The Orcas slide elegantly through the seas, always looking for prey. No sooner have they found their victim than they have struck them power­fully. But what do killer whales, also called orcas, have to do with improving air? In Island, “orca” stands for power, strength and energy. All of this also applies to the latest CO₂ suction unit from the Swiss company Clime­works in Iceland. With 4,000 tons of filtered carbon dioxide per year, “Orca” is currently the most powerful system for direct air capture (DAC) world­wide.

In addi­tion, the system is supplied directly with heat energy from the ground by the geot­hermal power plant from Hell­isheiði. “We have a climate-friendly energy source on site,” explains Nathalie Casas, Head of R&D at Clime­works. “This enables us to supply the fans with clean power and use the geot­hermal heat directly to release the CO₂ from the filter mate­rial.”

Adapted to rugged nature

Thanks to geot­hermal energy, Iceland is an ideal loca­tion for the Orca, were it not for the change­able weather and the sulfurous air on the volcanic island. This is why Clime­works relies on partic­u­larly weather-resis­tant compo­nents, robust axial fans from ebm-papst and Amin filter mate­rial in its system. “This mate­rial binds CO₂ very well, espe­cially in cold and humid weather,” explains Casas. In addi­tion, the company has not only adapted its system to the diffi­cult envi­ron­mental condi­tions from a tech­nology perspec­tive. Orca also fits into Iceland’s rugged land­scape with its earth-colored facade.

With its facade, the “Orca” DAC system fits into the Icelandic land­scape. ©2022, Clime­works

In addi­tion to its wood optics, the CO₂ intake also impresses with its perfor­mance. After all, twelve axial fans each work in eight containers in the Orca. Clime­works reduced the amount of steel installed in the container and increased the filter surface. As a result, Orca can absorb more carbon dioxide in the same time as its prede­cessor “Capri­corn” in Hinwil, Switzer­land – around 500 tons per container per year. In addi­tion, a container is no longer made up of many indi­vidual filter modules with unused spaces but is now a module in itself.

From the air to the ground

More fans and more filter mate­rial make Orca the most effi­cient CO₂ suction unit in the world. ©2022, Clime­works

But what actu­ally happens with the filtered carbon dioxide? It is pressed back into the floor and stored there. To do this, Clime­works uses the geot­hermal circuit of Hellisheiði’s power plant, which conveys hot deep water from the ground to generate elec­tricity and heat and then feeds the water back into the ground. In the final step, Clime­works feeds the CO₂ filtered by Orca into the water. As a result, it gets around 800 to 2,000 meters deep into the ground, where it crys­tal­lizes under the high pres­sure and is deposited.

There­fore, Orca completely devours CO₂. But when it comes to Clime­works, the system is just another step among many in the fight against climate change, because filtering just one percent of global CO₂ emis­sions per year would require 87,000 more DAC systems like Orca. That is why, the whale will soon not be the only one hunting CO₂. Clime­works is already plan­ning the next systems. One of them is set to go into oper­a­tion at the end of 2023, also in Iceland, and will be ten times as large as Orca. Further systems are set to follow by 2028, which may even be a hundred times larger.