The sustainable aviation fuel industry has a power problem. Producing eSAF (electro-sustainable aviation fuel, also called Power-to-Liquid or PtL SAF) requires enormous volumes of green hydrogen, which requires enormous volumes of clean electricity. The pathway is well understood: use electrolysis to split water into hydrogen and oxygen, capture CO2 from the atmosphere or industrial sources, then combine them via Fischer-Tropsch synthesis into drop-in jet fuel. The chemistry works. The economics don’t, yet, because the electricity bill is ruinous.

This is where nuclear energy re-enters the conversation. Not the gigawatt-scale plants of the 1970s, but a new generation of small modular reactors (SMRs) designed to be factory-built, deployed in clusters, and operational by the early 2030s. In the past two weeks alone, Rolls-Royce SMR signed an MoU with UK project developer Equilibrion to assess nuclear-powered SAF production, and Bristol Airport published a feasibility study concluding that SMRs could supply both SAF and hydrogen for the South West region. These aren’t theoretical exercises. They’re responses to a specific, calculable gap in the eSAF supply chain.

Why eSAF Needs 24/7 Power (and Why Renewables Alone Can’t Deliver It)

The core challenge is capacity factor: the percentage of time a power source actually generates electricity. Nuclear plants operate at roughly 80% capacity factor, meaning they produce power around the clock, nearly year-round. Offshore wind runs at about 43%. Onshore wind at 34%. Solar PV at just 18%.

For eSAF production, this matters enormously. Electrolysers are capital-intensive equipment. When they sit idle because the wind isn’t blowing or the sun isn’t shining, the cost of the hydrogen they produce rises proportionally. An electrolyser running at 80% utilisation produces hydrogen at roughly half the cost per kilogram of one running at 40%. Nuclear power effectively guarantees that utilisation rate.

The numbers tell the story. To meet equivalent hydrogen demand, nuclear power would require 957 GW of installed capacity. The same demand would require 1,775 GW of offshore wind, 2,243 GW of onshore wind, or 4,240 GW of solar PV, according to World Nuclear Association analysis. That’s not an argument against renewables for grid electricity. It is an argument that for industrial-scale hydrogen production feeding an eSAF plant, a baseload power source changes the economics fundamentally.

Nuclear power effectively guarantees the 80% electrolyser utilisation rate that makes green hydrogen economics viable for eSAF production.

What SMRs Bring That Traditional Nuclear Doesn’t

The appeal of SMRs over conventional nuclear plants comes down to three factors: cost, speed, and flexibility.

Traditional nuclear plants cost $10-15 billion and take 10-15 years to build. SMRs are designed to cost $2-5 billion per unit and reach operation within 5-7 years from construction start. Rolls-Royce SMR’s design, currently progressing through UK regulatory approval, targets 470 MW of electrical output per unit with the ability to deploy in clusters. Because the reactors are factory-manufactured rather than site-built, construction timelines are more predictable and costs decline with each unit produced.

For eSAF specifically, SMRs offer a dual output advantage: they produce both electricity (to power electrolysers) and process heat (useful for the Fischer-Tropsch synthesis stage). Conventional renewable sources provide electricity only. This dual capability means an SMR-powered eSAF facility could be more thermally efficient than a renewables-powered equivalent, extracting more useful energy per unit of installed capacity.

The UK Is Moving First

The UK government’s SAF mandate, enacted through the Revenue Certainty Mechanism, requires 0.5% PtL SAF by 2030, rising to 3.5% by 2040. These are small percentages, but the absolute volumes are significant: the UK consumed approximately 12.3 billion litres of jet fuel in 2023. Meeting the 2040 PtL target alone would require over 430 million litres of eSAF annually.

Equilibrion, the UK-based project developer driving much of the current activity, has developed a proprietary system called Eq.flight that integrates SMR power output with electrolysis and fuel synthesis in a single facility design. Their analysis, conducted alongside the Rolls-Royce SMR MoU, estimates that a single Rolls-Royce SMR could produce over 160 million litres of eSAF per year. That would meet roughly a third of the UK’s 2040 PtL target from one reactor.

The Bristol Airport feasibility study, funded through the airport’s Airport Carbon Transition (ACT) programme and conducted with support from Q8Aviation and pipeline operator Exolum, concluded that SMRs sited in the South West could generate the electricity and process heat to supply both SAF and hydrogen for regional aviation. Equilibrion estimates the approach could reduce emissions from flights operating at Bristol Airport by approximately 29% by 2035.

Who Else Is in the Nuclear-eSAF Space

Beyond the UK, the nuclear-eSAF intersection is attracting attention from multiple directions. In North America, a proposed strategic collaboration between XCF Global, Southern Energy Renewables, DevvStream Corp., and IP3 Corporation would combine SMR development with eSAF production and carbon credit monetisation. While still at the MoU stage, the structure signals how nuclear-powered fuel production could be financed: bundling the fuel output with tradeable environmental attributes to improve project returns.

Meanwhile, the broader nuclear renaissance, driven primarily by AI data centre demand for 24/7 clean power, is creating an infrastructure tailwind that eSAF producers can ride. Microsoft, Google, and Amazon have all signed nuclear power agreements in the past 18 months. Every SMR that gets built for data centre power makes the next one cheaper and faster to deploy, reducing costs for all applications, including fuel production.

The Reality Check

None of this is operational yet. Rolls-Royce SMR’s first reactor is targeting the early 2030s. Equilibrion’s Eq.flight system is at the assessment stage. No nuclear-powered eSAF plant has broken ground anywhere in the world.

The timeline risk is real. Nuclear projects have a long history of cost overruns and delays. If SMR deployment slips by 3-5 years (which nuclear sceptics consider likely), the window for meeting 2030 PtL mandates closes entirely, and even 2035 targets become strained.

There’s also the social licence challenge. Nuclear power remains politically contentious in many jurisdictions. Siting an SMR near an airport or fuel distribution hub, which is where it would need to be to minimise hydrogen transport costs, will require public engagement that hasn’t begun in most regions.

And renewables aren’t standing still. Green hydrogen costs from wind and solar have fallen roughly 40% since 2020. If that trajectory continues, the capacity factor disadvantage may be partially offset by lower per-MWh generation costs, particularly in high-solar regions like the Middle East, North Africa, and the American Southwest.

Key Takeaways

• eSAF production requires massive volumes of continuous clean electricity. Nuclear SMRs operate at ~80% capacity factor versus ~18% for solar and ~34-43% for wind, potentially halving electrolyser-produced hydrogen costs.
• A single Rolls-Royce SMR could produce over 160 million litres of eSAF annually, meeting roughly a third of the UK’s 2040 PtL mandate from one reactor, according to Equilibrion’s analysis.
• The Bristol Airport feasibility study (funded through the ACT programme, with Q8Aviation and Exolum) concluded SMRs could reduce regional aviation emissions by approximately 29% by 2035.
• No nuclear-powered eSAF plant is operational or under construction anywhere in the world. The earliest realistic timeline is early 2030s, dependent on SMR regulatory approval and construction timelines holding.
• The AI-driven nuclear renaissance (Microsoft, Google, Amazon power deals) is creating an infrastructure tailwind that reduces SMR deployment costs for all applications, including eSAF.

Source: Rolls-Royce SMR | Equilibrion | World Nuclear Association