Mitsui joins Aker Horizons as long-term strategic investor in Mainstream Renewable Power to accelerate growth




24 March 2022



  • Mitsui & Co., Ltd. invests EUR €575 million in Mainstream Renewable Power to accelerate growth of Mainstream’s renewable energy portfolio globally, including across the Americas, Africa and Asia-Pacific
  • Mainstream will issue new common shares, giving Mitsui a 27.5 percent ownership interest
  • Mitsui to strengthen Mainstream’s transformation into Renewable Energy Major through complementary geographic footprint, global customer network and industrial capabilities
    Mainstream Renewable Power, the global renewable energy company, is pleased to announce that Mitsui & Co., Ltd. has agreed to invest EUR €575 million in Mainstream in the form of new common shares, corresponding to a 27.5 percent equity stake in the Company.


Mitsui will take a long-term active role in the growth of the Company, alongside Aker Horizons, which will own 54.4 percent of Mainstream following the transaction.

This transaction values Mainstream at approximately EUR €2.1 billion on a 100 percent basis.

Delivering significant operation progress

A wind turbine from Hornsea wind farm being constructed

Developed by Mainstream, the UK’s Hornsea zone is the largest operating offshore wind farm in the world. Image: Ørsted

Mainstream is a pure-play renewable energy company with a 14-year track record in developing, building and operating wind and solar generation assets across global markets, including in Latin America, Africa, and Asia-Pacific.

It is one of the most successful developers of gigawatt-scale renewables platforms across onshore wind, offshore wind, and solar power generation, having successfully delivered 6.5 GW of assets to financial close-ready including the Hornsea zone, the world’s largest offshore wind farm in operation today.

Since Aker Horizons announced the acquisition of a 75 percent stake in Mainstream in January 2021, the company has delivered material operational progress, including:

  • Advancing the construction of its wholly owned 1.4 GW Andes Renovables wind and solar generation platform in Chile which is on track to be fully operational next year
  • Increasing its global portfolio by 5.2 GW, bringing it to 16.6 GW
  • Obtaining preferred bidder status for 1.27 GW of wind and solar projects in South Africa
  • Launching the 1 GW Nazca Renovables platform in Chile, including the signing of a private PPA with a strategic partner
  • Securing an investment decision from regional authorities for the first 200 MW of the 1.4 GW Phu Cuong Soc Trang offshore wind project in Vietnam
  • Acquiring an initial 50 percent ownership stake in an 800 MW floating offshore wind project in Japan, alongside with Aker Offshore Wind
  • Successfully completing the planned divestment of Chilean power producer Aela Energia, Chile’s largest independent producer of renewable energy, for USD 686 million, and progressing the divestment of one of Africa’s largest independent power producers, Lekela Power, with targeted completion by the end of this year


Group CEO Mary Quaney

Group CEO Mary Quaney says investment will reinforce Mainstream’s leadership position in the global race to net zero

Mary Quaney, Group Chief Executive of Mainstream Renewable Power, said: “There has never been a more critical time in the history of our planet to accelerate the global transition to renewable energy.

“Today’s transformational announcement reinforces Mainstream’s leadership position in the global race to net zero, as well as enabling nations to rapidly reduce their dependence on oil and gas imports through the large-scale deployment of renewables.

“We are delighted to welcome Mitsui as our new strategic partner alongside Aker Horizons. Together we are fully focused on expediting our ambitious growth plans and leveraging our collective expertise and resources to transform Mainstream into a global renewable energy major this decade.”

Kristian Røkke, Chief Executive of Aker Horizons and Chairman of Mainstream, said: “Mitsui is the perfect partner for Mainstream to accelerate the company’s growth to become a renewable energy major.

“I have known Mitsui for many years and am certain that their rich industrial heritage, global presence and like-minded approach to sustainability will bring substantial value to Mainstream. We see Mainstream as an integral part of Aker Horizons’ plans to develop mega-scale green industrial hubs, drawing on synergies between Mitsui, the Aker Horizons portfolio and other strategic partners.”

Mitsui COO Kazumasa Nakai, left, and Kristian Røkke, CEO of Aker Horizons, right

Mitsui COO Kazumasa Nakai, left, and Kristian Røkke, CEO of Aker Horizons, believe the Japanese company’s global business networks will bring substantial value to Mainstream

Kazumasa Nakai, Chief Operating Officer of Mitsui, said: “We are delighted to participate in Mainstream jointly with Aker Horizons to boost growth and expansion of development and construction/operation activities of Mainstream, by leveraging our global business networks with customers across industries and its wide-ranged industrial capabilities, including deep expertise in the global power sector.

“We are convinced that the participation in Mainstream will further strengthen the strategic partnership between the Aker group and Mitsui, driving forward our renewable energy transition and greenhouse gas reduction in response to global climate change.”


Mitsui, Aker Horizons and Mainstream aim to promote and develop strong business clusters in the Renewable Energy space, building on years of successful cooperation between Mitsui and the Aker group.

Mitsui’s investment in Mainstream will further strengthen the strategic partnership between the two industrial groups, paving the way for collaborations in new business areas such as energy trading, energy management, battery storage, as well as green hydrogen and ammonia.

Mitsui aims to develop business clusters of scale within renewable energy assets by leveraging integrated functions of its various business units.


The transaction will be completed as a private placement of common shares in Aker Mainstream Renewables AS, the holding company of Mainstream Renewable Power, towards Mitsui, raising EUR €575 million in gross proceeds to the Company. Following the transaction, Mitsui will hold a 27.5 percent share in Mainstream, Aker Horizons will hold 54.4 percent and Mainstream’s founder, Eddie O’Connor, along with Irish retail investors hold the remaining 18.1 percent. Closing of the transaction is expected in April 2022.

Mitsui, Aker Horizons and Mainstream intend to continue developing Mainstream towards an initial public offering, although the transaction secures flexibility with regards to the timing of future funding of Mainstream.

DNB Markets, a part of DNB Bank ASA, has acted as financial advisor and Advokatfirmaet BAHR AS has acted as legal advisor to Mainstream and Aker Horizons in connection with the transaction.


Mitsui & Co., Ltd. is one of the leading Japanese general trading and investment firms, established in 1947, with global presence in the various business fields and 63 countries/regions with approximately 45,000 employees. Mitsui’s core strategic aim is to pursue sustainable growth, and through its business activities contribute to the development of countries and regions around the world while addressing climate change and other global issues. As part of this, Mitsui has set a target to reduce GHG impact by 2030 to half of what it was in 2020 and achieve net-zero emissions by 2050. Mitsui currently has 65 power assets in 22 countries, with gross capacity of 39.6GW and net capacity (Mitsui’s share) of 10.8GW.


Aker Horizons ASA is a planet-positive investment company dedicated to developing companies within renewable energy and other technologies that reduce emissions or promote sustainable living. The company is listed on the Oslo Stock Exchange and majority-owned by Aker ASA. Aker Horizons’ investment portfolio includes holdings in Aker Clean Hydrogen, Aker Offshore Wind, Aker Carbon Capture and Mainstream Renewable Power. View the corporate website here.


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