Direct Action: GE Research Gets Into Direct Air Capture to Tackle Legacy CO2

Fighting today's emissions is one kind of project, but what about fighting yesterday's? The world has been pumping out carbon dioxide since the industrial revolution, building a mountain of CO₂ that won't be dislodged by new solar power or electric vehicles. An emerging approach to attack this legacy CO₂ is direct air capture, or DAC. Vacuuming up existing CO₂ molecules, DAC is like a giant air-freshening machine that collects carbon dioxide and then compresses it for burial underground or utilization in sustainable aviation fuels, concrete, petrochemical products, and plastics, among others. GE, with its historical expertise in airflow technology, thermal management, and materials science, has now jumped into the DAC game. GE Research is testing its own sorbent-based DAC system and is preparing to scale the technology to a much bigger level. "The initial results are impressive, and just a tremendous milestone in the project," says David Moore, the carbon capture breakout technology leader for GE Research. According to Moore, his group will be supersizing its model system more than 20-fold for a new round of tests starting next year.

GE's pursuit of its own direct air capture solution is an outgrowth of its previous work with the Defense Advanced Research Projects Agency, or DARPA, and its effort to capture not carbon but water from arid desert air. "The DARPA AIR2WATER project really was the starting point for a lot of this technology. We proposed the fundamentals of the system that we've now translated, or evolved, for direct air capture," says Moore. GE also works with the energy wing of the Advanced Research Projects Agency-Energy (ARPA-E) and the Department of Energy's Office of Fossil Energy and Carbon Management (DOE-FECM) to accelerate breakthroughs in a range of CO₂ removal technologies. GE's focus in carbon management spans both direct air capture as well as developing carbon capture solutions for gas-fired combined-cycle power plants worldwide - both of which are critical to longer-term climate action.

Direct air capture is currently operating at just 18 plants worldwide, according to the International Energy Agency (IEA). But all of these are at a very small scale, able to capture just 0.01 million metric tons of CO₂ per year collectively. To stay on track to meet the IEA's 2050 net zero goals, DAC will need to scale up from this tiny level to capture 60 million metric tons per year by 2030. The big challenge right now is cost. According to Moore, DAC technology employed today would capture carbon at a cost of $500 to $1,000 per metric ton. Other estimates range from $250 to $600 a metric ton, as cited by the World Resources Institute. But the true cost is not really known, for the simple reason that DAC is new, has not yet scaled up past 0.004 million metric tons per year, and has not yet benefited from the cost declines that will arrive when the technology begins to multiply.

The innovation engine driving GE's advance into DAC technology is the Climate Action @ GE (CAGE) Lab, GE Research's preeminent research-and-development laboratory for advancing carbon capture and many adjacent technologies aimed at climate action. There, with the help of machine learning, scientists are able to combine and recombine a veritable kaleidoscope of sorbent materials to produce the chemistry that will capture CO₂ best. Moore says this is like iterating a cake mix, over and over. For its DAC model, GE has taken the most efficient version from these experiments and made it into a coating that covers the large surface area of a heat exchanger. When air passes over this coating, called a sorbent composite, it acts like a sponge. First CO₂ is "adsorbed," and then in other parts of the DAC equipment it is "desorbed" to yield CO₂ in storable or usable form.

GE has a long history of starting out at the small experimental level and building solutions upward to world-scale manufacturing capability. Moore says his colleagues at GE Vernova, GE's portfolio of energy businesses, call this creative process "going from powder to plant." You're essentially starting "with something at the angstrom level, a molecule, and eventually going up to a plant that will cover many acres," he says. GE Research has a deep bench of people, at least 50 according to Moore, involved in every area of the DAC pursuit, as well as post-combustion capture and atmospheric water extraction. And that doesn't include all the external partnerships with academic and industrial partners, as well as the Department of Energy. "I really want to emphasize the collaborative effort," says Moore. "It takes a village …"

As GE embarks on the scale-up to a much bigger DAC model next year, it will join the race, along with the rest of the world, to knock down the cost of CO₂ capture to the holy grail of $100 per metric ton of CO₂. That cost figure is the one identified by the Department of Energy's 2021 "Carbon Negative Earthshot" as part of the ambitious goal to remove CO₂ "at the gigaton scale." For comparison, the DOE explains that each gigaton of CO₂ removed from the atmosphere is equivalent to the annual emissions of 250 million vehicles in the U.S.

The $100 level is not a coincidence. That's roughly the price global industry already pays for purchased CO₂ used in industrial applications. So a future fleet of DAC installations - which will look like very large power plants, with high walls and large banks of whirling fans - would become economically viable when they can produce a metric ton of CO₂ for closer to the market price. In such a scenario, not only would the world continue to curb new emissions, but it could finally begin to chip away at the old emissions.

Top image: Five of the 50-plus scientists and engineers who make up GE's Carbon Capture Breakout Team, shown at GE's CAGE (Climate Action @ GE) Lab, on the GE Research campus in Niskayuna, New York, where the successful testing of its first direct air capture (DAC) prototype unit occurred. The lab has become a major research hub for the company's larger commitment to decarbonization technologies. Credit: GE Research.