Aerleum Plans to Turn CO2 Directly Into Fuel for Cargo Ships and, Eventually, Airplanes

It only took four phone calls for Sébastien Fiedorow to quit his job as a venture capitalist.

The first one came from Marble, a startup studio based in Paris. They had a scientist looking for help founding a company that would remove carbon dioxide directly from the atmosphere — what experts call direct air capture, or DAC.

“They approached the subject as being a DAC company, and I was like, ‘No, no way. I won’t go in that space,” Fiedorow told TechCrunch. “I didn’t want to invest in DAC.”

But he kept an open mind and met with the scientist, Steven Bardey. After a few meetings with his co-founder, he was “all in,” he said. “Once we dug into the numbers, once we did a back-of-the-napkin techno-economic assessment, that was the switching point for me.”

Fiedorow and Bardey started Aerleum in 2023 to refine the DAC technology that Bardey had been working on. Most DAC companies focus on the capture part of the process, designing what are essentially large sponges that can soak up carbon dioxide from the atmosphere. It’s not easy or cheap: even at today’s elevated levels, CO2 represents just 0.04% of the air we breathe.

Once captured, many DAC startups then have to find a buyer for that carbon dioxide. They can compress it and sell it to oil companies, which force it into reservoirs to squeeze out more oil, thereby blunting it as a solution for climate change. Or they might sell it to a sequestration startup, which simply injects it deep into the Earth for storage. Still, other companies might sell it to chemical companies, which transport it to their facilities and turn it into other compounds.

“Should we really have to get through all of these steps, or can we just bypass some of them?” Fiedorow said, describing his and Bardey’s thought process. “Where do you have the most energy penalties? It was really in the middle, the intermediate steps where you have to dissolve the CO2, compress it, and transport it.”

To cut out that step, Aerleum has developed a material that, in a two-step process, absorbs carbon dioxide and transforms it into another compound.

The startup’s first target is methanol, an alcohol that can be burned as fuel in cargo ships or used as an ingredient to make other chemicals, including aviation fuel. The proprietary material is sponge-like, Fiedorow said, and inside the pores, a catalyst helps facilitate the chemical reactions that Aerleum is pursuing.

To capture carbon dioxide, Aerleum places the material into a sort of box that air can flow through. Once the material is saturated with carbon dioxide, the technology closes the box and starts pumping in hydrogen gas. The hydrogen then reacts with the carbon dioxide to produce gaseous methanol. The methanol is pumped out of the box and purified.

For now, Aerleum is focused on using the CO2 that’s already in the atmosphere, but Fiedorow said the company has run tests using up to 15% carbon dioxide, so it’s possible the material could be used to capture the gas from some industrial processes.

To build a pilot of its DAC device, Aerleum has raised $6 million in seed funding from 360 Capital and HTGF with participation from Bpifrance, Marble, and Norrsken.

In the near term, the company hopes to be able to produce methanol using its process for under $1,200 per metric ton. Right now, the cost of methanol ranges from around $380 to $780 per metric ton to buyers, depending on where they’re located.

In five years, Fiedorow said, the goal is to cut that nearly in half, to $650 per metric ton. “That’s where we start to be super competitive, even with fossil fuels,” he said.