ARENSO: A Start-Up With 25 Years of Experience
Following a recent management buyout, Arenso is now a fully independent engineering house, capable of servicing the entire offshore wind market, using a quarter century of experience developing some of the world’s most complex offshore projects in freezing arctic conditions. Director Esa Holttinen tells Energy Focus more about structural changes and ongoing projects.
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Interview with Esa Holttinen, Director
In May 2025, Arctic energy solutions company, Arenso, was navigating the early stages of a market it had helped define. Business Director Esa Holttinen described a company leveraging hard-won knowledge from Europe’s first offshore wind farm built for icy conditions — Tahkoluoto — to position itself as the go-to technical partner for developers pushing into the northern Baltic. The pipeline was building, projects around the Baltics were advancing, and Arenso was making the case that the region’s perceived challenges were, in the right hands, a competitive advantage.
Much has changed since then, and much has not. The structural shift is significant: Arenso is now management-owned, following a management buyout completed in February 2026. Managing Director Toni Sulameri holds a majority stake alongside two minority shareholders, and the offshore wind business — including the Arenso brand and all associated expertise — has been fully separated from its former parent. The previous entity has reverted to the Hyötytuuli name and refocused on onshore activity.
“Arenso is now management owned following the buyout,” Holttinen explains. “That means we are completely independent of all suppliers, contractors, and energy producers. We are now fully capable of partnering with clients of any kind and we have zero conflicting interest with any wind project developer or investor.”
The logic behind the transaction was straightforward. The former owners recognised that running an engineering consultancy was not aligned with their core business, and the management team saw an opportunity to unlock the company’s full potential.
“The previous owners did not believe they were the perfect fit for an engineering company,” Holttinen says. “To reach a solution quickly, the management buyout was the best solution to achieve all targets.” The result is a leaner, sharper business — fully independent, entirely focused on offshore, and free to pursue relationships across the full spectrum of developers, investors and contractors without the conflicts of interest that came with the previous ownership structure.
The result is a unique situation where a highly experienced team of professionals is running what is effectively a fledgling business. “We are now in a start-up situation which has its own unique challenges,” says Holttinen. Twenty-five years of accumulated expertise, a proven track record on one of the world’s most technically demanding offshore wind projects, and a clean balance sheet — but the commercial and operational realities of a business that must now build its client base and revenue pipeline from scratch. It is a distinctive position, but one that Holttinen is not afraid of having spent a career navigating difficult markets.
EBBA AND METSÄHALLITUS
The clearest sign that Arenso’s expertise remains in high demand came in September 2025, before the buyout was even complete, when Metsähallitus — the Finnish government body responsible for state-owned land and territorial waters — commissioned Arenso to lead the technical design work for the environmental impact assessments (EIA) programme phase of the Ebba offshore wind project. The Ebba site lies in the Bay of Bothnia, in the northern Baltic, and forms part of Finland’s broader push toward carbon-neutral energy production. Arenso’s role covers early-stage technical design feeding directly into the environmental impact assessment process — the kind of foundational work that determines whether a project can advance to permitting and eventually to construction.
It is precisely the kind of commission that underlines what Arenso offers that others cannot easily replicate. The Bay of Bothnia presents some of the most demanding conditions in the Baltic: shallow waters, complex ice loading, variable seabed conditions, and seasonal constraints that make both the engineering and the EIA process significantly more involved than equivalent work in the North Sea or warmer Baltic waters.
“This process is adapted to the region and involves working around different site conditions in terms of soil, ice, weather etc,” Holttinen explains. “You cannot copy and paste what would be done in the North Sea. Many of the processes are standard engineering processes but taking into account local conditions.”
Arenso’s broader relationship with Metsähallitus extends across several fronts. “We work a lot with Metsähallitus, and we are supporting them with early-stage development work, providing EIA, spatial planning, technical engineering input, and process review — that is one of the main things we are busy with right now,” says Holtinnen. The spatial planning work is particularly significant: in offshore development, spatial planning performs the equivalent function to a land use plan onshore, feeding into the permitting process and forming the technical and stakeholder framework through which a project moves toward consent.
Getting this right — working with local and regional authorities, establishing cable routes and layout parameters, managing the interface between competing sea uses — is slow and detailed work, and it is work that demands exactly the kind of regional knowledge Arenso has spent decades accumulating.
Alongside new projects, Tahkoluoto continues to occupy a central place in the company’s activity. The project that first established Arenso’s reputation — Finland’s first commercial offshore wind farm, and the template for arctic offshore engineering in the region — is still working through its remaining permitting requirements, including the critical grid connection. “We are still focused on those key elements as they are critical for the value of the project,” Holttinen confirms. “We have interest from many financiers but they want to see us move forward with the remaining permitting and securing of the grid connection — these things take time and money.”
A recent independent study commissioned by Tahkoluoto Offshore confirmed that a fully built-out project would have a major positive impact on regional employment and the local economy, strengthening the commercial case at a time when investor interest is beginning to stir.
PATIENCE AS STRATEGY
The wider Finnish offshore market is markedly quiet. The same macroeconomic and geopolitical headwinds that have slowed offshore wind development across Europe and around the worlds have hit smaller, emerging markets particularly hard. The attraction of the North Sea — scale, established supply chains, clearer regulatory frameworks — continues to pull the attention of contractors, turbine suppliers and financiers away from Baltic developments. “The good news for the North Sea markets is bad news for us,” Holttinen says. “All of the big players, not just in finance but also contractors and turbine suppliers, have all eyes on the North Sea market. Smaller, emerging, early-stage markets are put to the sidelines, and that makes things very challenging.”
The response is not to wait passively. “We are always promoting the fact that it remains worthwhile putting effort into things that move forward slowly like permitting and basic engineering studies so that developers can move quickly when market conditions change — and that could happen relatively quickly. I would not be at all surprised if things look very different in just two years from now,” he says. There are already signals. Power consumption in Finland is rising, driven by data centre expansion and electric boilers for district heating among other critical projects.
Electricity spot prices are also climbing. “We see weak signals from the finance community that there is growing interest in investing in wind projects in general,” Holttinen notes. Data centre developers — an exciting new customer category — are beginning to engage directly with offshore wind developers, attracted by the premium capture price that comes with the first wave of offshore generation in any market. “There seems to be a premium around the first offshore wind farm, and that tends to have a better capture price compared to onshore wind. It’s a new customer category for us but the conversations are very interesting.”
Internally, Arenso is investing for that moment. An application has been submitted for public financing to develop an AI-based project management and document management system specifically designed for offshore wind. “We expect it to bring us to a competitive position compared to bigger engineering offices when it comes to project management in offshore wind,” Holttinen says. “It’s not just about software development — it’s about developing methods and standardised tools to improve efficiencies.”
For a lean team competing in a market where scale and resources often favour larger firms, that kind of capability could be genuinely differentiating.
The macro picture for the Baltic provides the context for everything Arenso is doing. A joint system study published in January 2026 by eight transmission system operators surrounding the Baltic Sea — including Finland’s Fingrid — identified potential for up to 50GW of new offshore wind capacity in the region by 2040, with Poland, Finland and Sweden leading growth, supported by 13GW of new cross-border interconnectors. The Baltic’s installed base remains a fraction of its potential, and the countries bordering it have committed to expanding from roughly 3GW today to 19.6GW by 2030. Every megawatt of that growth requires the foundational technical work — EIAs, spatial planning, foundation engineering, grid interface design — that Arenso specialises in.
Beyond the Baltic, Holttinen sees possibilities in markets facing similar challenges. Eastern Canada, with its own sea ice conditions and an emerging interest in offshore wind, is one region where Arenso’s expertise could travel. For now, the focus remains on Finland and the northern Baltic, where the company’s combination of depth of knowledge, independence, and readiness to work through slow markets is exactly what the next phase of the region’s offshore wind development will require.
“It is a strange combination,” Holttinen reflects, “because we are a start up with 25 years’ experience.” In the Baltic offshore wind sector, that combination may prove to be exactly what is required.