Hunterston converter
station & cable

A converter station is needed at Hunterston to convert the direct current (DC) electricity to alternating current (AC) so that it can be used within the existing electricity transmission system.

Converter station

In addition to installing a new high voltage connection, we needed to convert the direct current (DC) electricity to alternating current (AC) at each end so that it can be used within the existing electricity transmission system. To do this, we needed to build a converter station at each end.

In Scotland, the converter station is sited in Hunterston, on the north face of Goldenberry Hill and adjacent to Hunterston power station.The site at Goldenberry Hill is the preferred location as it is situated close to the shore, adjacent to a significant industrial area and within an area that is not densely populated.   

The converter station connects to a new substation adjacent to the site at Hunterston to switch electricity from AC to DC (or vice versa depending on the direction of operation) for onwards transmission of electricity by two underground AC cables, approximately 500m in length.

Siemens is responsible for construction of the converter station.

A computer-generated flyover of the construction of the converter station

Work planned in 2018

Further work at Hunterston is required to enable the link to operate at its full capacity of 2,200 MW. We plan to complete this during the year.

Work completed in 2017

We completed the majority of work to allow us to commission the converter station and operate the link at up to 900 MW. We also started landscaping the site, where we will be planting more than 25,000 trees and shrubs.

Work completed in 2016

During 2016 we installed most of the equipment within the buildings. This is a significant task as, because of the potential for inclement weather in the area, the vast majority of equipment is housed inside for protection.

Work to the end of 2015

During the year we installed the transformers and other large electrical equipment, which were brought from the jetty by the wind turbine test facility to site by a specialist transport company. We also completed construction of the main buildings, which means we can carry out work inside whatever the weather.

Work to the end of 2014

Planning permission for the converter station was granted by North Ayrshire Council on 13 March 2013. 

Construction of the converter station is being carried out by Siemens, and began in autumn 2013. During this year we established the five-hectare ‘platform’ on which we will build the converter station, cutting it from the hillside rock and reusing this to minimise the amount of materials being transported to site.

We also made good progress on constructing the buildings that will house the majority of the electrical equipment.

Ayrshire cable

We have laid approximately 4km of underground DC cable from the new converter station south to a landfall at Ardneil Bay, where the marine cables come ashore, and completed reinstatement of the land in this area.

A Scottish Hydro Electric project to reinforce the 132kV transmission network on Kintyre, which included laying a subsea cable to Ardneil Bay and then underground cables to the new Hunterston North substation, is complete.

Work planned in 2018

We will complete any work agreed with North Ayrshire Council to reinstate the local roads used while construction was underway.

Work completed in 2017

We pulled the marine cables through the pipes to our temporary compound at Portencross Road, where we joined them to the land cables. When this was complete, we removed the hard standing at the compound and reinstated the land.

Work in 2015 and 2016

During these two years, we completed pulling both pipes from the barge to our temporary compound. We also completed installation of the underground land cables and reinstated the majority of the land.

Work to the end of 2014

To construct the cable, we established a temporary ‘working corridor’, around 30m wide, which we fenced off. The corridor runs from our temporary compound off Portencross Road in a northerly direction towards the converter station, over Thirdpart Holdings Road and across the fields towards Goldenberry Hill. It is wider than the corridor we’re using to install the underground cable on the Wirral peninsula, as it will also accommodate some preparation work for the Kintyre-Hunterston cable.  

Within this corridor we are installing two cables in a single trench approximately 1.2m deep and 750mm wide. The cables are being laid in sections of approximately 1km, with joints where the sections meet. The corridor is also being used to store material excavated from the trench dug for the cable and to install drainage and a temporary road for the delivery of the cable, which arrives on large drums.

By the end of 2014 we had laid the first few sections of the underground cable.

Joining the marine cable to the land cable is a very complex operation, and first needs pipes to be installed which will enclose the cables. Using a technique known as horizontal directional drilling (HDD) we drilled from our compound, under Portencross Road and West Kilbride Golf Course and out to a landing point in Ardneil Bay.

At the end of 2014, we started installing the first of two 600-metre long plastic pipes through the drill hole we had created, pulling the pipe from a barge moored offshore. 

The community

Community Liaison Group

We’ve tried to minimise disruption to local communities during our work at Hunterston. So we could keep local people informed we set up a Community Liaison Group (CLG), to which we invited representatives from community councils, North Ayrshire Council, local businesses and other stakeholder groups. The group meets regularly with our project team.

The group discusses any issues that have arisen relating to construction work, such as traffic management, project timescales and noise. The group also considers any proposals that are put forward by charities or community representatives that will have a positive impact on the local community. Minutes from the CLG are uploaded here within six weeks of the latest meeting.

The members of the CLG are responsible for updating their local communities with information from the meetings and for passing information back to the project team if any issues and queries have been raised within the communities.

If you have any questions for the project team you can contact your local representative or get in touch with our Community Relations Team directly – all contact details can be found here


We have carried out archaeological work in support of the construction of the Hunterston converter station, the Hunterston East substation and the associated infrastructure. On 25 March 2015 we held a presentation on the initial findings of these archaeological excavations. The presentation, the information panels on display at this presentation and a leaflet giving more information on the work can be found on our documents page.

During 2016 we held two further presentations, to the Society of Antiquaries of Scotland and Glasgow Archaeological Society.


On Wednesday 27 November 2013 and on Wednesday 25 February 2015, we held public information events to update people on what is happening on the project.

All the information panels on display at the events and at the archaeology presentation, together with newsletters relating to the project, a leaflet on the archaeology, and more general technical documents relating to the converter station and cable, are on our documents page.   

Fly-over video