Great British Energy – Nuclear (GBE-N) and Rolls‑Royce SMR have signed a contract to deliver the UK’s first three small modular reactors (SMRs) at Wylfa – an island off the coast of North Wales.

In June 2025, the UK government confirmed that it had selected Rolls-Royce SMR as the preferred bidder to partner with GBE-N on SMR plants, alongside a further £2.5bn in funding. The move forms part of what energy secretary Ed Miliband called the “golden age” of nuclear energy. 

In November 2025 it was announced that Wylfa would host the UK’s first SMR power plant, subject to final government approval. This approval has now been granted and the contract has been signed. Work to construct the initial three SMR designs on site will now start, which will include ordering critical components from its UK supply chain.

According to Rolls-Royce SMR, the project is estimated to support around 3,000 jobs at peak construction and thousands more across the supply chain.

Simon Bowen, chair of GBE-N, said: “Today represents a true recognition of the efforts made across GBE-N, Rolls-Royce SMR and government to get to this point, and I’m hugely proud of the team for reaching this critical milestone.”

Miliband said: “At a time of global instability, this is a major milestone for Britain’s energy security. Our clean energy mission is the only route to getting off the rollercoaster of fossil fuels and take back control of our energy independence.”

Unlike large nuclear power plants, which take a lot of investment and a lot of time to build (sometimes a decade or more), SMRs are built in a factory as modular components. These modules are then transported to and assembled on-site, radically reducing construction time.

The Rolls-Royce SMR is based on a compact, three-loop pressurised water reactor designed to generate approximately 470MW of electrical power, enough to power one million average households, or a city the size of Sheffield, for at least 60 years.

Another advantage is that SMRs can be scaled up for larger demand. The site at Wylfa will initially host three SMR units, but GBE-N says it has the capacity to host up to eight. The ambition is for Wylfa’s three SMRs to be supplying power to the grid from the mid-2030s.

Chris Cholerton, chief executive of Rolls-Royce SMR, said: “We are transforming the way nuclear projects are delivered, to give greater cost and schedule certainty with a standardised, factory-built approach. This project is important to the UK’s energy security and will power up our business and the UK supply chain, and we are excited by the opportunity and are focused on successful delivery.”

The latest video in our E+T Expert Engineering series explores SMRs and why miniaturising nuclear technology may prove that smaller is indeed better. Watch it below: