Rock solid solution to greenhouse gases John Ingham
GIANT silver golf balls sitting in the middle of a barren, rocky Martian landscape, steam rising all around. You feel like you have strayed on to the set of StarWars.
But this pioneering science fiction project at Hellisheidi, 30 minutes outside Reykjavik, is far removed from Hollywood fantasy. And it offers hope for a world facing a climate catastrophe because it is turning greenhouse gas carbon dioxide into stone.
It is one of the first carbon capture and storage systems to show true promise and, according to University of Iceland geochemist Dr Martin Voigt, the potential is vast and global.
Martin, 34, works with the company Carbfix, which has already pumped 70,000 tons of CO2 into Iceland’s volcanic rocks since 2014.
The gas, which is dissolved in water, reacts with natural minerals to form tough calcite, locking it underground for ever. Carbfix’s estimate of the potential is staggering. It says: “The global storage potential is greater than the emissions of the burning of all fossil fuels on Earth.
“It is estimated that Europe could theoretically store at least 4,000 billion tons of CO2 in rocks, while the United States could store at least 7,500 billion tons.”
To put that in context, global CO2 emissions last year were about 34 billion tons.
We saw the CO2 stored in a sample of the grey volcanic rock – basalt – whose pores had become speckled with white calcite.
Virtually the whole of Iceland is volcanic rock – and so far Carbfix has exploited just 0.01 per cent of the potential storage space.
The firm now wants to increase operations from 12,000 tons of CO2 a year to three million. From 2025, it plans to capture CO2 at overseas factories, take it to Iceland in liquid form on renewable energy-powered ships, then petrify it in the lunarlike landscape near Keflavik airport.
Martin, originally from Stuttgart, Germany, said: “This won’t be the only solution to climate change. We will need a lot of solutions and Carbfix is one of them. We still need to reduce emissions altogether.
“But for a lot of businesses it is cheaper and more efficient to capture CO2 and store it underground safely.
“If you look at how much basalt we have in Iceland, that could easily store all the greenhouse gas emissions targeted by the Paris Climate Agreement. But basalt occurs all over the world. Virtually all the ocean floor is basalt and what Carbfix needs to work is CO2, basalt and water. I researched into this and found you can use seawater for the Carbfix process.” The cost works out at about £18 a ton of CO2 compared with £44 a ton under carbon trading schemes, where firms basically pay a tax on the greenhouse gas. Martin said: “It’s a win-win. Firms save money and they do not emit the greenhouse gas.”
The system began at Hellisheidi, one of the largest geothermal power stations in the world. It tapped into super-hot water from deep beneath an island where earthquake tremors are routine and the Fagradalsfjall volcano is currently spewing out lava near the international airport.
A lot of CO2 and hydrogen sulphide – the gas that smells like bad eggs – is held in the scalding water from deep below Earth. Carbfix removes both in a 42ft scrubbing tower – rather like a giant soda machine – helping the power company avoid pollution taxes.
Martin explained: “It dissolves the gases in the water and purifies it. It’s a bit like making sparkling water.”
The water then flows down a pipeline to the giant golf balls, which cover injection wells whose boreholes go 1.24 miles down into the basalt. Gravity then takes over and the water is released about 800 yards down.
Martin said: “The CO2 in the water reacts very quickly with the basalt. It is slightly acidic and dissolves elements in the basalt such as calcium, magnesium and iron and forms a carbonate mineral, calcite, which keeps the CO2 in its structure.
“The gas becomes solid and is permanently and safely stored in rock form.
“The process starts within days. After three months 60 per cent of the CO2 is mineralised.”
Other methods of carbon capture and storage being explored by companies include pumping CO2 into old North Sea oil and gas fields.
But Martin said: “In the North Sea schemes you have pure CO2 compressed into a liquid and injected into these old oil reservoirs.
“But pure CO2 is less dense than seawater so a cap has to be built to prevent leaks.
“At Carbfix, the CO2 dissolved in water is more dense than the surrounding water underground so there is no worry about it coming back up. It makes it much safer.”
John Ingham and Jonathan Buckmaster offset the greenhouse gases from their return flights to Iceland with C Level Earth – clevel.co.uk