In episode 4, we'll discuss the ambitions and challenges of the UK energy transition.

These ambitions could see the UK's nuclear sector develop up to eight new reactors, including large-scale nuclear power plants and small modular reactors. SMRs are a nuclear technology that we have discussed before on Switch On and they will play a key role in the UK’s energy transition ambitions. Plans are also underway for the UK to commission and build a prototype fusion energy reactor which aims to demonstrate the commercial viability of the technology.

The UK is well-placed to lead the development of commercial fusion technology and influence global markets, if a robust regulatory framework is established. Want to know more? Listen to this episode of our Switch On podcast.

What are the energy transition ambitions and challenges in the UK?

The United Kingdom, the first major economy to legislate the "Net Zero" emissions target by 2050, published its Net Zero strategy in 2021, followed by the energy security strategy in early 2022. The objective? To achieve energy independence by providing up to 50 gigawatts of offshore wind, 10 gigawatts of hydrogen by 2030, and up to 24 gigawatts of additional nuclear energy by 2050.

Ambitions, means and milestones. In our latest episode, Assystem’s UK Managing Director Simon Barber decodes the details of the UK’s energy transition policies.

A clear framework for action, an ambitious policy

"The net-zero strategy and energy security strategy provide the UK with a clear policy framework to fulfil its mission, which is key to its success,” says Simon.

To reach its goal, the UK's government intends to use two levers: accelerate the development of new technologies and build on the foundations already put in place for technologies such as offshore wind, which has become something of a national success story.

However, nuclear energy must remain as the cornerstone of the UK’s energy transition, to meet its requirements for mass-produced, low-carbon electricity. "The UK's ambition is that by 2050, a quarter of the electricity consumed in the UK comes from nuclear power," says Simon, "that's up to 24 gigawatts of new nuclear power plants on the grid by 2050—three times more than what we have today."

The UK’s hydrogen agenda will be equally ambitious; its goal is to produce ten gigawatts of hydrogen by 2030. Combined with its plan published in 2019, which aims to decarbonise rail, maritime, and road transport - via a transition to electric vehicles and its jet-zero aviation strategy - and details of the challenges and opportunities associated with this topic that accompany this issue, the United Kingdom has a very comprehensive energy security policy based on renewable sources. The only downside is that this policy is silent on electricity networks: "This is crucial for transporting and transporting electricity and hydrogen production to end consumers," says Simon.

Nuclear power, the basis of the energy security strategy

The UK's ambitions could stretch to the development of up to eight new high-power reactors, something Simon Barber says should be front-and-centre in the UK’s energy transition ambitions: "For the British government, the policy to guarantee energy independence while promoting a low-carbon strategy must be based first and foremost on nuclear power, which has proven its worth in the United Kingdom."

The UK is also expected to build and commission a prototype fusion energy plant, STEP, which aims to demonstrate the commercial viability of this technology. "The UK would then be well-placed to lead the industrial development of fusion technology and influence global markets, provided a sound regulatory framework is established," says Simon.

In July 2023, the UK government announced the formation of Great British Nuclear, an organisation designed to aid the development of large-scale reactors, such as Hinkley Point C and Sizewell C, while guiding the delivery of small modular reactors (SMRs) and advanced modular reactors (AMRs), which offer a more compact, batch-production approach to nuclear power – a novel solution for the UK’s small size and high population density. "For large-scale nuclear, only a small number of sites are suitable,” Says Simon, “SMRs could provide access to more sites, especially those that have historically produced nuclear energy, but are insufficient to install large-scale power plants." Rolls-Royce, one of the leading developers of SMR technology in the UK, is particularly interested in these sites. Rolls-Royce initiated a design phase to develop SMRs in the UK, with funding from government and partner organisations, such as Assystem. Once approved for production, Rolls-Royce aims to attract private developers and move into a deployment phase by 2029. "SMRs could position the UK as a potential exporter of leading technology with Rolls-Royce's deployment of technology subject to the UK's regulatory approval process," Simon said.

"Because of their small size, SMRs offer an opportunity to access more sites and achieve the objectives set . "

Hydrogen, distribution networks... New challenges ahead

Hydrogen as an energy carrier will also be a key component of the energy mix. The United Kingdom is formalising a strategy to address all aspects of low-carbon hydrogen, from exploration to transport and storage. The greatest challenges will not lie in skills – the UK offers a range of transferable skills from its oil and gas sector – but in how hydrogen will be integrated into its power, production, and transport infrastructure. Will it be possible to use the current national gas transport system and if so, how? The skills and innovations required are linked to other areas of the UK’s energy transition challenge, says Simon. "More broadly, the proposed energy strategy will pose challenges associated with the transmission and distribution of electricity. It will require a quite different network system, again, with significant investment needs. "

"Almost all of our infrastructure will need to change over the next 30 years. So, it is a huge challenge. When you move away from what we've traditionally had in the UK, which is large coal and gas plants, a highly centralised distribution grid for electricity, and you move to renewables, offshore wind, then you need a very different grid system."

Transport at the heart of the strategy

Transport accounts for 25% of the UK's total emissions, making it the country’s largest emitting sector. Implementing the United Kingdom's commitments, therefore, requires action in all areas of transport. This means accelerating electrification through the deployment of electric vehicles and the associated charging infrastructure. Hydrogen could play a key role in this decarbonisation, through the electrification of trains and as a potential source of fuel for buses and trucks.

"At Assystem, we play an active role on these topics. For example, we are heavily involved in the conversion to hydrogen for public transport networks or trains."

What are the conditions for a successful energy transition?

The first condition is to develop the right skills. Within Assystem, this subject is fully considered. For example, the Group has committed to integrating one hundred women engineering graduates by 2025 to work on Hinkley Point C. It has also launched a strategy to equip engineers and technicians with the knowledge and capabilities necessary to commission new power plants. "Assystem has a role to play as a major player in the industry to close this skills gap and start investing now," says Simon.

The other challenge concerns digital, a key success factor in the realisation of all these complex projects. Having proven its ability to reduce resource requirements of projects by up to 30%, digital solutions serve as a major asset to strengthen connectivity and collaboration between teams on an international scale. Naturally, Assystem has made digital solutions a lever for progress across its international entities: "In this way, the Indian company Stup acquired in 2021 will be able to contribute to the realisation of British programmes."


Discover some of our projects in nuclear in the UK :


Simon Barber

Simon Barber

UK Managing Director at Assystem

Simon Barber has over 27 years of experience in the UK nuclear sector working across new build, defence and grids. Simon became Assystem’s UK Managing Director in 2020, bringing his depth of knowledge in the UK nuclear sector to the group in order to support the acceleration of the British energy transition.


In Switch On, our engineering, digital and project management experts shed light on the projects and technologies that are contributing to the energy transition around the world today.


S1 - Episode 3 | Will SMR projects be a game changer?


S1 - Episode 5 | Hydrogen: a revolution in progress for the energy transition?


S1 - Episode 1 | Accelerating nuclear development around the world through digital