Rob McGinnis on Turning CO₂ Into Fuel, Electrofuels, and the Future of Energy
In this episode of the Founders in Arms podcast, we sit down with Rob McGinnis, co-founder and CEO of Prometheus Fuels, a company developing technology that converts carbon dioxide from the air into liquid fuels using renewable electricity.
Prometheus Fuels aims to create carbon-neutral gasoline, diesel, and jet fuel without changing existing engines or infrastructure. Instead of electrifying everything, Rob argues we can recycle carbon from the atmosphere and turn renewable power into liquid fuels that work with the world’s existing energy systems.
The conversation dives deep into the science behind electrofuels, the economics of renewable energy, and why the future of energy may combine solar power, electrochemistry, and atmospheric carbon capture.
This conversation dives deep into:
Turning CO₂ into gasoline, diesel, and jet fuel
Electrofuels and renewable energy storage
Direct air capture technology
Carbon nanotube membranes and advanced materials
Why batteries won’t solve every energy problem
Hydrogen vs liquid fuels
Energy infrastructure and decarbonization
Building deep-tech startups
In this episode, we cover:
(00:00) Turning CO₂ from the air into fuel
Rob explains the core idea behind Prometheus Fuels.
The company captures carbon dioxide directly from the air and combines it with renewable electricity to produce fuels like:
methane
gasoline
diesel
jet fuel
These fuels act like energy storage, allowing electricity from solar or wind to be stored in chemical form and used later.
(04:32) Rob’s path from academia to startups
Rob’s journey started during his PhD in environmental and chemical engineering.
His first company focused on desalination technology and advanced membranes for industrial wastewater treatment. After realizing he preferred startups to academia, he started building new materials using carbon nanotube membranes.
That technology eventually led to the idea for Prometheus Fuels.
(07:34) Why cheap renewable electricity made electrofuels possible
Prometheus was founded in 2018, when solar electricity prices dropped below 2 cents per kilowatt-hour.
At that price, converting electricity into fuels becomes economically viable.
If renewable electricity continues to fall in cost, synthetic fuels could become cheaper than fossil fuels.
(09:30) How Prometheus turns CO₂ into hydrocarbons
The process involves three core steps:
Capture CO₂ from the air using water-based chemistry.
Use electrochemistry to convert the carbon into hydrocarbons.
Separate fuels from water using specialized membranes.
The system runs at room temperature and atmospheric pressure, making it much cheaper than traditional fuel synthesis methods.
(11:18) The electrochemical reactor
The core system is a modified hydrogen electrolyzer.
Inside the reactor:
electricity splits water into hydrogen and oxygen
the hydrogen bonds with carbon from captured CO₂
hydrocarbon chains form directly in the reactor
This allows Prometheus to produce fuels ranging from methane to jet-fuel-range hydrocarbons.
(14:22) Carbon nanotube membranes
A key breakthrough in Prometheus’s process is a membrane built using carbon nanotubes.
These membranes separate fuel molecules from water without expensive distillation.
Instead of boiling large volumes of water, the membrane selectively absorbs fuel molecules and extracts them efficiently.
(20:15) Economics of synthetic fuels
Rob claims Prometheus could eventually produce fuels for less than $3 per gallon without subsidies.
The cost advantage comes from:
ultra-cheap renewable electricity
simple electrochemical reactors
avoiding expensive distillation
If successful, synthetic fuels could compete directly with fossil fuels.
(24:30) Scaling fuel production
Prometheus plans to deploy production units inside shipping-container-sized modules called fuel forges.
Each unit can produce around 50,000 gallons of fuel per year.
Large projects could combine hundreds of units to produce millions of gallons annually.
(30:00) Why e-fuels solve renewable energy bottlenecks
One advantage of electrofuels is that they can be produced far from cities.
Solar farms in remote locations often generate electricity that cannot reach the grid due to transmission constraints.
Prometheus could convert that stranded power into fuel and transport it globally.
(36:30) Why deep-tech startups move slowly
Despite raising around $50 million, Prometheus remains a small team of about 20 people.
Building hardware companies requires solving many small engineering challenges:
manufacturing tolerances
materials compatibility
automation systems
chemical stability
These details often slow down commercialization.
(41:55) Why the company raised relatively little funding
Prometheus reached a $1.5B valuation after its Series B.
But Rob deliberately avoided raising large rounds to preserve focus and avoid narrative battles around climate technology.
Instead, the company plans to prove its technology through commercial production first.
(47:00) Why deep-tech breakthroughs often face skepticism
Rob describes resistance from parts of the scientific and venture communities.
When new technologies challenge established assumptions, researchers and investors may initially dismiss them.
He believes that successful demonstrations will ultimately settle the debate.
(53:30) CO₂ removal vs fuel production
Some climate startups focus on carbon removal, capturing CO₂ and storing it underground.
Prometheus instead focuses on recycling carbon into fuels.
Rob argues that replacing fossil fuels with carbon-neutral fuels is a faster way to reduce emissions.
(1:05:00) What the energy system might look like in 10 years
Rob predicts a mixed energy future:
batteries for many vehicles
synthetic fuels for aviation and shipping
renewable electricity powering fuel production
Instead of replacing all infrastructure, electrofuels could decarbonize existing engines and energy systems.
Key Takeaways for Founders
Cheap renewable electricity unlocks new industries
As solar and wind costs fall, entirely new energy systems become economically viable.
Deep-tech startups require patience
Progress often depends on solving small engineering challenges rather than making big conceptual breakthroughs.
Infrastructure matters
Technologies that integrate with existing infrastructure can scale much faster than those requiring global replacements.
Narratives shape funding
When startups challenge dominant industry assumptions, they often face skepticism even with strong data.
Energy abundance could reshape the world
If renewable electricity becomes extremely cheap, it could transform transportation, manufacturing, and global energy markets.
About the Guest
About Rob McGinnis
Rob McGinnis is the co-founder and CEO of Prometheus Fuels, a company developing technology that converts atmospheric CO₂ into carbon-neutral fuels using renewable electricity.
He previously founded companies in water technology and advanced membranes after completing a PhD in environmental and chemical engineering at Yale. His work focuses on energy systems, carbon capture, and advanced materials.
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