On May 8, the Hellisheiði Power Station in Hengill, Iceland, witnessed the opening of Mammoth, the world’s largest direct air capture (DAC) plant. Each year, Mammoth will remove 36,000 tons of carbon from Earth’s atmosphere. This is equal to eliminating the pollution that 7,800 gas cars produce annually. 

A DAC plant alone can’t save us from the ongoing climate crisis, but this technology addresses an important issue related to the high levels of carbon in our atmosphere. Many people believe that we can reverse climate change just by focusing on reducing our carbon emissions, but what about all the extra carbon we’ve already released into the atmosphere? 

According to the International Energy Agency (IEA), if humans are really serious about meeting their climate goals, they’ll have to figure out a way to remove 70 million tons of carbon annually by 2030, in addition to reducing their carbon emissions. 

“Cutting back on our carbon emissions alone won’t reverse the growing impacts of climate change. We also need to remove the CO2 that we’ve already put in the atmosphere,” Jennifer Granholm, the US Energy Secretary, said.

This is where DAC plants like Mammoth can play a significant role.

How does a DAC plant work?

A DAC plant sucks in large volumes of air using numerous blowers. The air is then treated with specialized chemicals, called sorbents or absorbents, which selectively capture carbon dioxide (CO2) molecules from the air. 

While the filtered air, now free of CO2 and other contaminants, is released back into the atmosphere, the captured carbon is stored underground. The stored carbon can be used for producing synthetic fuel, construction material, and various other products. But preferably, the stored carbon stays put somewhere.

Mammoth is the largest DAC plant but it’s not the first. In September 2021, Climeworks, the company that built Mammoth installed the world’s first large-scale DAC plant, Orca. This plant is also located at the Hellisheiði Power Station.

Orca, with its eight CO2 collector containers (large chambers where the carbon filtration process takes place), eliminates 4,000 tons of carbon annually. There are currently 17 other active DAC plants in the world, with a combined carbon dioxide removal capacity of 11,000 tons a year. 

Mammoth, on the other hand, comprises 77 CO2 collector containers and is nearly 10 times larger than Orca. It represents a significant advancement, as it alone can remove over three times the CO2 eliminated by all other DAC plants combined.

DACs are a controversial solution

The downsides to many such facilities are that they require large amounts of energy and are highly expensive to set up.

Some DAC operators are suspected of dubious practices. For example, a company named Occidental is building a large DAC plant in Texas. When operational, this facility should eliminate a staggering 500,000 tons of carbon annually. However, their website mentions that the carbon stored from their plant will be used for enhanced oil recovery. This means that they could pump carbon into wells to extract more oil from parts that are currently inaccessible. 

Another aspect to consider is if a company is running its DAC plant using electricity from fossil fuels. That would entirely defeat the purpose. Climeworks claims that this isn’t the case with their plants as both Orca and Mammoth use clean geothermal energy from the Hellisheiði Power Station. 

When it comes to cost, DACs still have a long way to go. Energy experts suggest that to make DACs affordable and feasible on a large scale, they should be able to remove one ton of CO₂ for no more than $100. However, even for Mammoth, the cost is somewhere around $1000 per ton.   

“As the company scales up the size of its plants and bring costs down, the aim is to reach $300 to $350 a ton by 2030 before hitting $100 a ton around 2050,” Jan Wurzbacher, co-founder of Climeworks, said.

The world needs more Mammoths

Mammoth, Orca, and all other active DCA plants in the world will collectively remove 47,000 tons of CO₂ each year from Earth’s atmosphere. This number may sound impressive, but it is nowhere near what we need to achieve to reverse climate change. 

“To maximize our chances of limiting global warming to 1.5 °C above pre-industrial levels, carbon dioxide removal (CDR) solutions such as direct air capture and storage (DAC+S) need to be scaled to gigaton capacity by 2050. To put this into perspective: achieving a DAC capacity of 1 megaton would theoretically require 28 plants similar to Mammoth,” Douglas Chan, chief operating officer at Climeworks, said.

The Climate Clock is ticking fast and clearly, humanity is in dire need of many more carbon dioxide removal solutions like Mammoth. However, we can’t keep on building new DACs without overcoming the challenges associated with them.

Hopefully, in the coming years, scientists will find ways to solve such challenges and devise more advanced and eco-friendly DAC plants.