EPCs Step Into Fusion Earlier and Why It Matters: 3 Key Insights
EPCs Step Into Fusion Earlier and Why It Matters: 3 Key Insights
Dec 16, 2025
Fusion energy is moving out of the laboratory and into early engineering, even though most fusion companies are still in the design phase. With more than 70 fusion developers now active globally, engineering, procurement and construction (EPC) companies are engaging earlier than in past energy technologies.
At a Technical Discovery Session on 4th December 2025, speakers Lee Patrick (AtkinsRéalis), Lisa Davies (Fluor) and Ulrich Siegel (Focused Energy) discussed why EPC involvement is starting now, what EPCs can realistically contribute at this stage and what still needs to change for fusion to scale.
Here are three key insights from the event.
1. EPCs are engaging early because fusion is becoming a credible long-term market
EPCs are not entering fusion because projects are ready to be built today. They are engaging because the sector has reached a size and momentum that makes early involvement worthwhile.
With dozens of fusion companies pursuing different technical approaches, EPCs see value in understanding the sector early, building relationships and learning where their experience can add value as projects mature. As Lee Patrick (AtkinsRéalis) noted, “fusion is an important part of our portfolio, but a relatively small part at the moment, and that represents the maturity of the sector.”
This early engagement reflects a broader shift in fusion development. More companies are beginning to look beyond physics performance and ask practical questions about cost, timelines and delivery. EPCs are positioning themselves to support that transition, even while designs are still evolving.
2. Involving EPCs early helps avoid designs that are expensive or difficult to build later
Early design decisions strongly influence cost, schedule and whether a project can realistically be built. As Lisa Davies (Fluor) observed, “there is an old adage about beginning with the end in mind” and several panellists stressed that this is particularly relevant for fusion.
Lisa Davies (Fluor) put the point clearly: “The most cost-effective design concepts are provided early in the design. Changes made a year or two after design initiation usually result in rework, cost increases and schedule delays.”
Lee Patrick (AtkinsRéalis) backed this from an EPC perspective: “We need to be getting in now and fixing some of that stuff so we do not bake in difficulties which we need to overcome downstream.”
In practice, EPC involvement today is focused on test facilities, subsystem demonstrators and early plant concepts rather than full power plants. This early input allows developers to consider layout, access, integration and supporting infrastructure while designs are still flexible, reducing the risk of designs that perform well in isolation but are difficult or expensive to deliver at scale.
3. Fusion cannot scale without EPCs but commercial delivery still faces structural challenges
Speakers were clear that EPC involvement will be necessary as fusion moves towards deployment, but first-of-a-kind plants raise challenges that cannot be solved by engineering alone.
One key issue is how risk is handled. As Lee Patrick (AtkinsRéalis) explained, “when you’re delivering first-of-a-kind plants, performance guarantees are a difficult thing to fully transfer. We need flexibility in those contracts.”
Another challenge is how different organisations work together. Fusion developers and large engineering firms often operate in very different ways, which can create friction if it is not addressed early. As Patrick put it, “there’s quite a different culture between fusion start-ups and large engineering organisations, and that’s a real risk area if you get it wrong.”
From the fusion developer side, Ulrich Siegel (Focused Energy) highlighted the wider transition underway: “we’re now going from a science phase into a real engineering phase, and that’s where we need the EPC to help us.”
Speakers also noted the importance of thinking beyond the fusion engine itself, and ensuring that full facilities are designed with long-term operation in mind.
Despite these challenges, all speakers agreed on one point: EPC involvement will eventually be needed for fusion to scale. Building cooperation early and addressing delivery issues upfront will help make whole-plant integration more cost effective and support the ambitious timelines of many developers.
For EPCs looking to stay ahead of these developments, keeping up to date with how fusion projects, delivery models and timelines are evolving is essential. Our FEI Premium subscription supports this through our in-depth Quarterly publication, alongside ongoing industry analysis and expert discussion.
FEI Premium subscribers of Fusion Energy Insights can watch the full replay of the Q&A which offers a deeper insight on EPCs via our Circle platform.