East Coast 275kV Upgrade
- Transmission reinforcement
- Aberdeenshire, Angus, Perth & Kinross
Status: Construction Phase
Stage 4 of 5 complete — This is the stage where we mobilise our people, contractors and equipment. The project is well underway at this point.
About the Project
The East Coast 275kV Upgrade is the first part of the phased onshore reinforcement of the electricity transmission network on the east coast of Scotland. These reinforcements comprise works on existing infrastructure in both ours and Scottish Power Energy Networks (SPEN) area, with the bulk of the works in our area.
The main advantage of a two-stage approach is this allows for earlier delivery of increased capacity on the network in this region. This will also help resolve the issue of overloading and congestion on the transmission network.
The east coast steel lattice towers and the overhead lines which they support are currently operating at 275kV. The projected growth in generation capacity within our area gives rise to increased north to south power transfer requirements and therefore the overhead lines are required to transfer more power. As a result, the conductors will operate at an elevated temperature, which can cause the conductors to sag. As a responsible operator we have modelled the future sag and under this project will undertake works to ensure the conductors remain within a safe clearance height.
The works required are termed as re-profiling works, where works such as vegetation clearance or changing of fittings on some towers to raise the conductor will be undertaken. This will ensure safe clearance between the ground and the conductor is maintained.
Why is the Project Required?
As part of our statutory and transmission licence obligations, we have a number of duties including:
- the development and maintenance of an efficient, coordinated and economical system of electricity transmission
- to facilitate competition in the supply and generation of electricity
- to ensure that the security of the network is maintained as the demand and/or generation connections change over time
We have a licence obligation to invest in our existing assets to maintain network health and condition. We also have a statutory duty under the Electricity Safety, Quality and Continuity Regulations 2002 to ensure that the electricity transmission network is fit for purpose.
The National Electricity Transmission System Security and Quality of Supply Standard (NETS SQSS) provides the deterministic criteria that we must use to plan and design the transmission system. The criteria require that there are neither equipment overloads nor voltage violations under intact conditions. The criteria also require that there is no unacceptable overloading of any primary transmission equipment or unacceptable voltage conditions under planned or unplanned outage conditions.
Throughout the life of our projects, we aim to work positively with local communities and keep people informed about what we are doing. This is particularly important when we are developing a proposal and we want to understand what local people think about our plans.
We endeavour to take the time to discuss proposals with local community councils, encourage engagement from the wider community and listen to the feedback we receive.
We will do our best to answer any questions and address issues or concerns that are raised with us.
When our project progresses into construction, we will continue working closely with the local community to ensure that our work has as little impact on the lives of those living and working in the area and as many long term positive effects as possible.
Project Update - March 2022
Project Update - December 2021
Project Update - August 2021
East Coast 275kV and 400kV Overhead Line Reinforcement Projects Information Booklet - April 2021
- 06 April 2021
- 3.4 MB
North East 400kV and Eastern Reinforcements Information Booklet - November 2019
- 20 November 2019
- 4.5 MB
A selection of photographs taken on site documenting the project construction progress of phase 1 which consists of overhead line works associated with the new Alyth substation that is currently in construction.
It’s the highest voltage electricity network in the UK – the ‘motorway network’ of the energy world. It transmits large quantities of electricity over long distances via wires carried on a system of mainly metal towers (pylons) and large substations. Transmission voltages in Scotland are 132kV, 275kV and 400kV. Larger generation schemes usually connect to the Transmission system.
The lower voltage parts of the system are called distribution networks. In Scotland, these local networks operate below 132kV whereas in England the distribution network includes 132kV.
SSEN Transmission is responsible for maintaining and investing in the electricity transmission network in the north of Scotland and our network extends over a quarter of the UK’s land mass, crossing some of its most challenging terrain.
Our operating area is home to vast renewable energy resources, and this is being harnessed by wind, hydro and marine generation. Working closely with National Grid Electricity System Operator (the 'ESO'), we enable electricity generators to connect to the transmission system, allowing the electricity generated by them to be transported to areas of demand across the country.
Following a minority stake sale which completed in November 2022, SSEN Transmission is now owned 75% by SSE plc and 25% by Ontario Teachers’ Pension Plan Board.
SSE plc sold its UK domestic electricity and gas retail business, along with domestic energy services to OVO Energy in January 2020 and no longer manages these customer accounts.
As a stakeholder-led business, throughout the life of our projects, we aim to work positively with local communities and keep people informed about what we are doing. This is particularly important when we are developing new projects, we want to understand what local people think about our plans.
We always endeavour to take the time to discuss our proposals with local community councils and the wider affected community and to carry out engagement throughout each of the development stages, listening to feedback before finalising project plans. The feedback we receive is vital to help us develop proposals that reflect the views of a variety of stakeholder.
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