View from the top: Stéphane Aubarbier, Deputy CEO, Assystem

At the Top: Stéphane Aubarbier

Stéphane Aubarbier, an INSA Lyon and ESCP-EAP graduate, began his career at Assystem as a commissioning engineer, later leading its automotive sector. After five years at ABB managing maintenance and service activities across Southern Europe, he returned to Assystem in 2002 to create its engineering activities and redevelop its energy and nuclear sector. He became Executive Vice President in 2005, Chief Operating Officer in 2018 and Deputy CEO in 2023, overseeing all operations. He has presided over the French federation Syntec-Ingénierie and serves on the French Nuclear Industry Strategic Committee.

Assystem describes itself as an activist in nuclear energy development. What does it mean by this, and why is activism important to you?

We believe nuclear energy will be the cornerstone of the effort to decarbonise global electricity generation. It is the only energy solution that can replace fossil fuels with low-carbon energy production while satisfying base-load electrical demand.Assystem’s mission is to step up the energy transition throughout the world, and in this regard, we consider ourselves activists in the fight against climate change. We put all our energy into this, coupling our historical engineering expertise and project management with digital technologies to ensure a viable, efficient and reliable energy future for all.

With 59 years of experience, how has Assystem changed as a business, and what have been its key milestones or transformations along the way?

Assystem’s nearly 60-year journey reflects the shifting global energy landscape – from France’s 1960s nuclear boom to the global diversification that saw the group working in automotive and aerospace in the 2000s, re-focusing on nuclear in 2017. Our milestone moments have been when we have correctly anticipated an emergent trend or shift; refocusing on nuclear was one such move. In addition, our ability to transform and strengthen our offer, focusing on digital at the right time and then project management, has allowed us to deliver more for customers – particularly relevant now, when resources in the nuclear marketplace are stretched.

Assystem’s mission is to step up the energy transition throughout the world, and in this regard, we consider ourselves to be activists in the fight against climate change

What does being ranked among the nuclear energy sector’s top three companies mean for you and your stakeholders?

We have been able to secure our position because of our unrivalled expertise as an independent global nuclear engineering company. Among our competitors, we are the only company that is completely focused on the nuclear and energy transition sectors.

Assystem operates across a range of energy sectors. How do these sectors complement each other in your strategy for supporting the global energy transition?

Our experts work globally on the development of low-carbon electricity, in terms of both production and distribution, through the expansion of nuclear and renewable energies throughout the world. We also focus on renovating power grids and developing new uses for electricity, such as decarbonising transport and industry through hydrogen.

Innovation is critical to meeting both performance and sustainability goals. How important are digital, data and AI to the future of the business?

As an industry leader in digital for complex projects, we consider digital technology key to accelerating nuclear power programme delivery. By bringing greater efficiency in delivering these infrastructure projects, digital technology will reduce nuclear power timescales – helping to attract new financing models and new customers to the market.

Assystem is partnering with Rolls-Royce on the development of SMRs

How important is collaboration to your success, and what have you learned about what makes a strong and effective partnership?

Given the scale and complexity of our projects, from nuclear power plants to energy transition infrastructure, no entity can succeed in isolation. In our experience, there are two key elements needed for a successful partnership, starting with mutual trust, transparency and cultural fit. We’ve learned that transparent communication – especially around risks and challenges – builds long-term trust, which allows for faster problem-solving and more resilient project teams. We always deliver the project awarded to us, but our approach is to see the big picture and be ready to step in and deliver in other areas to achieve a positive result for the customer. Our most effective partnerships are founded on a mutual commitment to securing success for the customer over individual company gain.

Second, it is about identifying the best capability in the right place at the right time. Part of our strategy is to work with local companies to deliver international projects. This transfers skills to local people, which improves long-term project sustainability and enables access to local supply chains, offerinf better value for materials and resources – and, in turn, improving long-term customer outcomes.

Digital technology is key to accelerating nuclear power programme delivery

There has been a lot of talk about different solutions to power the data centre boom recently. What role do you see for nuclear in this space?

Nuclear power is attractive for energy intensive industries as it offers a stable source of low-carbon electricity that, in the case of small modular reactors (SMRs), can be positioned next to industrial energy consumers and work off-grid.

Hyperscalers have already identified nuclear as a key power source in meeting their needs, as data centre demand becomes more urgent due to widespread AI adoption in our day-to-day systems. Nvidia is investing in SMR technology such as TerraPower to power data centres, and developers such as the UK’s Community Nuclear Power seek to place SMR technology at the centre of their industry-focused power projects.

Large-scale nuclear also has a role to play, and the Microsoft-financed planned restarts of nuclear plants such as Palisades in Michigan and Three Mile Island Unit 1 are examples of this in action. The challenge for the nuclear industry will be to deliver the power plants at the pace required to meet demand from this industry.

Powering progress in fusion and fission. Left: Assystem supporting engineering and safety systems at ITER. Below: Assystem delivering project management and design services for Sizewell C

What is your view on the future of nuclear SMRs, and when do you expect this technology to move from pilot to scale?

Assystem explicitly identifies SMRs and advanced modular reactors (AMRs) as essential technologies to accelerate the global energy transition, and we are currently supporting multiple developers on their projects, including Rolls-Royce SMR, Newcleo and Naarea.

There are two timescales for SMR development. The first relates to existing and/or proven technology for large-scale nuclear that has been made smaller. Technology such as the Rolls-Royce SMR is of this type, deriving from the pressurised water reactor design used for decades in conventional reactors worldwide. We can expect to see these reactors available in the short term, in response to a clear demand on the market.

The second timescale concerns new technologies such as AMRs, which go beyond traditional water-cooled designs, incorporating innovative coolants like helium, molten salt and liquid metals, which can improve efficiency and reduce waste. Some companies, such as Newcleo, have already submitted applications for Generic Design Assessment, a crucial step in the regulatory process for new reactor designs. However, as new technologies, AMRs are not expected to be widely available until the mid-2030s. 

A signing of a Memorandum of Understanding with Assystem’s entity in Uzbekistan, UzAssystem, and Uzbekistan’s Ministry of Energy. L-R: Laziz Kudratov, Minister of Investment, Industry and Trade, Umid Mamadaminov, Deputy Minister of Energy, Nicolas Dugot,

What are the main challenges to growing the nuclear industry right now?

Nuclear remains highly capital-intensive, and the cost of capital and perceived risks continue to deter private-sector investment. New finance models such as the Regulated Asset Base (RAB) will be essential to unlock institutional capital; the Sizewell C capital structure is backed by the RAB funding model. If standardised and made repeatable, SMRs could reduce scale risk and attract new funding sources. Public-private partnerships, tech-sector power purchase agreements and multilateral backing are emerging as critical enablers of nuclear scale-up.

Do you think critical nuclear capabilities need to be developed in the UK, or is it more pragmatic to build strong trading and technology relationships with other countries that already have that technology?

Our delivery model in every country in which we operate is to invest in developing local capabilities. This is core to our strategy and delivers multiple benefits for customers, decades after their projects have been completed. We have even taken this approach in the UK, which has a strong nuclear heritage and supply chain, because it has been three decades since nuclear power was constructed in the country and many skills are in short supply. In recent years we have taken an active role in supporting knowledge transfer on the European Pressurised Reactor (EPR) programme at Hinkley Point C with commissioning experts from France who bring unrivalled knowledge from commissioning the Olkiluoto EPR in Finland. To support the successful delivery of Hinkley Point C and Sizewell C, we have also invested £45m since 2020 in acquiring specialist companies operating outside nuclear that add value to nuclear delivery, to secure the UK’s nuclear workforce in the long-term.

What strategic priorities or global markets are top of mind for Assystem as the energy transition accelerates?

Our international focus is on countries that are building nuclear power.

If you had one message for governments, industry partners and the next generation of talent about the future of nuclear, what would it be?

When a government commits to nuclear power, it is not just investing in decarbonised electricity – it is investing in its country’s long-term scientific capability, the high-value skills of its people and their energy sovereignty for an entire century. Nuclear is the only energy solution that can replace fossil fuels and provide a stable, low-carbon and abundant supply of electricity to meet energy demand today and in the future. The technology is constantly evolving, and in the 21st century, nuclear fusion will also play a key role is delivering decarbonised electricity.

Image credit | Assystem | Rolls Royce | Hinkley Point C | iStock-Shutterstock