Balance needed between underground and overhead lines, SSEN managers say
The first of a series of ‘Shetland Strategy’ consultation events was held on Monday in Mossbank
BURYING more cables underground to have less overhead lines would result in larger substations, according to SSEN officials visiting Shetland on their latest round of consultation.
Decreasing the height of proposed ‘pylons’ around Voe and up to Toft could also increase the need for infrastructure, they said.
It comes as a series of engagement events kicked off at the Mossbank Hall on Monday afternoon, with the focus there being on the northern substation hub proposed for Toft.
In an interview beforehand with Shetland News, SSEN Transmission’s development portfolio manager David Inge and lead development project manager Cath Swan also said that:
- “All options” are being considered for accommodating visiting construction workers
- There is no frontrunner yet for a landfall site for a second HVDC subsea cable to Shetland, but the east of the isles is “challenging” from a geology perspective
- There are hopes to hold another Shetland-wide engagement event in the future
SSEN is going back out to the community this week on a suite of potential projects designed to facilitate future energy developments, including onshore and offshore wind farms.
This includes substations, overhead lines and underground cabling – both in the mainland and in Yell – as well as a second subsea HVDC link between Shetland and the Scottish mainland.
One of the most contentious issues is 38-metre high overhead lines planned between a new substation south of Voe and the proposed northern substation hub in Toft.
A petition with more than 1,600 signatures was launched by Voe residents against the the so-called pylons, and plans have since been refined to place some sections around the village underground.
But the fact that the large overhead lines are proposed to run parallel to the A968 Dales Lees road has caused concern.
When asked if more lines could be placed underground, Swan said “we are looking at it”.
But she said “the more and more sections of undergrounding we have, it means that the substations get larger, so there’s additional equipment needed”.
“So it’s getting that balance between the environmental, community and finding a way through that.”
Swan said there are a number of factors why overhead lines are the preference to begin with over underground cabling, pointing to Shetland’s peatland.
The large 38-metre ‘pylons’ would be 220kV lines, but energy regulator Ofgem has queried this because larger structures – such as 275kV or 400kV – could provide additional future capacity.
But Swan said SSEN is continuing to push for 220kV lines to reduce the visual impact, despite this voltage not being common for overhead lines in the UK.
She said discussions with Ofgem are still ongoing, with a final decision expected from the regulator later this year.
Inge, however, said going smaller than 220kV would mean more infrastructure would be required.
“Part of that that technology choice around 220 is to minimise the amount of overall infrastructure that’s required on the island, both from a substation perspective and from an interconnection and cable perspective,” he said.
“That’s a key strategic choice to try and minimise the impact to communities.”
In Toft the large northern substation hub is proposed for land near to the ferry terminal.
An indicative site boundary reaches 180 to 200 hectares in area but that is likely to be refined down, and it includes more than just the buildings, such as laydown areas and drainage.
The substation buildings, though, are expected to be significantly larger than the existing Kergord one – particularly because the second HVDC cable which would link into it could be 1.8GW, or three times the capacity of the existing one.
There are a handful of landfall sites under consideration for the HVDC cable coming ashore in Shetland, including the Toft area as well as Braewick in Eshaness and near Mavis Grind.
The latter two – on the western side of Shetland – are new additions to the list of potential sites.
Inge said the east of Shetland is challenging from a geology perspective, but no final decisions have been made as surveys continue.
Due to the type of cabling, there would be underground lines from the landfall site to the northern substation hub, which could span many miles.
Swan said there is “no easy option” for landfall sites as the marine environment meets with the onshore element.
Elsewhere there is a substation proposed for Yell too, as well as overhead lines, to facilitate Statkraft’s planned Energy Isles and Beaw Field wind farm.
With construction on the first project set to get underway in 2028, all options remain under consideration on where to accommodate the workforce.
A council meeting recently heard that there could be 1,500 workers needed, but Inge said this would represent a peak.
The meeting was also told that barges and accommodation camps are under consideration alongside ‘legacy housing’, where homes are given back for community use after workers have left.
Inge said all options remain under consideration, despite concerns that the clock is ticking towards construction.
“It’s about temporary and local solutions and as well as legacy solutions as well,” he added.
There are six Shetland Strategy meetings this week, with the next at the Voe Hall later today from 3pm to 8pm.
On Wednesday there will be an event at the Mid Yell Hall from 1pm to 5pm before the team heads to the Burravoe Hall from 6pm to 8pm.
On Thursday the focus will shift to the second HVDC cable, with an event at the Brae Hall from 11am to 1pm and another at the Hillswick Hall from 3pm to 7pm.
Given the number of projects on the horizon, as well as previous and ongoing developments, one criticism has been that consultation events are split up and do not generally take account of cumulative impact.
Swan, however, said SSEN are looking to host another Shetland-wide engagement event like the one held at Mareel in September.
Despite continued concern that developments are being done to Shetland rather than with Shetland, Swan said “we are listening”.
But she reiterated that SSEN are obligated to undertake the works to facilitate renewable energy development.
“There are consented wind farms and we have to provide a means for them to be connected,” Swan added.
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