On a remote headland dubbed Britain’s only desert and one of the most precious shingle habitats in Europe, essential refurbishment is taking place on the overhead power line that transports vital energy across the region.
Juttting three miles into the English Channel at Britain’s most south-easterly point, the 12-square-mile headland of Dungeness is a desolate and surreal place.
On the foreshore, beneath the huge Kentish skies and distant horizons of this eerily flat landscape, fishing boats and wooden houses lie abandoned.
Despite the presence at Dungeness of gravel extraction pits, an airport, army firing range and a nuclear power station, nature has survived and thrived.
The headland is a designated National Nature Reserve, Special Protection Area, Special Area of Conservation and Site of Special Scientific Interest (SSSI), with the largest area of vegetated shingle in Europe. The habitat is home to 600 types of plant (a third of all those in Britain) and a variety of rare bees, moths, beetles and spiders.
Dungeness nuclear power station has supplied low-carbon energy to the grid for nearly half a century and the 25km-long 400kV overhead power line that connects it with Sellindge substation is being refurbished.
The line is part of the transmission network that runs from the Greater Thames Estuary, along the North Kent Plain and on towards Sussex and the south-east.
Refurbishment on the 85 towers by contractor Balfour Beatty took place in two power outages between March and November this year. As well as new conductors and insulators, sections of steel are being replaced and towers repainted.
A new 400kV substation is also being built alongside the substation at Sellindge, providing extra capacity for the transmission system and supporting new power generation in the area. The Sellindge site already hosts the converter station for the existing 2000MW IFA1 interconnector with France, which this year marks its 30th anniversary.
A separate driver for the refurbishment is to reinforce the network ahead of the proposed 1000MW NEMO Link interconnector with Belgium at Richborough, in Kent. Interconnectors are vital for energy security, meeting demand, while managing intermittent supply from renewable energy sources such as wind or solar.
Here is how National Grid and our partners worked closely together to make the refurbishment happen.
Alison Williams, National Grid land officer south-east
I started contacting the 55 grantors on the route in March 2015 to agree access routes to towers, as well as requirements for scaffolding and working areas.
As a land officer in the area for 12 years, I already had a good working relationship with many of them.
“We checked that we had accurate records about the owners and occupiers of land so we could contact them about essential maintenance”
Early engagement with landowners enables both parties to understand the impacts on affected land, with a view to minimising disruption.
Much of the route crosses the low-lying Romney Marsh, where the land is devoted to arable crops like potatoes or wheat, or set to pasture for cattle or sheep.
A landscape feature here is the drainage ditches, locally called ‘sewers’, and as part of the consultation process, we liaised with the Internal Drainage Board.
The MOD is the single largest grantor on the line, having 22 towers on the 3,000-acre Lydd Ranges.
During the project we checked that we had accurate records about the owners and occupiers of land so we could contact them about essential maintenance.
The job isn’t finished until grantors are happy with the way we have left their land and that all agreed reinstatement has been carried out to their satisfaction.
Graham Livings, National Grid project engineer
On this project, the line’s new conductors have been pulled into place using the old wires.
Raising the replacements from the ground would be far more disruptive and would risk damaging them.
In March 2015, contractor Balfour Beatty began looking at site-specific factors, such as how best to access individual towers and complete the works efficiently and in total safety.
“240 people, including 90 linesmen and a host of other specialists, have worked on the refurbishment, necessary to ensure safe and reliable energy supplies into the future”
The safety of the public and our workforce is key and to make sure they are protected from the work above, scaffolding with protective nets has been used at busy road and rail crossings.
Where scaffolding would cause too much disruption, other options are road and footpath closures or a catenary support system (CSS).
This has allowed safety cables and machinery to be suspended between towers to prevent the loss of the conductor in the unlikely event of failure during installation.
More than 240 people, including 90 linesmen and a host of other specialists, have worked on the refurbishment, which is necessary to ensure safe and reliable energy supplies into the future.
CSS has been deployed where the route crosses a rail track used by the busy HS1 services between St Pancras in London and the Channel Tunnel, as well as a Network Rail service, a minor road and a 132,000-volt local distribution electricity line.
David Smith, Middlemarch Environmental
Our company, owned by the Warwickshire Wildlife Trust, is advising the team on ecology aspects of the project.
About a third of the entire route lies in a SSSI. Our first task in June last year was to verify the findings of previous baseline ecological assessments about the presence of protected and notable species.
One of our key priorities has been to ensure two rare types of lichen habitat at Dungeness are protected. Crustose lichen, which colonises undisturbed bare shingle, is visible as a black crust on the upper side of pebbles, while Cladonia heath lichen grows in low bushy clumps and is grey/green in colour.
To avoid disturbing the shingle, we used a temporary trackway, made of a lightweight hard plastic, to access affected towers, which had a special reflective surface to protect the lichen from excessive heat build-up.
In consultation with Natural England, trackway use was limited to five weeks for crustose lichen and three weeks in the case of Cladonia heath.
We also successfully trialled a new kind of sledge for the tractors and the winch points needed for restringing, which are anchored to the ground to prevent slippage and damage to the shingle.
- Dungeness B, which began operations in 1983, generates enough electricity to power 1.5 million homes. Dungeness A, which came online in 1965, is currently being decommissioned.
- The UK’s 16 nuclear reactors at 9 plants generate about 21% of its electricity.
- Nuclear plants help meet climate change targets as they operate on a closed loop cooling system and don’t emit carbon emissions when they burn fuel, unlike coal or gas.
- There are proposals to install 18 gigawatts of new nuclear at 6 sites: delivering 30% of our electricity in the 2030s.
Christine Evans, Copper Consultancy
We are carrying out the community relations role for National Grid. Our priority is to establish good relations with local people and community representatives, raising awareness of why the work is necessary and how it will be done.
Letters and project leaflets were sent out to 546 properties along the route. We also kept people up to date about road or footpath closures in conjunction with road signage to indicate diversions.
In June 2015 we gave a presentation to Lydd Town Council, attended by councillors, residents and the local media, setting out how environmental specialists would ensure the works had no long-term impact.
Local people were reassured that a traffic management plan was in place for construction vehicles, and as part of their induction process, all field operatives were also reminded to use only agreed access routes and parking areas.
We met affected parish councils, and team members visited two local primary schools to deliver Mad Science shows and workshops promoting STEM (science, technology, engineering and maths) subjects.