OSLO, March 24 (Reuters) - Japanese trading house Mitsui has agreed to invest 575 million euros ($631 million) for a 27.5% stake in Mainstream Renewable Power, a company controlled by Norway's Aker Horizons, the companies said on Thursday.
The transaction, valuing Mainstream at 2.1 billion euros, leaves Aker Horizons' holding at 54.4%.
"Mitsui, Aker Horizons and Mainstream will continue developing Mainstream towards an initial public offering," the three companies said in a joint statement.
Mitsui's investment and global business network will help Mainstream to speed expansion of its portfolio of wind and solar energy in the Americas, Africa, Asia-Pacific and Europe, they added.
Mainstream will also expand in battery storage, power trading, green ammonia and green hydrogen production, the companies said.
"Mitsui is the perfect partner for Mainstream to accelerate the company's growth to become a renewable energy major," said Aker Horizons CEO and Mainstream Chairman Kristian Roekke.
Aker Horizons bought a 75% stake in Mainstream at the start of 2021, valuing the business at 900 million euros.
($1 = 0.9107 euros)
Reporting by Terje Solsvik Editing by David Goodman