In order to provide the required increase of capacity, it is proposed to replace the existing 132kV overhead line between Inveraray switching station to Crossaig substation with a 275kV overhead line. It is intended that the new line will be initially operated at 132kV but with capacity to operate at 275kV, and so it is being constructed as being 275kV capable.

The main elements of the project are as follows:

• Connection to the existing switching station in Inveraray 
• Construction of a new overhead line capable of operating at 132 kV or 275 kV between Inveraray and Crossaig
• Decommissioning andremoval of the existing 132 kV transmission line between Inveraray and Crossaig; and
• Connection to the 132 kV substation at Crossaig

Since the public introduction of the project in 2014, we have been working with a multi disciplinary team of consultants to identify a corridor within which a new overhead line could be routed. Public exhibitions were held in March 2016 to consult with interested parties on the proposed route corridor.

The existing overhead line runs from Inveraray switching station to the new substation at Crossaig and is approximately 83km in length.

It runs easterly through Mid Argyll, adjacent to Loch Fyne and into the Kintyre Peninsula. The line passes through or in close proximity to areas such as Minard, Port Ann, Lochgilphead, Inverneil and Tarbert. Past Tarbert the line is further inland, passing through Whitehouse and ending at Crossaig.

The proposed route corridor that has been identified is adjacent to the existing line in many areas. In defining the proposed route corridor, we considered potential impacts to properties, settlements and other environmental factors. In some locations, the proposed route corridor deviates from the alignment of the existing line to minimise potential impacts on these receptors where possible.

Within that corridor, we are currently working to identify a preferred route alignment. This will include an aerial survey of the proposed route corridor which will aid with the detailed design of the project. With this survey data, the team will begin the next phase of design which will include placement of towers for the new overhead line.

In addition to the aerial survey, there will be ground level surveys taking place to establish the access requirements to accommodate the construction phase of the project. Consultation on the preferred route alignment will be finalised and an accompanying Environmental Impact Assessment and an application under Section 37 of the Electricity Act 1989 will be submitted to the Scottish Government Local Energy and Consents.

The current transmission infrastructure has developed over many years; originally it was built to connect the demand centres that are spread around the north of Scotland and the remote  the remote  multiple hydro electric power stations developed mainly in the 1950s and 60s. However, with the recent increase in renewable generation, in particular wind generation, the pattern of electricity supply and consumption has changed dramatically. As a consequence parts of the transmission network now need substantial upgrading as we seek to meet our licence obligations to develop and maintain an economic, efficient and coordinated system as well as ensuring security of supply to electricity consumers.

Following detailed analysis of required system transfers and comparing this with actual network capacity, we have identified the need to upgrade the transmission network between Inveraray switching station and Crossaig substation.

The need to upgrade the network between Inveraray and Crossaig is reviewed by our transmission business and National Grid (in its role as Great Britain system operator) on an annual basis, and the anticipated timing of the Project may change in response to changing economic signals from a range of electricity generation and demand scenarios.

We have an obligation to respond to the demand for connections that are contracted to connect to the electricity transmission network or that are forecasted to connect. The generation market is kept under annual review. If a developer has a contracted connection date, we must work to that date until the developer modifies its connection application or withdraws it. For these projects, our transmission business and National Grid as transmission system operator are monitoring the activities and progress of many renewable developments including onshore and offshore wind, hydro, pumped storage, wave, tidal, solar and existing generation plant that may increase or decrease their contracted output to the grid. 

Construction of the new overhead line will take approximately three years and during that time the existing overhead line must remain operational to provide power to customers.. Therefore it is not possible to build over the existing overhead line which at a minimum must be kept 50m away to meet operational regulations.

There will be places where the new line must cross the existing line; however the timeframes will be kept to a minimum and contingency plans shall be put in place to overcome the technical challenges.

As a responsible developer, we believe that it is important to seek public opinion on our proposals and take that feedback into consideration when developing their projects. Consultation events are therefore held at defined stages of project development in various locations along the route of the proposed line. These consultation events are widely publicised in order to ensure that as many people as possible are made aware of them. 

Prior to consultations held in March 2016 on the preferred route corridor, the services of a mailing company were utilised to mail drop over 10,000 information notices to houses in local postcodes. Elected members and Community Councils also received information notifications via post. The events were advertised in the local newspapers and posters were placed throughout the local communities. The events were also advertised via our social media platforms and on our dedicated project webpage.

A similar approach will be adopted to ensure the effective publicising of future consultation events