In a UK first, energy giant RWE has successfully trialled bubble curtain technology at its Sofia Offshore Wind Farm to protect marine life from the noise generated during offshore wind construction.
A Breakthrough for British Waters
This kind of system, already in use across parts of Europe, is designed to dramatically reduce the impact of underwater noise during piling, i.e. the process of driving huge steel foundations into the seabed.
RWE and Hydrotechnik Offshore
RWE, one of Europe’s largest renewable energy firms, is leading the project. With decades of experience in power generation, the company has increasingly focused on sustainability and innovation within its global offshore wind portfolio.
At Sofia, RWE has partnered with Hydrotechnik Offshore, a noise mitigation expert known for its proven track record on bubble curtain systems. The offshore wind farm where the bubble curtain technology has been trialled by this partnership is Sofia, a 1.4GW project currently being built on Dogger Bank, some 195 kilometres off England’s north-east coast.
In a Special Area of Conservation
The RWE / Hydrotechnik Offshore collaboration marks a major leap in environmental responsibility, particularly in a zone as sensitive as the Southern North Sea Special Area of Conservation (SAC), where noise regulations are tightly controlled due to the presence of harbour porpoises.
Matthew Swanwick, RWE’s Sofia Project Director, described the trial as “a strengthening of our commitment to environmental responsibility,” adding that such technologies make it possible to develop offshore wind “with minimal impact on marine life.”
How the Bubble Curtain Works
As unusual as it sounds, a bubble curtain deployed in this way can actually be a precisely engineered solution. The curtain has been created in this case by laying a perforated hose in a ring (around 180 metres in diameter) on the seabed around the monopile installation site. When compressed air is pumped through the hose, this is what creates the dense column of rising bubbles that forms a barrier (kind of curtain of bubbles) in the water column.
How The Bubbles Stop Noise
The bubble curtain at the Sofia Offshore Wind Farm is intended to be used to protect marine life from the noise created during offshore wind construction. The bubbles reduce this noise by breaking up and slowing down the transmission of low-frequency sound waves that travel through the water during pile driving. The aim of reducing the underwater noise levels in this way is to minimise the kind of noises that are known to disorientate or harm marine mammals such as whales, dolphins and harbour porpoises.
For example, animals like the harbour porpoise rely heavily on ultrasound for navigation and hunting. Intense man-made noise can interfere with these natural systems, causing stress, behavioural changes, or even driving them away from their habitat. The bubble curtain helps to prevent that.
Why It’s Needed Now
The need for such measures has become more urgent as offshore wind scales up. Construction activities (especially piling) can generate underwater noise levels exceeding 200 decibels. Without proper mitigation, this can seriously disrupt sensitive marine ecosystems.
Also, with the Sofia project being built inside a designated SAC, the use of noise abatement technology was not just a preference, but a necessity. This is because the area is protected under EU conservation rules, and UK regulations also require developers to assess and mitigate environmental impact, especially to protected species.
It’s also worth noting here that public and regulatory scrutiny of offshore developments has increased in recent years, particularly as the UK ramps up its transition to net zero. It’s hoped, therefore, that innovative technology like this can help pre-empt opposition and reassure stakeholders that wind energy can expand without sacrificing ecological wellbeing.
Sofia and Sustainability
The bubble curtain isn’t the only sustainability win at the Sofia Offshore Wind Farm. For example, the £3 billion project is also packed with many other green firsts, including:
– Half of its 100 Siemens Gamesa 14MW turbines will use recyclable blades, which is the highest percentage seen in any major wind project to date.
– The project is deploying two world-first service operation vessels powered by methanol and batteries, slashing up to 10,000 tonnes of CO₂ emissions annually.
– RWE is also backing marine conservation initiatives, including a £25,000 donation to North Sea Conservation, which supports the Whitby Lobster Hatchery, and funding for Clean Planet UK to tackle ‘ghost fishing’ gear in UK waters. Ghost fishing gear includes lost/discarded lines, nets, traps etc.
This suite of sustainability actions looks like placing Sofia at the forefront of responsible offshore development.
How It’s Going So Far
It’s worth noting that the project is still under construction, with piling for the turbine foundations getting underway earlier this year. Offshore installations have been led by Van Oord’s jack-up vessel Aeolus, and by March, more than 60 foundations were already in place. The first turbine was installed soon after using Cadeler’s new Wind Peak vessel.
Bubble Curtain Results Promising
According to RWE, the bubble curtain was trialled during these early phases and delivered a notable reduction in underwater noise propagation, though specific decibel reductions have yet to be made public. However, Swanwick has confirmed that “initial results have been promising” and hinted that the technology may now become standard on future UK projects where marine biodiversity is at risk.
Globally, the system has already shown its worth. For example, it was previously deployed at Vattenfall’s DanTysk project in Germany back in 2013, and more recently at EnBW’s He Dreiht wind farm and the Vineyard Wind 1 project off the US coast. In each case, the bubble curtain has helped balance construction progress with environmental stewardship.
Why It Matters for the Industry
The successful UK deployment of bubble curtain technology is more than a scientific milestone because going forward, it could also change how offshore wind is built.
As construction ramps up on the UK seabed, with gigawatt-scale projects now the norm, concerns over marine impact have been growing. Developers are under pressure to deliver green energy without greenwashing. Technologies like the bubble curtain, therefore, offer a credible, science-based way to address these challenges.
It may also offer some commercial advantages. For example, projects that demonstrate strong environmental credentials are increasingly likely to win regulatory favour, attract funding, and maintain public support. That means early adopters like RWE may now be well-positioned to lead the next wave of sustainable infrastructure.
For the UK, which is targeting 50GW of offshore wind capacity by 2030, the lessons from Sofia could ripple far beyond Dogger Bank.
What Does This Mean For Your Organisation?
The deployment of bubble curtain technology at Sofia shows how sustainability and large-scale infrastructure can go hand in hand. By trialling and proving the effectiveness of this system in UK waters, RWE may have opened the door for wider adoption, not only in future offshore wind developments but potentially in other marine-based construction projects too.
For UK businesses involved in renewable energy, marine engineering, and environmental consultancy, this could be significant. For example, it shows that meeting environmental obligations doesn’t have to slow progress, and it can actually support it. As the offshore wind sector grows, demand for noise mitigation solutions and other responsible construction practices is likely to grow with it. This could create fresh opportunities for companies offering related services, equipment, and expertise.
At the same time, regulators and policymakers will, no doubt, be watching closely. The Sofia project could serve as a valuable case study in how early investment in environmental technology can reduce risks and build stakeholder trust. It also adds weight to the argument that the UK can lead not just in offshore wind capacity, but in how that capacity is delivered safely, sustainably, and in harmony with nature.
For conservation groups, the positive early results from Sofia may offer a note of cautious optimism. While challenges remain, this trial proves that mitigation efforts can be meaningful and measurable. For the public, whose support underpins the clean energy transition, it may help reinforce the idea that green energy doesn’t have to come at the cost of local ecosystems.
What’s happening at Dogger Bank is really a testbed for the kind of innovation that could define the next chapter of the UK’s net zero journey where sustainability is no longer a bolt-on, but a central part of how we build the future.