ammonia to drive a 5-kilowatt drone in 2021 and a 100-kilowatt tractor last year. The company successfully test-drove a class 8 semitruck running on its ammonia-based fuel cell system in January this year.

“SK Innovation and Amogy both agree on ammonia's role in providing clean energy without carbon emissions, and will continue to make efforts to expand related R&D and markets," said SK Innovation CEO Kim Jun.