Advancing the just energy transition

Mainstream has been advancing a just energy transition in Africa since 2009, as a developer, constructor and operator of wind and solar assets.

Our collaborations with global and local partners have added more than 1.2 GW of clean, reliable generating capacity to the continent’s energy mix in Egypt, Senegal and South Africa.

Now our focus is our multi-gigawatt pipeline of wind and solar PV assets for public and private off-takers.

BY THE NUMBERS

75+

colleagues

12+GW

in development

610MW

O&M contracts with Lekela Power (South Africa)

About Lekela Power – one of Africa’s largest renewable energy generators

Lekela Power was founded in 2015 by Mainstream and Actis, a global responsible investment firm, to help deliver sustainable, reliable and competitively-priced electricity on the African continent.

It has achieved that goal by delivering over 1 GW and is reputedly one of Africa’s largest pure-play renewable Independent Power Producers’ (IPP).  In 2022, the sale of Lekela Power was announced and reached close in Q1, 2023.

Africa Leadership Team

Julie Berg

Chief Executive Officer

Frode Strømø

Chief Transformation and Legal Officer

Daniel Ulsund

Group Head of Finance

Hein Reyneke

General Manager, South Africa

Lindsay Burgess

Head of Human Resources & Communications

Matthew Simpson

Chief Financial Officer, South Africa

Julie Berg

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Julie Berg

Chief Executive Officer

Julie joined Mainstream in 2024 as CFO, transitioning into the CEO role in January 2026, and has led the strategic transformation of the company, including the move of HQ from Dublin to Oslo in 2025.

Prior to joining the company, Julie held the position of CFO in Aker Carbon Capture (today SLB Capturi) and before that as Partner in KPMG.

Julie brings over 27 years of deep industry experience within the Energy sector. She is a distinguished leader with significant international experience and a strong ambassador for equality and diversity in the workplace.

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Frode Strømø

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Frode Strømø

Chief Transformation and Legal Officer

Frode was appointed General Counsel at Mainstream in May 2025 and is responsible for the legal and compliance functions across the Group.

He has more than 20 years’ experience and joined Mainstream from the position of General Counsel at Aker Horizons ASA, a company listed on the Oslo Stock Exchange.

Frode started his career in private practice in law firms Bahr and DLA Piper and has since held management positions in several companies within the energy sector.

Frode graduated with a law degree from the University of Bergen in 1999.

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Daniel Ulsund

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Daniel Ulsund

Group Head of Finance

Daniel joined Mainstream in May 2025 as Head of Financial Reporting and was promoted to Group Head of Finance in December 2025.

Prior to joining Mainstream, Daniel worked at Aker Horizons, an investment company within the Aker Group focused on renewable energy and decarbonisation, supporting various renewable energy investments at group level. He has previously held roles at Telenor and Aker Solutions working with IFRS, Group accounting and Consolidation. Daniel began his professional career as an auditor at KPMG in 2010.

Daniel holds a Master’s degree in Accounting and Auditing from BI Norwegian Business School, completed in 2014 and gained his CPA qualification in 2015.

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Hein Reyneke

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Hein Reyneke

General Manager, South Africa

Hein assumed the position of General Manager in 2016. He has direct responsibility for projects in development, construction and operations including taking the lead on Mainstream’s Africa initiatives late in 2016.

Since Hein joined Mainstream, his roles have included project and business development through to construction. Having worked in renewable energy since 2008, Hein has vast knowledge and experience in the industry.

Hein trained as a mechanical engineer and built a successful career in delivering complex projects and new business initiatives leading multi-disciplinary teams of professionals. His experience covers rewarding enterprises in the automotive, rail, marine and energy industries. He has been one of the pioneers of the South African renewable energy industry and a board member of the South African Wind Energy Association (SAWEA) from 2014 to 2018.

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Lindsay Burgess

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Lindsay Burgess

Head of Human Resources & Communications

Lindsay joined the Mainstream team in October 2018.  Her core function is supporting the ExCo and regional leadership teams, and all employees across the global business to ensure HR best practice, wellness and engagement. She also leads the Communication function for the Group, overseeing internal and external communication channels, media management, event sponsorships and industry memberships.

Previously, she consulted to Mainstream as a Recruitment Manager from 2012 to 2018. Lindsay has over 20 years’ experience in the recruitment and executive search consulting profession and developed core skills in interviewing, assessments, business consulting, research and project management.

She holds a Bachelor of Social Science, majoring in Psychology and HR, and a Diploma in Public Relations and Business Communication.

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Matthew Simpson

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Matthew Simpson

Chief Financial Officer, South Africa

Matthew currently holds the position of Chief Financial Officer, South Africa, with responsibility for leading the Commercial and Finance departments. In this role, he oversees the financial strategy, planning, and reporting for the South African business, while also driving commercial execution across projects. His remit includes ensuring robust governance and compliance, managing capital allocation, supporting project financing and investment decisions, and aligning commercial outcomes with Mainstream’s broader strategic objectives.

He joined Mainstream in 2021 as Head of Commercial, Africa, where he led the commercial function to secure PPAs for wind and solar PV projects, covering tendering, structuring, negotiation, due diligence, and ultimately financial close.

Before joining Mainstream, Matthew worked at Eaglestone Capital Advisory, a project finance advisory boutique, where he advised power and infrastructure clients on corporate and project finance transactions across Africa. Prior to that, he was part of the infrastructure sector team at Macquarie Capital Johannesburg, specialising in financial modelling, transaction execution, and debt and equity procurement advisory.

Matthew is a Chartered Accountant and a member of the South African Institute of Chartered Accountants, having completed his articles at KPMG Johannesburg in the financial services sector.

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Related Projects

Onshore wind
Offshore wind
Solar PV

Our team’s dedication to our country, coupled with our solid track record here, underpins our commitment to delivering renewable energy here in South Africa for many more decades to come.

Hein Reyneke – General Manager, Africa

CONTACT US

Cape Town Office

4th Floor Mariendahl House
Newlands on Main
Corner Main & Campground Roads
Claremont
7708, Cape Town

+27 (0)21 657 4040

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