The Hinkley Connection Project from National Grid PLC - 400 kV upgrade reshapes UK power flows

Reviewed: ad hoc news Classics & Longseller desk. Edited and checked on 2026-06-28, 14:24. Details in the imprint.

The Hinkley Connection Project from National Grid PLC cuts across quiet Somerset fields, a line of new T-pylons marching between hedgerows and grazing sheep as crews bolt pale-grey steel in the wind. This long-distance upgrade is built to carry nuclear-generated low-carbon power. It is one of those projects people only notice once it is switched on and humming.

What the project delivers

The Hinkley Connection Project is a major 400 kV electricity transmission line linking Hinkley Point C to the Seabank substation near Avonmouth, strengthening the south-west section of the UK grid. It spans around 57 km and replaces some older 132 kV infrastructure along the route. For local residents, that means new structures but fewer separate lines.

National Grid says the project will be able to move up to 6 million homes' worth of electricity generated by Hinkley Point C once the station is operational, turning this corridor into a core route for low-carbon baseload power. On the official project overview, the company highlights that this connection is critical to meeting UK decarbonisation and security-of-supply targets.

T-pylons and design choices

The most visible change with the Hinkley Connection Project is the introduction of so-called T-pylons, a new transmission tower design that National Grid developed with architects and engineers to reduce visual impact and land-take. Each structure stands about 35 metres tall, meaning they are shorter than traditional lattice pylons and present a more compact profile on the horizon.

Engineers route lines over a single "T" cross-arm instead of a wide metal frame, which removes some of the skeletal complexity familiar from older towers. Project director James Goodyear has described walking under a newly erected T-pylon as feeling more "tidy" and less looming than with the web of steel from legacy designs, even though the voltage rating is higher.

How construction feels on the ground

Construction teams have been working in sections, using tracked vehicles that leave deep, temporary prints in wet soil as they bring crane parts and concrete to each site. For nearby residents, much of the noise comes in pulses: a burst of drilling, the metallic ring of bolts being tightened, then quiet again while crews move to the next span.

National Grid says it has removed sections of older 132 kV lines and is undergrounding parts of the route nearer to the Mendip Hills Area of Outstanding Natural Beauty to reduce landscape intrusion. On local consultation documents, the company outlines mitigation measures like timing heavy works outside nesting seasons and providing compensation where land use changes.

Regulation, returns and risk

From an investor perspective, the Hinkley Connection Project sits inside National Grid's regulated UK electricity transmission business, where spending is reviewed by Ofgem and allowed revenues are set over multi-year periods. In its capital markets materials, National Grid breaks out a multi-billion-pound investment plan that includes Hinkley as part of a wider push to connect low-carbon generation.

The cost base for the connection feeds into the regulated asset value, which in turn drives allowed earnings under Ofgem's price control model. That gives a fairly predictable cash-flow profile once the asset is in service, though the company still faces scrutiny on efficiency and on how well it manages community concerns around new lines.

Community response and compromises

Consultation rounds for Hinkley Connection have brought mixed reactions, with some residents welcoming the removal of older lines and the use of shorter T-pylons, while others criticise the continued presence of tall structures across open countryside. At village halls, you can picture farmers like John Harris tracing the route on a laminated map, weighing compensation against the view from his kitchen window.

National Grid has argued that full undergrounding over the entire length would be far more expensive and complex, particularly across varied geology and multiple crossings. Instead, the company presents the T-pylon design and selected underground sections as a compromise that balances cost, reliability and visual impact, with Ofgem and government looking at overall system needs.

Timeline and next milestones

The project has been in development for more than a decade, with route selection, planning and community engagement starting soon after the Hinkley Point C nuclear project itself was confirmed. National Grid's latest updates indicate that most T-pylons along the route have now been erected and that stringing of the conductors is progressing section by section ahead of full energisation.

On its dedicated project page, the company sets out a phased commissioning timetable aligned with Hinkley Point C's own schedule, emphasising that the connection must be ready before the first reactor feeds power into the grid. That adds schedule pressure, but also underlines how central this line is to the UK's long-term decarbonisation plans.

Company context and shares

National Grid PLC positions the Hinkley Connection Project alongside other large UK and US transmission investments as it retools its portfolio for more renewable and nuclear integration. The company has been reshaping its asset mix, including deals to focus more heavily on electricity infrastructure.

National Grid PLC shares (ISIN GB00BDR05C01) trade on the London Stock Exchange, with recent data from broker Davy showing a last price of around 1,245.50 pence on 28 June 2026 after a modest daily move. For holders, long-lived regulated projects such as Hinkley Connection help underpin the earnings story over decades.

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