Second wind
A pioneering onshore wind farm on Orkney is seeking to make history once more. Utility Week heads to the Scottish island as the project’s developers grapple with the realities of repowering.
By Rob Horgan, International Editor
Second wind
A pioneering onshore wind farm on Orkney is seeking to make history once more. Utility Week heads to the Scottish island as the project’s developers grapple with the realities of repowering.
By Rob Horgan, International Editor
For Melissa Spence, growing up with wind turbines in her back garden felt as ordinary as playing among the nearby Neolithic ruins. Only now, as managing director of that wind farm, does she realise that neither experience was a particularly common one for children growing up in the UK.
Orkney, though, has long made the extraordinary feel everyday. The island is steeped in Neolithic history and in more recent decades has helped lead the world in renewable energy generation.
On Burgar Hill, which runs behind Spence’s childhood home, are six wind turbines with a production capacity of 12.5MW. The site has been at the forefront of onshore wind development for decades. It has some of the best wind resource in Europe, a pioneering history and an engaged community.
In theory, it is exactly the sort of place Britain should be repowering. In practice, the task is proving much harder. Utility Week headed to the Scottish island as this revolutionary site seeks to write its next chapter.
History maker
Burgar Hill has been at the apex of wind energy research and innovation since the 1980s, after Spence’s grandfather spotted an opportunity to capitalise on Orkney’s particularly breezy climate. Wind speeds on the hill are on average above 10m/s (22.4mph), double the UK average and 50% higher than mainland Scotland averages. It is for this reason that the island is virtually treeless, something immediately noticeable as you touch down on the island’s airport.
Burgar Hill was part of a broader effort to explore renewable energy solutions in response to the energy crises of the 1970s. The first experimental turbines arrived when Spence was a child. Three machines were installed, including a 200kW turbine, a 300kW turbine and one of the world’s first 3MW grid-connected wind turbines.
By the 1990s the focus shifted from experimental research to commercial production and in the early noughties the site which remains there today had taken shape.
The wind turbines are now at the end of their operational life and Spence is seeking to follow in her grandfather’s pioneering footsteps by breathing fresh life into the ageing infrastructure.
Burgar Hill Energy, a joint venture between Spence’s family business Burgar Hill Renewables and international developer Thrive Renewables, wants to replace five of the existing turbines with five newer machines. The repowered scheme could more than double the site’s output to between 25MW and 30MW, using broadly the same hilltop footprint.
The need to repower
On arrival at the Burgar Hill visitor centre, just one of the site’s six turbines is slowly spinning on an uncharacteristically still day on Orkney.
While an unexpected absence of wind is playing its part, the lack of activity is largely attributable to the condition of the turbines – with four of the site’s six currently out of action and awaiting repairs.
The turbines are between 17 and 26 years old, which is at or beyond the typical operational life of 20–25 years, especially given Orkney’s harsh, windy conditions and the fact that these are early models. And the scars of a hard life are there for all to see, with rust covering large sections of the turbines’ central columns.
Maintenance challenges include difficulty sourcing spare parts, as most models are no longer manufactured, and logistical complexities due to the site’s remote location. Major repairs in the last six to eight years have included replacement of two generators, multiple gearboxes, some blades, and a yaw bearing (the mechanism that allows the turbine to turn into the wind).
The infrastructure, in short, is on its last legs. “Until about five years ago, all the turbines were running,” Spence explains. “There is maintenance ongoing all the time, but we’re seeing more and more big repairs.”
She adds: “They've had a tough life, a hard-working life, and it's obvious that they're getting to the time that they need replacement. It's just getting harder to get spares for these old machines. Most of these models are no longer in construction, or in manufacture, and there's an added logistical complexity with the site being on Orkney."
Despite their hard life, the turbines have also had a record-breaking existence, leading from the front of the UK’s transition to renewable power. One of the NEG Micon NM92 turbines was the first single turbine in the UK to generate over 100GWh – and it reached that milestone over a decade ago.
“They’ve had a tough life, a hard-working life, and it’s obvious that they’re getting to the time that they need replacement.”
Melissa Spence, managing director, Burgar Hill Renewables
“They’ve had a tough life, a hard-working life, and it’s obvious that they’re getting to the time that they need replacement.”
Melissa Spence, managing director Burgar Hill Renewables
Planning hurdle
On the face of it, Spence says repowering should be easier than building on a new site. However, the experience at Burgar Hill shows the reality is more complicated.
A lack of consistency in the planning process quickly emerged as a major issue. Noise, landscape, visual impact and cultural heritage assessments do not all treat the baseline in the same way. In some cases, the existing turbines must be stripped out of the modelling. In others, the comparison must demonstrate the incremental impact of larger machines where turbines are already present. Some turbines also have different consent timelines, making the “future baseline” difficult to pin down.
“I would have thought that a repowering application would be easier than a greenfield site,” Spence says. “To be honest, it feels like it’s been harder, because we’ve had to do some assessments as if the turbines weren’t there. We’ve had to do some with and without. It’s added work to the planning application rather than streamlining anything.”
It is an issue beyond the Burgar Hill project, Thrive Renwables chief executive Matthew Clayton adds. Much of the UK’s first significant build-out of onshore wind is approaching or passing the end of its original life. If every repowering project has to navigate bespoke uncertainty over baselines and assessment methods, Britain risks losing as much as half the existing 15.9GW of onshore wind capacity of the generation it already has in place, he warns.
“We could increase the capacity on a site fourfold and deliver stacks more power, solve environmental problems, and contribute towards the national [clean power] targets. But where the brakes start to get applied is the planning system and grid access,” Clayton explains. “What we’re seeing is that the repowering considerations haven’t been put into the spatial planning frameworks. So, the fact that there’s existing capacity there that may want to grow its capacity isn’t given any forethought.”
Clayton acknowledges that planning reforms implemented during the past two years have helped. This includes the removal of restrictions (which functioned as a de facto ban) that allowed single objections to block projects.
Large onshore wind projects (over 100MW) are also now being re-introduced into the Nationally Significant Infrastructure Project (NSIP) regime, which provides a different, often faster, consent route than local authorities. And an Onshore Wind Taskforce has been formed to devise a new strategy that is focusing on accelerating deployment to meet 2030 targets.
“Whilst planning has evolved a lot from where it was, repowering hasn’t really been given due consideration when really it should be encouraged,” Clayton adds. “There’s still no standard approach to repowering. With all the projects we’ve done so far, the planners haven’t had any benchmarks or precedents to work from.
“There’s no real national guidance as to what the benchmark is. Should planners be judging an application against the existing site, where there’s a wind farm there already. […] Or do they have to turn back the clock 25 years to before there was a wind farm there at all and use that as your benchmark? Because we don’t have an answer to that we’re having to make dual submissions reflecting both scenarios at the moment.”
Clayton also wants to see repowering projects treated differently when it comes to connecting to the grid. He said that repowering schemes are currently treated as new projects, rather than extensions of existing infrastructure, and therefore they are automatically placed at the back of the queue, even if the generation capacity is remaining the same.
“It’s not a capacity issue, it’s a contractual issue. If it’s a physical problem and there wasn’t the capacity and additional infrastructure was required on the grid side, then I would get it,” Clayton says. “But it’s often not the case so that’s an element which I find a little bit frustrating too.”
Looking forwards, given the desire to expand onshore wind generation, Clayton says that new developments should be given planning in perpetuity to avoid another potential cliff edge moment. “Planning into perpetuity would be a good place to start,” he adds. “I think the concern in the very early days was that wind farms were a bit wacky and weren’t going to last, so they built in the protection that if it didn’t work, they would be dismantled. But that’s not a concern anymore.”
Community interest
The need to obtain new consents for repowering schemes also opens the door to objectors. With new plans comes renewed interest from the community. And the Orcadians are more clued up than most when it comes to debating energy.
With an hour to kill before my visit to the Burgar Hill site, I head to the picturesque town of Stromness to gauge the local opinion of the windfarm’s repowering plans. On my first stop, Elaine from Arts and Gifts at 59 perfectly makes the case for locational pricing, arguing that if Orcadians have to look at the turbines, then they should feel that in their back pocket. It was a similar story at Loki’s fish shack where Lee complains about the amount of time turbines are curtailed on the island, while in Alison Moore jewellers Heather makes Burgar Hill’s repowering argument for them: “They’ve always been there, they are not ugly, so I don’t understand the issue”.
Community Energy Scotland technical director Mark Hull – who is also a community councillor on Orkney – explains that the community’s collective interest in its energy is driven by two things: high levels of fuel poverty and the geographical risks posed by living on an island. “Orkney has, for many years, been among the most fuel-poor areas in the country,” Hull says. "When the ferries aren't running, it's howling a gale and the power has gone off, you feel that vulnerability, so you're much more aware of what you're relying on as well."
Despite that interest, support isn’t a given. Burgar Hill sits in a topographical bowl, partly screened by surrounding ridgelines, but larger turbines would still be more visible from some historical locations, such as the Ring of Brodgar (Orkney’s equivalent of Stonehenge). The project’s developers initially tabled a more ambitious option to replace five turbines with four machines of up to 200m tip height. While residents were broadly supportive of repowering, they questioned the need to go so large in a sensitive island setting.
Burgar Hill Energy responded by revising the design to five turbines of up to 149.9m. That decision reduces visual impact and avoids the need for aviation lighting, an important point in a place known for winter views of the northern lights. Spence says the smaller design may mean a 10% to 15% yield reduction, but calls it “the right thing to do”, adding that there was a “much greater level of comfort” once the design was changed.
Spence adds that one advantage Burgar Hill has is familiarity. During my visit, several locals turn up to walk their dogs on the hill between the turbines. The developer is not an anonymous outside fund, but a joint venture involving a local family business embedded in the community.
Original tip height of turbines
Revised tip height after consultation with locals
Resultant hit to output
While Spence may not have the weight to influence national decisions on locational pricing, Burgar Hill Energy is keen for the local community to benefit from the repowered project. The company has put forward a community benefits package to provide around £150,000 a year and has committed to exploring up to 10% local ownership if the community wants it.
Hull said that renewable energy projects can be a lifeline for the local community. He adds: “For islands that were once depopulated and really threatened, community energy has given us a chance to carry on – it’s not political independence, but at least it gives us one hand on the steering wheel of our own future."
For Spence, the project is partly about proving that an onshore wind farm can coexist with the place around it. “It feels good to be able to support the community,” she says. “This is a small place, and Orcadians are very modest people. To be able to help improve the community and the amenities that we have through the project will be good.”
She adds: “We are Orcadians, we're part of this community, and we're able to be a local resident, a responsible developer, somebody that's got all the things in mind."
Burgar Hill’s repower is not simply a local development story. It is a stress test for the UK’s ability to renew its ageing fleet of first-generation wind assets. Burgar Hill’s experience has exposed several policy gaps and barriers which need to be taken down. Its repowering offers the chance for the historic site to once again set a precedent for the UK’s wider clean power push.
