SK Group closes $1.6B investment in Plug Power to advance hydrogen strategy; new Hydrogen Business Development Center SK Group, South Korea’s largest energy provider and third-largest conglomerate, announced the close of a $1.6-billion investment in and strategic partnership with Plug Power Inc., a leading provider of hydrogen fuel cell and fueling solutions enabling e-mobility. (Earlier post.) The partnership is part of a long-term, multi-billion dollar plan by SK to help lead the global transition to a hydrogen economy and make meaningful progress toward a more sustainable energy system. Recognizing the importance of hydrogen as a clean alternative to traditional energy sources, SK Group has heightened its focus on building the infrastructure and developing the technology to make hydrogen energy a reality for global markets.