A model pairs air-captured water and CO₂ for green methanol

At Forschungszentrum Jülich, a possible source of process water is floating overhead. A modeled methanol plant would pull carbon dioxide and water from the air together, giving sun- and wind-rich regions a route to renewable fuel without drawing on local freshwater. The work, led by Henrik Wenzel of Jülich Systems Analysis, was published in Nature Communications.

The mechanism is direct air capture (DAC): a filter binds CO₂ while also absorbing moisture. Instead of treating that water as an unwanted side effect, the concept feeds it into methanol production. Jülich’s model includes renewable electricity, electrolysis, energy storage, heat utilization and cooling, with no additional water consumption.

The researchers tested the idea across more than 20,000 regions in 78 countries expected to face at least medium water stress in 2050. In around 97% of them, the air contains enough water over the course of a year to supply the process. Even in very dry locations, the model says production could in principle work if the plant ran mainly during more humid hours and stored water temporarily.

The practical payoff is a wider choice of sites for green methanol, which is used in plastics, paints and other chemical products and is gaining importance as a marine fuel. Jülich projects production costs in 2050 at several hundred euros per tonne in favorable locations, while less suitable sites could cost several times more. The current European contract price is just under €1,000 per tonne, although market prices fluctuate and the study models future costs.

So what changes, concretely? A region with strong wind and solar resources would not automatically be ruled out because it lacks abundant freshwater. But this is still a techno-economic model, not an operating factory: local financing, labor, infrastructure and material shortages are not fully captured, and flexible high-temperature electrolysis has yet to prove itself in continuous industrial use.

There is also a local question beyond the plant boundary. The DryHy project is examining whether removing water vapor at large scale could affect humidity, clouds or precipitation. Thomas Schöb of Jülich says that avoiding freshwater withdrawals does not by itself establish that atmospheric water removal has no consequences, so each proposed site would need its own assessment before very large plants are built.