SSE plc [LON: SSE]
Expanding Grid Capacity without Compromising Reliability

Scotland’s renewable electricity generation is growing, but much of it is concentrated far from major demand centres. Limited transmission capacity can prevent this power from reaching where it is needed, forcing generators to reduce output. At the same time, rising electricity demand from electric vehicles and heat pumps is placing greater pressure on local distribution networks. Expanding grid capacity while maintaining a reliable electricity supply has become a critical infrastructure priority.

SSE plc [LON: SSE] operates at the intersection of Great Britain's renewable electricity ambitions and the physical limitations of the grid.

It develops major high-voltage transmission connections to transport renewable electricity from northern Scotland to key demand centres, while strengthening local distribution networks through flexible capacity arrangements and digital services that support evolving electricity needs. Its approach combines large-scale infrastructure development with more efficient use of existing networks, helping reduce grid constraints, expand capacity and maintain a reliable electricity supply as demand grows.

Scottish and Southern Electricity Networks Transmission (SSEN Transmission), a subsidiary of SSE, maintains 132kV, 220kV, 275kV and 400kV infrastructure across the north of Scotland. Its license area covers roughly a quarter of the UK's landmass but has less than five per cent of its population. That imbalance makes exporting renewable electricity to other regions a defining requirement of its network development.

Its plan for the RIIO-T3 period sets out over 29 billion pounds in network investment through the end of the decade, covering 11 major projects. Five were in construction by April 2026, and over three-quarters of the required consents had been secured.

The program combines five offshore reinforcements with six onshore schemes. One is Eastern Green Link 2, developed with National Grid Electricity Transmission. The 4.3 billion pound project will use a 505-kilometre high-voltage direct-current subsea cable between Peterhead and Drax, with 2GW of transfer capability. Converter station construction has advanced at both ends, while cable installation remains ahead in the project schedule.

Another is the Orkney Link, designed to connect Orkney to Great Britain's high-voltage transmission system for the first time. It pairs substations at Finstown and Dounreay with a 53-kilometre subsea cable. At the Orkney landfall, crews completed two 1,200-meter horizontal directional bores, preparing a route beneath the shoreline for the future connection.

Balancing Capacity on Local Networks

Scottish and Southern Electricity Networks Distribution (SSEN Distribution), a wholly owned subsidiary business of SSE, manages the local electricity networks that deliver power to homes and businesses. It supplies more than 3.9 million homes and businesses through over 128,000 kilometres of lines and cables and more than 106,000 substations. The work concerns how to accommodate new demand without waiting for every local circuit to be physically enlarged.

Flexibility services give a way to adjust when electricity is consumed or exported in constrained areas. Depending on network requirements, constraints are managed by drawing on stored power, additional generation or temporary reductions in electricity demand.

In November 2025, SSEN Distribution began piloting day-ahead flexibility markets through ElectronConnect, a digital platform developed by UK energy technology company Electron. Energy providers can use the platform to offer additional electricity or reduce consumption the following day when local networks face capacity constraints. This gives SSE greater flexibility to manage demand while allowing participating providers to earn revenue for supporting the network. By October 2026, it had procured more than 1,039MW of flexibility during its current ED2 price-control period.

Making Connections Easier to Plan

Faster connections depend on what applicants can establish before speaking to an engineer. SSE’s Self-Serve Connections platform allows users to identify their property on a map using a postcode, simplifying the initial steps of the electricity connection process. They can identify cable routes, meter positions and intended equipment to receive an initial cost estimate. By September 2026, more than 11,000 people had used the tool to generate around 4,500 estimates, over half of which progressed to formal quotations.

Where a property requires an engineering assessment, a separate smart-video process addresses the site survey. Customers capture guided smartphone footage showing the areas where equipment or cables may be installed. AI-supported analysis gives SSEN Distribution's specialists material to review before work begins, reducing preliminary visits while retaining an in-person option.

SSE’s NeRDA service helps developers and public authorities make informed decisions about where to plan new projects and connect them to the grid. It provides near-real-time data from nearly 9,000 smaller substations, covering around eight million indicators. The service helps users assess potential sites and connection requirements using current data rather than outdated network information.

Keeping Power Moving during Major Works
Building and upgrading transmission infrastructure requires maintaining a reliable electricity supply throughout construction. At Fetteresso in Aberdeenshire, SSEN Transmission is upgrading a 275kV substation to 400kV. Temporary bypass arrangements keep key 275kV circuits between Kintore, Fetteresso and Alyth available during construction, helping preserve the grid's ability to move power.

The decision also helps control costs. When transmission networks cannot carry all the electricity being generated, power producers may have to reduce their output, adding costs to the system. Through its broader efforts to ease these constraints under the System Operator Transmission Owner Optimisation incentive, SSEN Transmission helped deliver 296 million pounds in consumer savings during 2025–26.

Past delivery offers a benchmark for the next phase. SSE completed the Shetland high-voltage direct-current link ahead of schedule, within budget and without a construction-related accident. By March 2026, 10.8GW of renewable generation capacity was connected within SSEN Transmission's area, showing the existing system's role before the newest reinforcements are finished.

Reliability Built into Delivery

For remote communities that rely on a single cable for electricity, maintaining a dependable connection is important. In February 2026, SSEN Distribution announced a framework worth up to 950 million pounds with five specialist contractors to renew subsea links serving Scottish islands. Working with five specialist contractors, it plans to renew subsea cables serving the Scottish islands, strengthening the reliability of electricity supply while preparing these networks for growing demand.

SSEN Distribution is also exploring how shifting electricity use during planned maintenance can help maintain a reliable power supply, as well as reduce reliance on temporary diesel generators and minimise the risk of outages.

SSE is backing its infrastructure expansion with substantial investment. The company invested 3.6 billion pounds in 2025–26 as part of a broader 33 billion pound five-year program extending to 2030. Investment across its network businesses reached 0.9 billion pounds in the first quarter of 2026–27, up 83 per cent from the previous year, reflecting the pace of its transmission projects and preparations to strengthen local distribution networks.

SSE’s recognition as the Top Electricity Transmission and Distribution Services in Europe 2026 underscores its ability to expand grid capacity, strengthen reliability and address network constraints.