Swiss climate tech company Climeworks announced yesterday that it has broken ground on its biggest facility yet for capturing carbon dioxide from the air. The new Direct Air Capture (DAC) plant, named Mammoth, will significantly scale up the company’s operations in Hellisheiði, Iceland.

That’s where Climeworks built Orca, which was the largest DAC plant in the world when it came online last September. Orca can capture up to 4,000 tons of carbon dioxide a year, roughly equivalent to how much climate pollution 790 gas-guzzling passenger vehicles release annually. Mammoth, in comparison, can capture about nine times as much CO2 as Orca.

There are fewer than 20 such plants in the world, according to the International Energy Agency (IEA), and they don’t yet have the capacity to make a serious dent in the greenhouse gas emissions humans have dumped into the atmosphere. The IEA says that to do that, the direct air capture industry has to grow to be able to draw down 85 million metric tons of CO2 by the end of the decade. For comparison, it captures just 0.01 million metric tons today. (The Verge visualized the scale of the task earlier this year, which you can check out here.)

That’ll likely require a new generation of DAC plants, each capable of taking in 1 million metric tons of CO2 per year. So in the grand scheme of things, Mammoth — with the capacity to capture 36,000 tons of CO2 a year — isn’t quite so mammoth. Even so, Mammoth is an important test case for scaling up Direct Air Capture tech.

One of the usual drawbacks to Direct Air Capture as a climate fix is how much energy it takes to power this kind of facility. Luckily, both Mammoth and Orca are located within the ON Power Geothermal Park at Hellisheiði, so they can use nearby renewable geothermal energy and waste heat to separate CO2 from air. (You can read The Verge’s story about how Climeworks’ tech works here.)

There’s a larger plant under construction in Texas that’s supposed to be able to capture up to 1 million tons of CO2 by the time it’s operational in 2025. But that uses a different kind of filtration process that requires much hotter temperatures to take CO2 out of the ambient air. As a result, that operation is likely to rely on a combination of renewable energy and natural gas and will have to capture emissions from its own gas consumption. That project is backed by petroleum company Occidental, and some of the carbon it captures is expected to be used in a process that retrieves harder-to-reach oil reserves by injecting CO2 into the ground.

That’s not the case so far with Mammoth and Orca, where the plan is to turn the CO2 into stone. Their location is also ideal because the carbon it captures can be stored underground nearby. Climeworks is working with another company called Carbfix to lock the CO2 away in the region’s basalt rock formations that, thanks to Iceland’s volcanic activity, have more nooks and crannies to fill than older basalt rock. That storage space minimizes the need to build out new networks of pipelines to transport captured CO2, which already have some environmental advocates nervous.

Mammoth is still very much in its infancy. Construction is expected to take place over the next 18 to 24 months.