The windswept valleys surrounding the Hengill volcano in southwestern Iceland are dotted with hot springs and steam vents. Hikers from all over the world come here to witness its breath-taking scenery. Even the sheep are photogenic in the soft Nordic light.
Right in the middle of all that natural beauty sits a towering metal structure resembling four giant Lego bricks, with two rows of six whirring fans running across each one. It’s a contraption that looks truly futuristic, like something straight out of a sci-fi film.
Humans have emitted so much carbon dioxide (CO2) into the atmosphere that machines like this are being used to literally suck the gas back out, like giant vacuum cleaners, in an attempt to slow the climate crisis and prevent some of its most devastating consequences.
The Orca plant — its name derived from the Icelandic word for energy — is what is known as a “direct air carbon capture facility,” and its creator and operator, Swiss firm Climeworks, say it’s the world’s largest.
The aim of Orca is to help the world reach net zero emissions — where we remove as much greenhouse gas from the atmosphere as we emit. Scientists say that simply cutting back on our use of fossil fuels won’t be enough to avert catastrophe; we need to also clean up some of the mess we’ve been making for hundreds of years.
Orca is a depressing symbol of just how bad things have become, but equally, it could be the tech that helps humanity claw its way out of the crisis.
“We, as humans, have disturbed the balance of the natural carbon cycle. So it’s our job to restore the balance,” said Edda Aradóttir, a chemical engineer and the CEO of the Icelandic company Carbfix, which carries out a process to store the captured CO2 underground.
“We are assisting the natural carbon cycle to find its previous balance, so for me, at least, this makes total sense — but we have to use it wisely,” she said.
It opened last month and currently removes about 10 metric tons of CO2 every day, which is roughly the the same amount of carbon emitted by 800 cars a day in the US. It’s also about the same amount of carbon 500 trees could soak up in a year.
It’s a fine start, but in the grand scheme of things, its impact so far is miniscule. Humans emit around 35 billion tons of greenhouse gas a year through the cars we drive and flights we take, the power we use to heat our homes and the food — in particular the meat — that we eat, among other activities.
All this CO2 accumulates in the in the air, where it acts like the glass of a greenhouse, trapping more heat in the atmosphere than Earth has evolved to tolerate.
That’s where the technology used for Orca, called carbon capture and storage (CCS), comes in.
“Carbon capture and storage is not going to be the solution to climate change,” Sandra Ósk Snæbjörnsdóttir, a geologist with Carbfix, told CNN.
“But it is a solution. And it’s one of the many solutions that we need to implement to be able to achieve this big goal that we have to reach.”
She added: “First and foremost, we have to stop emitting CO2 and we have to stop burning fossil fuels, the main source of CO2 emissions to our atmosphere.”
How the ‘magic’ happens
The Orca machines use chemical filters to capture the heat-trapping gas. The “fans,” or metal collectors, suck in the surrounding air and filter out the CO2 so it can be stored.
Carbon dioxide’s concentration in Earth’s atmosphere has likely not been this high at any other point in the last 3 million years, according to NASA scientists. But at levels over 410 parts per million, to actually capture a meaningful amount of CO2, a huge amount of air needs to pass through these machines.
“What is happening is that CO2 in the air is an acid molecule and inside the collectors we have alkaline. Acids and alkaline neutralize each other,” Climeworks co-CEO Christoph Gebald told CNN. “That’s the magic that happens.”
In two to four hours, the surface of the filter is almost completely saturated with CO2 molecules — as if there are “no parking slots left,” as Gebald puts it.
“Then we stop the airflow and we heat the internal structure to roughly 100 degrees Celsius, and at that temperature, the CO2 molecules are released again from the surface, they jump off back to the gas phase and we suck it out.”
Because of the high temperature that is needed for the process, the Orca plant requires a lot of energy. That’s a problem that’s easily solved in Iceland, where green geothermal power is abundant. But it could become a challenge to scale globally.
The machines at Orca are just one way to remove CO2 from the air. Other methods involve capturing the gas at source — like the chimney of a cement factory — or removing it from the fuel before combustion. That involves exposing the fuel, such as coal or natural gas, to oxygen or steam under high temperature and pressure to convert it into a mixture of hydrogen and CO2. The hydrogen is then separated and can be burned with much lower carbon emissions. However, methane emissions could be a problem when the process is used on natural gas.
The carbon that comes out of CCS can be used for other purposes, for example to make objects out of plastic instead of using oil, or in the food industry, which uses CO2 to put the fizz in drinks. But the amount that needs to be captured vastly exceeds the world’s demand for CO2 in other places, which means the majority of it will need to be “stored.”
At Orca, this happens just a few hundred meters away from its vacuum in several igloo-like structures where the gas is mixed with water and injected around 800 meters underground. There, the CO2 reacts with sponge-like volcanic rocks and mineralizes, while the water flows away.
Emissions crisis
The latest state-of-the-science report by the Intergovernmental Panel on Climate Change (IPCC) showed that the world needs to cut greenhouse gas emissions in half over the next decade and achieve net zero by 2050 to have any chance of keeping global warming to 1.5 degrees Celsius above pre-industrial levels.
The higher temperatures rise beyond 1.5 degrees, the more the world will experience an increase in extreme weather events — both in strength and frequency — like droughts, hurricanes, floods and heatwaves.
CCS technology sounds like the perfect solution, but it remains highly controversial, and not just because of the amount of energy it needs. Its critics say the world should be aiming for zero emissions, not net zero.
But scientific consensus is pretty clear: some level of carbon capture will soon become necessary. The IPCC estimated that even if emissions decline dramatically, to keep temperature increases below 2 degrees will require the removal of between 10 billion and 20 billion tonnes of CO2 every year until 2100.
“I don’t think carbon capture is a silver bullet, because there is no silver bullet,” said Nadine Mustafa, a researcher that specializes in carbon capture at the department of chemical engineering at Imperial College London, and is not involved with Orca.
“It’s not that we are going to fix everything by using renewables, or that we’re going to use carbon capture and storage and we’re going to fix everything with that. We’re going to need everything, especially because we’re already behind on our goals.”
The oil and gas link
Opponents of CCS argue the technology is simply another way for the fossil fuel industry to delay its inevitable demise.
While they are not involved in the Orca plant, fossil fuel giants dominate the sector. According to a database complied by the Global CCS Institute, a pro-CCS think tank, an overwhelming majority of the world’s 89 CCS projects that are currently in operation, being built or in advanced stages of development are operated by oil, gas and coal companies.
Oil companies have had and used the technology to capture carbon for decades, but they haven’t exactly done it to reduce emissions — ironically, their motivation has been to extract even more oil. That’s because the CO2 they remove can be re-injected into oil fields that are nearly depleted, and help squeeze out 30-60% more oil than with normal methods. The process is known as “enhanced oil recovery” and it is one of the main reasons why CCS remains controversial.
Fossil fuel companies are also investing in the newer carbon capture tech that removes CO2 from the air — like Orca’s machines do — so they can argue they are “offsetting” the emissions that they can’t capture in their usual processes. It’s one way to delay fossil fuels’ inevitable demise as the world transitions to renewable energy sources.
There is another way to look at it.
Fossil fuel companies have the big bucks to invest in this expensive tech, and considering fossil fuels are by far the main driver of climate change, it can be argued that they have a responsibility to foot the bill for what could be the biggest environmental disaster clean-up in human history.
The global fossil fuel industry is worth trillions of dollars. In 2019, the last year before the pandemic, publicly listed fossil fuel companies raked in $250 billion in profits, according to data compiled for CNN by Refinitiv. That figure doesn’t include Saudi Aramco, the world’s biggest oil company, which was not publicly listed until December 2019. On its own, the company made $88 billion that year.
“This is a group who could transition to providing this service to society at large,” said Graeme Sweeney, chairman of the Zero Emissions Platform (ZEP), which is one of the more powerful advocates for CCS in Europe. The group acts as an advisor to the European Commission, from which it also receives part of its funding, and comprises research groups, the European Trade Union Confederation, as well as many of the world’s biggest oil companies, including Shell, Total, Equinor, ExxonMobil and BP.
The way Sweeney sees it, providing this tech could even be a chance for the fossil fuel industry to begin to atone for the climate crisis.
“It would be, in a sense, odd, if that was not the contribution that they made,” said Sweeney, who previously worked for Shell for three decades.
Asked whether CCS should be used to allow more fossil fuel production in the future — something climate activists worry about — Sweeney said: “If we regulate this appropriately, then it will produce an outcome which is compatible with net zero in 2050 … what’s the problem?”
One remaining risk in this technology is the impact that storing the carbon may have on the Earth, or at least its immediate environment. In its special report on carbon capture and storage, the IPCC said that by far the biggest risk comes from potential leaks. A sudden and large release of CO2 would be extremely dangerous. In the air, a CO2 concentration of around 10% is deadly, but even much lower levels can cause health issues.
It’s a massive risk to take.
But the idea of using deep sea storage is not new and it has been used for some time. At Sleipner, a gas field in Norway, CO2 has been injected underground since 1996. The site has been monitored closely, and apart from some issues during the first year, it has not shown any problems in its 25 years running.
Snæbjörnsdóttir, who heads the CO2 mineral storage at Carbfix for Orca, said the mineralization process they use in Iceland eliminates the risk of leaks. And the basalt — which is volcanic rock — around the plant makes for an ideal geological storage.
“These rocks are very permeable, so they are kind of like a sponge, and you have a lot of fractures for the CO2-charged fluid to flow through, so it mineralizes quite rapidly,” Snæbjörnsdóttir said.
Standing next to the injection site, Snæbjörnsdóttir grabbed a piece of crystallized calcium carbonate, known here as the Icelandic spar, and held it against the sunlight. “This is nature’s way of turning CO2 into stone, in its most beautiful way,” she said as tiny reflections of light from the rock danced on the walls around her.
“Once you have mineralized the CO2, it stays there forever.”
