Offshore Wind

A global frontrunner in offshore wind

Mainstream is a leading developer of offshore wind at scale globally. We have a diverse portfolio across fixed and floating wind where we leverage our development track record and industrialization capabilities – all while working closely and collaboratively with our stakeholders, partners and other users of the ocean.

We are currently bringing forward multi-gigawatt scale developments of offshore wind assets in markets including Ireland, Norway, South Korea, Sweden, the UK, Vietnam and Australia.

Mainstream’s track record includes developing and consenting several major UK offshore wind farms, including the world’s largest offshore wind farm in operation at Hornsea, off the coast of England.

As part of the Aker group, we benefit from decades of offshore energy development experience. Aker has been instrumental in the design and deployment of more than half of all semisubmersible floating offshore installations in the world. Our combination with Aker Offshore Wind has brought early mover positioning in floating wind.

Our Expertise

100+

Colleagues dedicated to offshore wind

2.8GW

(net) currently in development

40+

Memberships and leadership positions in offshore wind/industry associations

What distinguishes our offshore wind capabilities

Our strengths in offshore wind lie in our heritage and track record, coupled with our early mover position in markets and technology.

To accelerate offshore wind development, we need to leverage innovation – through technology, digitalisation and new collaboration models – to create a sustainable and flourishing industry.

Tove Røskaft - Head of Offshore Wind

Why Mainstream?

Proven deepwater wind technologies

Privileged access to proven floater design and offshore competence and technologies through ownership of Principle Power.

an aerial view of a floating offshore wind turbine base

Unparalleled offshore expertise

Leveraging Mainstream’s track record and building on the five decades of offshore and deepwater capabilities of the Aker companies to drive industrialisation and reduce costs.

Attractive project pipeline and partnerships

Early entrant position in attractive markets together with reputable consortium partners.

Solid focus on sustainability

Applying safety and sustainability as our competitive edge for offshore wind – throughout the project lifecycle.

Global footprint

A network of colleagues, offices and partners across the globe, giving us local insight to identify opportunities and deliver successfully.

Employing digitalization and innovation

Investing in next generation digitalisation solutions and participating in several research and innovation projects.

Offshore Leadership Team

Leadership Teams

Tove Røskaft

Head of Offshore Wind

Aidan Guinan

Chief Financial Officer, Offshore

Geir Olav Berg

Chief Technology Officer, Offshore

Sebastian Bringsværd

Senior Vice President Offshore Wind Norway

Sian Lloyd Rees

UK Managing Director

Holger Matthiesen

SVP Offshore Wind Europe and Global New Markets

Tove Røskaft

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Tove Røskaft

Head of Offshore Wind

Tove was appointed Head of Offshore Wind in 2022 and holds responsibility for the Offshore Wind center of excellence including development, projects, partnerships and technology.

Her appointment follows the integration of Aker Offshore Wind where she held the role of Chief Operating Officer. Tove joined Aker Offshore Wind in 2021 and has extensive global leadership experience. Her previous leadership experience at Aker includes roles such as Executive Vice President, Country Manager, Chief Communication Officer as well as leading large transformation projects in Aker Solutions.

In addition, she has held several other leadership roles within project management, manufacturing, and engineering. Through her over 25 years of experience in the energy industry, Ms. Røskaft has demonstrated the ability to inspire and motivate teams to deliver high performance and results.

Ms. Røskaft holds a M.Sc. in Marine Hydrodynamics from NTNU, the Norwegian University of Science and Technology.

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Aidan Guinan

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Aidan Guinan

Chief Financial Officer, Offshore

Aidan Guinan was appointed to the role of Chief Financial Officer, Offshore in March 2023 having led the merger and integration of Aker Offshore Wind into Mainstream in 2022.

Aidan has held several positions in Mainstream since he joined in 2014 most recently as Group Head of Investment Risk, Legal and Governance where he was responsible for reviewing new investment opportunities, assessing capital allocation and diversification of risk across the group. Prior to that Aidan was Group Head of Commercial supporting the regions in commercial and project finance transactions and Project Director where he led the disposal of Mainstream’s Neart na Gaoithe 450 MW offshore wind project to EDF in 2018.

Prior to joining Mainstream, Aidan worked for an Irish infrastructure developer where he led numerous M&A transactions and raised over US $1.25bn of project finance debt for two toll road PPP transactions in Ireland. Aidan trained with PwC Ireland and is a Fellow of the Institute of Chartered Accountants in Ireland.

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Geir Olav Berg

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Geir Olav Berg

Chief Technology Officer, Offshore

Geir Olav Berg is responsible for engineering and technology at the Mainstream Renewable Power Offshore Platform. He has over 30 years of experience in the offshore industry including Engineering Manager for Aker Solutions floating wind department. Geir Olav has held several management positions within subsea technology and project management at various Aker Solutions companies. Geir Olav has a passion for the opportunities presented renewables in combination with offshore technology. He holds a MSc in Marine Technology from the Norwegian University of Science and Technology (NTNU) with specialization in Naval Architecture, Cybernetics and Robotics.

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Sebastian Bringsværd

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Sebastian Bringsværd

Senior Vice President Offshore Wind Norway

Sebastian Bringsværd heads up the Norway region in Mainstream and is responsible for developing the Norwegian market, including our two bids for floating offshore wind at Utsira Nord and bottom-fixed offshore wind at Sørlige Nordsjø II.

Previously, Mr. Bringsværd worked at Equinor, where he was a member of the senior management team and where he built up the New Energy Division over the course of six years. In his previous position, he was responsible for establishing and heading up the floating wind unit which covered commercialization, deployment, and industrialization of floating wind in existing and new markets. He has held many leadership roles throughout his career and joined Aker Offshore Wind in November 2022. Mr. Bringsværd holds an MBA from Lancaster University, UK, and a law degree from the University of Oslo, Norway.

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Sian Lloyd Rees

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Sian Lloyd Rees

UK Managing Director

In a career spanning over 30 years Sian has extensive business experience as a Senior Leader in both Energy and IT industries, having held several leadership roles in both blue chip and start-up Companies.

Since starting her career in the Halliburton Corporation focused on North Sea and Africa, Sian has held senior positions in Oracle Corporation managing a global accounts division, was the UK MD of Aker Solutions Ltd and is currently the UK Managing Director of Mainstream Renewable Power, an Aker Company and a floating wind developer. She considers that building on the capability, solutions, and industrial heritage in the UK from oil and gas will support the scale and pace needed to deliver affordable clean energy from offshore floating wind.

Sian sits on the Boards of Serica Energy plc, Offshore Energy UK (OEUK) as co-chair and participates in other industry boards. She is also the industry Supply Chain Champion, on behalf of the UK Government and OEUK, supporting delivery of the £16billion North Sea Transition Deal.

Holger Matthiesen

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Holger Matthiesen

SVP Offshore Wind Europe and Global New Markets

Holger is in his position since 2021 and has responsibility for MRPs offshore wind development activities in Europe (outside Norway, UK and Ireland) and selected global markets.

Previous career steps included Offshore wind development and construction projects in Europe and Oil and gas exploration and production activities globally.

Holger is a trained geologist with a French engineering degree and an executive MBA. He is engaged in several non-executive board positions in industry associations.

Projects

Leading Sustainably

Blade Recycling

At present, when giant turbine blades reach the end of their working lives, there are only two options for managing the waste: send them to a landfill or to waste-to-energy plants where they are combusted at significant energy cost. Mainstream, researchers at the University of Strathclyde, and other partners are leading a wind turbine blade recycling pilot in the UK to develop a commercially viable method to separate the glass-fiber and resin components in composites and recover the glass-fiber component which can then be reprocessed, molded, and reused in new products.

Green Steel Commitments

Mainstream is part of the First Movers Coalition after Aker ASA, representing the Aker group of companies, joined as a founder at COP26. The Coalition is a buyers’ club set to fast-track the development of emerging green technologies in hard to abate sectors. Along with some of the largest companies in the world, we are working to create predictability around demand for sustainable and low-carbon materials and products.

NextWind Digital Environmental Monitoring

The NextWind project aims to create digital tools to improve the reliability, safety, efficiency, and sustainability of floating offshore wind farms through funding from the California Energy Commission. The goal is to create a data-gathering platform that can inform Mainstream’s understanding of the relationship between floating offshore wind farms and the surrounding environment in real time – from the skies to the ocean floor. The research explores how to use these data-gathering technologies on and around the floating offshore wind platform to create a digital copy of not only what is happening on the platform, but in the world around it, all in real time.

Blade Recycling

Green Steel

NextWind

Our Heritage

Mainstream has a long and rich legacy in offshore wind. From the delivery into operation of Ireland’s first offshore wind farm in 2004 as Airtricity, the development and consent of Hornsea One and Hornsea Two in England totalling 2.6 GW, to the consent of Neart na Gaoithe offshore wind project in Scotland, Mainstream has played an instrumental role in developing the offshore wind sector. Today, we have offshore wind projects in the UK, South Korea and Vietnam.

As a member of the Aker Horizons portfolio of companies, Mainstream leverages 180 years of industrial history and over five decades of offshore expertise as a developer, designer, supplier, and service provider of offshore floating and deepwater structures in harsh environments across the world. Aker Offshore Wind’s recent combination with Mainstream brings early mover positioning in floating offshore wind projects and prospects.

Floating offshore wind technology

Floating wind technology enables us to move further out at sea where the winds are stronger. The International Energy Agency believes the technical potential for offshore wind power generation could exceed 420,000 TWh per year, which is many times over the current global power demand.   

Floating wind technology is well developed and ready for commercial scale. Mainstream is a major shareholder in Principle Power, a strong technology brand in the offshore floating wind industry. 

The Benefits of Floating Offshore Wind

The world is ready for the next revolution in renewable energy – deep water and floating wind. So, what are the advantages of floating offshore wind? Check out this video to learn more.  

Frequently asked questions

What is offshore wind?

What is floating wind?

How do offshore wind farms work?

What are the benefits of floating offshore wind?

Where are floating offshore wind farms?

What is the lifecycle of floating wind?

How is offshore wind connected to green hydrogen?

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