HSG start-up fortyfour filters CO₂ from the air

The climate-tech start-up fortyfour, founded by HSG graduate Henry Müller, has commissioned its first direct-air-capture plant at the Swiss vegetable producer Meier Gemüse, near Brugg (AG). Since September 2026, the plant has been producing CO₂ on-site directly from the air and feeding it into the greenhouse, where it promotes vegetable growth. It is fortyfour’s first plant to be operational at a commercial producer’s site.

On-site CO₂ instead of CO₂ from natural gas

The plant thus replaces CO₂, which is usually produced from natural gas and delivered by lorry. “Growers need CO₂ every single day, but have little say in where it comes from. We want to change that – with a plant that produces it right next to the greenhouse, directly from nature. We are very grateful to Meier Gemüse for placing their trust in our first plant,” says Dr Henry Müller, CEO and co-founder of fortyfour.

Fortyfour took part in the HSG’s start-up support programme

Müller completed his PhD at HSG. With fortyfour, he was one of the first participants in the Entrepreneurial Champions Programme (ECP) run by HSG Entrepreneurship. This programme supports technology-driven start-ups founded by HSG members for one year with a total of 100,000 Swiss francs, as well as coaching, consultancy and access to a network. “I’m grateful that this allowed me to devote myself entirely to the start-up,” says Müller.

“As a research-intensive start-up, fortyfour relies on funding because there is still a long way to go before commercialisation. During the ECP, I was able to raise many times more funding than I would have otherwise, which would have required a much greater effort without the support.”

Müller also benefited in other ways, as he explains: “Although the technology needs to be developed, in its early years a start-up thrives primarily on its vision, fundraising and close customer engagement for market validation. That is exactly what you learn at HSG, and that is exactly what got us to the point of securing our first investment from the vegetable producer.”

Patent application filed for fortyfour’s technology

Müller founded the St. Gallen-based start-up in 2025 together with Pedro Reina, a graduate of the Lucerne University of Applied Sciences and Arts. Since then, the pair have been working intensively on developing the technology and the company. The young company is also supported by the Swiss Federal Office of Energy.

fortyfour’s systems extract CO₂ from the air surrounding the greenhouse. Inside, a special liquid solvent binds the CO₂ from the air. When the solvent is gently heated, it releases the CO₂, which then flows into the greenhouse’s existing CO₂ pipes. As this process works at low temperatures, the system can be powered entirely by electricity – or, alternatively, by waste heat already available on site. Because it uses a liquid, the system is very compact and requires only a few square metres compared with other, previously tested direct air capture approaches. A patent application has been filed for the process.

“For most producers, CO₂ is a supplied commodity over which they have little control,” explains Müller. The majority of this CO₂ is produced as a by-product in fertiliser plants powered by natural gas: there, it is captured, liquefied and transported by lorry to the producer. If these plants scale back their production or shut down, supplies can be disrupted at short notice – replacements are hard to find and expensive. Added to this is the fact that prices for fossil-based CO₂ are rising steadily due to higher taxation, whilst major retailers are also pushing for decarbonisation.

Following this initial deployment, fortyfour is seeking further pilot partners amongst greenhouse and indoor farm operators to test the technology under various climatic conditions, crops and circumstances.