Making fuel out of air isn’t science fiction; it’s the operating thesis behind Prometheus Fuels’ “reverse combustion” platform — and the focus of a recent Munro Live conversation with founder and CEO Rob McGinnis.
For Munro’s audience of engineers, EV enthusiasts, and investors, the appeal is immediate. Prometheus delivers a compact, scalable system designed to produce carbon-neutral, drop-in fuels at a lower cost than fossil options. The approach turns combustion on its head.
Rather than burning fuel and releasing CO₂, Prometheus flips the process. It pulls carbon dioxide straight from the air, combines it with water, and uses low-cost solar electricity to form new hydrocarbons. As a result, the system creates usable liquid fuel and returns clean oxygen to the atmosphere. This closed loop operates efficiently, emphasizing speed, simplicity, and scalability — a fitting case study for Munro’s teardown-driven approach to innovation.
Reverse Combustion, Explained
Think of Prometheus’ process as combustion in reverse. Instead of burning gasoline to create CO₂ and water, the system ingests CO₂ and water, then uses electricity to produce hydrocarbons. The company’s first-of-a-kind hydrocarbon electrolyzer — packaged as modular “Faraday” reactor stacks — is the heart of the plant. These stacks operate at room temperature and atmospheric pressure, relying on plastic parts, PVC plumbing, and standard pumps rather than high-temperature, high-pressure equipment. The simplicity matters for cost, reliability, and speed to scale.
A complementary membrane unit, known as the “Maxwell core,” takes efficiency a step further. It separates alcohols far more effectively than conventional distillation, cutting both weight and energy demand. As a result, Prometheus can build lightweight, electrically driven “all-electrons” plants. These systems produce methanol, ethanol, isopropanol, and other fuels without the need for high-temperature thermal processes. In essence, the Maxwell core replaces heat with precision — and speed — powered entirely by electricity.
From Forge to Foundry — Designed to Scale
Prometheus frames two build modes: a 40-foot containerized “Titan fuel forge” for distributed production and larger warehouse-style “foundries” that pack many Faraday stacks. Output scales by adding stacks — much like adding battery modules to increase EV range. A typical container integrates direct-air-capture hardware (cooling-tower-like contactors with a roof fan) and the electrolyzer loop; McGinnis quotes roughly 200 tons CO₂ capture per year per 40-foot unit. For mass adoption, stacks are designed for injection-molded plastic plates and automated assembly, driving down capex as volume ramps.
The manufacturing vision goes further, extending to a “metaforge” — a factory designed to build other forges and foundries through automotive-style mass production. In this model, standardized parts and automated assembly drive scale and consistency.
For readers familiar with Munro’s lean design ethos, the parallels stand out. The same principles apply here: reduce part count, rely on commodity materials, and design for repeatable, logistics-friendly builds. In short, Prometheus is applying lean manufacturing discipline to fuel production itself.
Why Cost — Not Just Carbon — Is the Wedge
Prometheus targets price parity or better versus fossil fuels by exploiting ultra-cheap off-grid solar. McGinnis points to sub-$0.01/kWh solar in high-insolation regions using private, off-grid arrays. At those electricity prices, equipment cost dominates the levelized fuel cost; the company can even “dial” the stack for lowest-cost operation at ~44–45% electricity-to-fuel efficiency, or up to ~60% if optimizing strictly for energy efficiency. The only byproduct is oxygen; the plant’s air filters also remove particulates, providing a local air-quality co-benefit.
For mobility, energy density still rules. Hydrocarbon fuels sit in the upper-right of a Ragone-style landscape; batteries cannot yet match jet-A for long-haul aviation. Prometheus’ synthesis yields the same families of molecules — C4–C12 for gasoline, C8–C16 for jet, C8–C20 for diesel — which can be blended with standard additives and seasonal specs to “drop in” to existing engines and distribution.
Product Roadmap and Customers
The near-term product is methanol — already usable for marine applications, racing, and as a precursor to gasoline, diesel, and jet fuel via downstream conversion. Prometheus’ first commercial project, “Project Lodestone,” is planned at 100,000 tons/year of methanol made from off-grid solar; McGinnis says it is sold out for 10 years with a waitlist. A follow-on “Loadstar” project aims for ~1 million tons/year, likewise pre-sold. While partner names remain unannounced until site groundbreaking, the pipeline spans aviation, maritime, and industrial plastics via syngas integrations.
At the time of the discussion, Prometheus had one commercial pilot running at its headquarters, while site selection for the first full-scale project was already underway. Meanwhile, independent engineering firm Ramboll had evaluated the technology twice. Earlier reviews placed it around TRL 6–7, confirming it had moved beyond lab-scale testing.
Now, the company reports that production-ready stacks and site architecture are fully defined. As a result, Prometheus eliminates the costly prototype-to-plant transition that often delays or derails scale-ups.
Engineering Takeaways for Lean, Low-Capex Fuel
- Design for injection molding: The Faraday stack plates are plastic; once tools are cut, per-unit costs converge toward raw material cost plus ~5% at scale. For teardown minds, it’s the same playbook that made consumer hardware cheap and consistent — but applied to electrochemical reactors.
- Integrate unit ops around electricity: The Maxwell core membrane eliminates thermal distillation loads; pumps, pipes, and filters stay at ambient conditions, simplifying safety, maintenance, and permitting.
- Modular power-in, fuel-out: Containerized forges and rackable stacks turn projects into “count the modules” exercises. This spreads execution risk and accelerates ramp compared with bespoke refinery trains.
- Exploit siting arbitrage: Off-grid solar unlocks ultra-low LCOE; when electricity is that cheap, the lever becomes manufacturing scale and yield — not heroic efficiency gains.
What It Could Mean for EVs and the Broader Fleet
EVs win on efficiency, maintenance, and urban emissions, and Munro’s teardowns show the cost curve bending as power electronics and packs integrate. Still, aircraft, blue-water shipping, legacy ICE fleets, and remote operations need high-energy-density liquids.
Creating fuel from captured air complements electrification by decarbonizing those hard-to-electrify legs without ripping and replacing engines, tanks, and global logistics. For investors, the thesis is durable: a platform that sells molecules into multiple verticals — mobility fuels, industrial syngas, even beverage-grade ethanol — while benefiting from the same capex learning curves seen in PV and batteries.
Risks and Reality Checks
Execution risk remains: injection-mold tooling, automated stack assembly, balance-of-plant reliability, membrane lifetime, and fouling rates must validate at fleet scale. Seasonal gasoline specs and additive packages require robust QA. And while methanol is a pragmatic entry, on-spec jet and diesel blends must demonstrate consistent performance and infrastructure compatibility across climates.
That said, the architecture’s ambient-condition simplicity, oxygen-only byproduct, and module-based scaling reduce several classic chemical-plant risks. The market pull appears real, with multi-year offtakes cited across aviation, maritime, and plastics.
Where Creating Fuel Out of Air Fits Next
For automotive and aerospace engineering leaders, the practical question is siting and integration: where does a forge or foundry slot beside solar to feed your fleet or plant with contract-priced liquids? Meanwhile, for municipalities, consider distributed air capture and fuel synthesis as an air-quality co-benefit around ports. For investors, diligence membranes, stack longevity, and manufacturing yield; if those vectors hold, the TAM is refinery-scale.
Keep Learning with Munro
Want deeper teardown-level insight into Prometheus’ Faraday stacks, membranes, and system integration — and where turning air into fuel could complement electrification? Explore more interviews, cost breakdowns, and expert analysis at Munro & Associates or subscribe to Munro Live today.