A business case is materialising at a carbon capture project in Iceland that could help reduce the amount of harmful
particles in the atmosphere
ROCK SOLID
Current carbon storage techniques require constant monitoring. Converting the gas into solid rock reduces this need
SHIPPING CONCERNS
A global trade network for carbon could materialise so it can be transported to where storage makes the most sense
KEY QUOTE
Mineralisation is a permanent storage solution. We are not putting CO2 in a cave and monitoring if it comes out. We are changing the CO2 into rock
In Iceland, carbon sequestering startup Carbfix is gearing up for a decarbonisation boom by storing CO2 as crystals in porous rocks—cited as a permanent solution to increasing levels of climate-altering carbon with no monitoring costs. The first containers have just been imported and the technology is almost ready to take on the rest of the world. On a craggy, moss-ridden volcanic plain to the southeast of Iceland’s capital Reykjavik, unnatural clouds of mist blanket the hills. The clouds and the pervasive smell of rotten eggs are evidence of Hellisheiði, a 300 megawatt (MW) geothermal power plant comprising a sleek modern structure looking more like an office building than an electricity generator. The site is the nexus of a sustainability wonderland in Iceland. Next door lies Swiss carbon-capturing company Climeworks and Israeli-owned algae greenhouse Vaxa Life. Besides these more well-known projects is a small and unimpressive geodesic dome of aluminium. This is one of Carbfix’s injection wells, which pumps carbonated water deep underground as a means to store carbon dioxide (CO2). The injected water is similar to the sparkling water you can buy at the store or have in a restaurant—just with a much higher concentration of CO2. “The sparkling water is pumped into porous basaltic rocks and the CO2 combines with the rock to form new minerals or crystals. Two-thirds of the CO2 is mineralised in two months and 99% within a year,” says Karí Helgason from Carbfix over a loud hissing from the well. Outside the dome, pressurised shipping containers marked “CO2” are stacked next to the dome. They signal the next step in what could well be the beginning of a huge mineralisation boom in Iceland and elsewhere.
DIRECT AIR CAPTURE The Carbfix project is located next to the Climeworks direct air capture project
HISTORIC PROBLEM
As the recent COP27 climate negotiations in Egypt proved once again, getting rid of fossil fuels from the energy mix is quite challenging. Global emissions have plateaued but are yet to be on a downward trajectory. But even if the transition away from fossil fuels succeeds, and the level of carbon being emitted is reduced, we are left with a problem: There is still a huge excess of historic carbon dioxide in the atmosphere, emitted over the past 200 years. This needs to be removed or temperatures continue to rise. Natural processes do remove the carbon through “weathering”, where CO2 reacts chemically with rocks, turning it into new minerals but this process takes a long time. “We measured this,” says Sigurdur Reynir Gislason from the University of Iceland. “The response time is around one million years. So it is not going to save us.”
ACCELERATED WEATHERING
One avenue being explored to accelerate this process is mineralisation technology, which Gislason helped develop along with, among others, American climate scientist Wallace Broecker, who coined the term “global warming”. Gislason’s former and current students developed this idea into the “Carbfix method” and many of those students run the company today. “We are taking this natural weathering and we are speeding it up by injecting the water into the rock at high pressure. I call it the soda stream machine,” Gislason jokes. He pores through old issues of Elements and Geophysics Review to find a picture of the early days. The Carbfix method was first launched in experimentation in 2007 and is now mineralising CO2 at an industrial scale of 17,000 tons every year. Most of the CO2 currently being injected stems from the geothermal generation project next door, where carbon dioxide follows the hot water up from the depths below. The rest is captured by Climeworks from the atmosphere. Both sources of CO2 are added to Gislason’s “soda stream” machine and injected 800 meters down where the CO2 crystallises and the water heats up again—ready to return to the geothermal power plant on the surface. According to Carbfix, there is theoretically enough basalt in Iceland to store all the world’s excess CO2. “One cubic meter of rock can store 100 kilograms of CO2. So the capacity is enormous,” explains Helgason from Carbfix.
FOSSIL FUELLED WOES
Capturing CO2 from the atmosphere is not a new idea; trees and other plants have been doing exactly that for millennia. But Earth cannot sustain enough trees to remove enough of the climate change-inducing carbon dioxide from the atmosphere. To support this, companies and governments are investigating technological solutions to carbon capture and storage. Traditionally, this has involved pumping the CO2 underground into already existing pore networks in sedimentary layers, often where the extraction of natural gas and oil has occurred and then putting a capstone on the well. The problem is most CO2 storage projects are actually so-called Enhanced Oil Recovery, explains Peter Kelemen from Lamont-Doherty Earth Observatory at Columbia University in the United States. Enhanced Oil Recovery uses CO2 gas to push every last drop of oil and gas out of existing fields, adding to future emissions. “The amount CO2 stored is increasing by 8.3% per year, but more than 90% of that has been for EOR. We are very far from meeting targets,” he says. This method is also partly responsible for the slow adaptation of Carbfix’s mineralisation technology, Kelemen believes. The fossil industry already understands and has experience with Enhanced Oil Recovery techniques so is less willing to try new techniques. Only two pure CO2-storage wells have been approved in the US to date, while lots of wells are approved for the purpose of injecting CO2 for EOR.
MONITORING COSTS
Apart from being used to increase extraction of fossil fuels, traditional carbon storage technologies have another issue, explains Susan Stipp from the Technical University of Denmark (DTU) who specialises in carbon mineralisation. “Supercritical CO2 [liquid carbon dioxide at high temperature and pressure] is buoyant. It wants to go to the surface. CO2 stored in unreactive rocks can take 1000-10,000 years or longer to convert to solids,” she says. Monitoring these reserves for potential leaks is expensive. Especially because carbon storage projects are mainly offshore, using old oil and gas wells, which means the monitoring has to be done by ships. The need for such monitoring with mineralisation techniques is far less. “It is important to understand that mineralisation is a permanent storage solution. We are not putting CO2 in a cave and monitoring if it comes out. We are changing the CO2 into rock,” says Carbfix’s Kristinn Ingi Lárusson. Carbfix claims the whole value chain, from capturing to transporting and mineralising the CO2, costs less than $25 per ton, lower than recent carbon tax prices. “We believe we have a good business case,” Lárusson adds.
FUTURE TRADE Carbfix believes an international trade market for carbon could be established
BUSINESS SENSE
Currently, Carbfix is charging a fee for the storage of CO2 from the geothermal power plant and for the CO2 being captured by the Climeworks’ Orca plant but can see how regulatory instruments can support a future carbon trading market. “There is already a market for this. The Emissions Trading System sets the price right now. But this is only the beginning. With time other avenues will hopefully open up,” explains Lárusson. Energy Program Chief Scientist at Lawrence Livermore National Laboratory, Roger Aines agrees but has a few caveats: “The Carbfix process is quite economic, given a source of pure CO2, lots and lots of water and reactive basalt, which probably means [it’s] reasonably fresh,” he says. Fresh basalt is volcanic lava which has recently cooled into rock—recently in geological terms could still mean thousands if not millions of years old. The Carbfix method does need enormous amounts of water; 25 tonnes for each tonne of CO2 to be precise, explains Gislason of the University of Iceland. A solution is to carbonate seawater and inject that instead of potable water. “The weakness of Carbfix is the amount of water needed. You don’t have that water in central India or in Oman, so now they are studying a way to use seawater,” he says. The access to seawater is one of the reasons Carbfix are currently building its CODA Terminal south of Reykjavik on the west coast of Iceland, which will be the largest mineralisation storage site in the world. The CODA Terminal is also part of a large industrial harbour, shipping out aluminium from the Rio Tinto smelting plant next door. But other ships will soon be arriving, Carbfix hopes, with containers of CO2. “Is shipping CO2 there, or doing Direct Air Capture, going to meet the supply? For that we have to consider not today’s fossil economy, but rather the options for removing and storing CO2 in a net-zero world,” Aines says.
CARBON IMPORTS
Back to the pressurised shipping containers marked “CO2” stacked outside the Carbfix injection well. They contain pure CO2 captured at a water treatment plant in Switzerland, transported to Iceland by ship and to be injected using seawater into the seabed off the west coast of Iceland. If the trial works, Carbfix will be able to expand its method to other basalt-rich locations, without access to plentiful fresh water, such as India or Saudi Arabia. However, the biggest obstacle for Carbfix is the transport of carbon dioxide to the mineralisation sites. “Transport of CO2 to Iceland is a key issue. Direct Air Capture in Iceland will always be expensive—as it will be anywhere—but the world needs these solutions,” says Aines. “Cleaning up the air is like taking out the trash—we will all have to pay to have the environment we want, but the mechanisms by which we pay for trash collection, and air cleanup, will vary a lot,” he adds. “In California, we spend 3% of our GDP on managing trash—that amount worldwide would easily pay for the needed carbon dioxide removal at hundreds of dollars per ton. It is a choice we will have to make,” Aines adds. He believes Iceland has a leg up when it comes to importing CO2, because of its proximity to both Europe and North America.
PUMPED STORAGE
The carbonated water is injected underground which then reacts with the rock to mineralise and store the carbon
TECHNOLOGY EXPORTS
Carbfix is unconvinced with large-scale importing of CO2 from abroad fearing that Iceland might not take too kindly to the prospect of being the world’s CO2 dumping ground, even if it is turned into rock. This is why its Coda Terminal is placed right next to the Rio Tinto aluminium smelting plant. The Anglo-Australian metals and mining firm is their preferred type of customer: one which produces a lot of CO2, a point source or single localised emitter, with few other ways to reduce emissions and is willing to pay Carbfix to solve its emissions problem. “The most economically efficient way to mineralise is to do it on-site, close to the emitter,” says Lárusson, which is why Carbfix is identifying these emitters and ideally wants to come to them to inject the CO2 nearby. Carbfix can map the local geology to see if the technology can be used near the emitter. But there is a catch.
BASALT IS NOT JUST BASALT
Basalt is found almost everywhere on the globe and on the seabed of 70% of the world’s oceans, explains Gislason. But it has to be the right type of basalt for the mineralisation to just work. “The method works well in Iceland because the rocks are fresh and still warm there. They have many edges for the water to react with. The older the basalt, the more it has already reacted,” and is, therefore, less effective in trapping the carbon, says DTU’s Stipp. There are ways to change this. Stipp is leading a research team in Denmark focusing on getting older basalt to react more quickly and researching ways of controlling the chemistry occurring in the injection. Carbfix is confident its technology will work away from Iceland—but the process might take a bit longer. “We know it works on an industrial scale. But you have only one chance to do a first impression. This is why we have always been very transparent and cautious. We want to show the world that this is possible and then license the technology out,” Lárusson says. By the end of 2023, Carbfix wants to have activity across all continents. “We want to receive and mineralise one billion tonnes as soon as possible. Hopefully before 2035,” Lárusson says.
THE CARBON ECONOMY
Carbfix hopes the world’s lawmakers and chief executives will soon take the issue of excess carbon seriously and eventually have the courage to move away from cap and trade systems. “What is needed is a global umbrella around climate issues. We have the ETS [in Europe], but if we had a global carbon tax that would be better. The biggest challenge is policy and lawmakers. They are slow movers and we are in a hurry,” Lárusson says. “We have a technology, we do not claim to have the only technology. Other technologies are fine as well. We need it all. Store CO2 in old reservoirs, whatever. The volume is so great that we can’t wait. We need to do everything. But we do acknowledge that it could be quite the economic adventure,” he adds. Kelemen at Columbia University agrees there will be plenty of business to go around no matter the carbon removal technology. “We are told that by 2050, to hold global warming to less than 2℃ from pre-industrial levels, in addition to installing carbon capture at all remaining point sources of CO2 and methane probably comprising over ten gigatonnes of CO2- equivalents, we need to remove another ten gigatonnes of CO2 from the air every year,” he says. Some of those emissions might be stored in soil and in the oceans, but the remainder should be geological storage, he adds. “So, pick your favourite number, say around $20/tonne for storage by mineralisation. Now multiply that by over 20 gigatonne yields. That’s over $400 billion per year. Is this realistic? Well, the world spends more than two trillion dollars every year on solid waste management and sewage treatment,” he concludes. •
TEXT Søren Bjørn-Hansen