ScottishPower has received approval from the UK energy regulator, Ofgem, for a historic investment programme of up to £12 billion aimed at transforming the electricity transmission network across Central and Southern Scotland.

This major undertaking falls under Ofgem's RIIO-T3 Final Determination regulatory period, running from 2026 to 2031.

This represents a record level of investment by ScottishPower in a comprehensive grid rewiring programme, designed to enhance network resilience, unlock capacity, and promote economic growth in Scotland. The investment is anticipated to deliver a sustained economic benefit to the UK's GDP of approximately £2 billion per year.

With Britain's electricity demand expected to double by 2050, this modernisation is critical for creating a modern, flexible, and greener energy system.

The work, managed by ScottishPower's SP Energy Networks business, includes:

- Building 12 new major substations.

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- Upgrading 450km of existing circuits.

- Reconducting 87km of overhead lines.

- Replacing 35km of underground cable.

Crucially, the investment also covers two multi-billion-pound subsea electrical superhighways off the East Coast of Scotland: the Eastern Green Link 1 (EGL1) and Eastern Green Link 4 (EGL4). These high-voltage lines will have a combined capacity of 4GW and a total subsea cable length of 706km.

The ambitious infrastructure build-out will necessitate a major workforce expansion. As the transmission owner for the region, SP Energy Networks plans to double its direct workforce by recruiting 1,400 new roles and supporting an additional 11,000 jobs across the country.

While the investment is projected to add around £12.07 per year to a customer's bill (an increase of £6.47), the long-term savings are substantial. The total transmission investment across the UK is estimated to reduce "constraint costs"—the expense of turning off generators when power cannot be transported—by approximately £5 billion per year, potentially saving consumers up to £167 per bill annually by 2030.

Nicola Connelly, CEO of SP Energy Networks, welcomed the decision: "We welcome Ofgem's final determination recognising the need for this historic investment in critical network infrastructure. Our record investment of almost £12bn will unlock capacity in the grid and bring economic growth across our area of central and southern Scotland and beyond. Whilst also bringing costs down for consumers by reducing network constraints."

She concluded that making this crucial investment now will "drive a positive impact on stabilising and lowering consumer energy bills in the longer term. And it will achieve the UK's ambition to be a clean energy superpower, enhancing the security and resilience of our energy supplies."