The science behind carbon capture and storage (CCS) may have reached a turning point with the new announcement that the process of injecting liquid CO2 into underground basalt formations has proven successful in the field.
Back in 2013, researchers with the US Department of Energy’s Pacific Northwest National Laboratory injected 1,000 tonnes of liquid carbon dioxide into a natural basalt formation in eastern Washington state and then spent the next two years monitoring the site before taking up core samples. Now, in a new study published in the journal Environmental Science and Technology Letters, researchers have shown that the core samples turned out to be a veritable CCS jackpot, as the injected CO2 had been itself transformed into stable, solid carbonate – and in a timespan much quicker than predicted.
“We’d seen these things in the lab, but the field is often a case where your best laid plans and ideas from lab experiments fall apart and just don’t work out,” says Peter McGrail, principal investigator with Pacific Northwest Labs, in conversation with the Washington Post. “And the fact now that we’ve seen this after just two years with the exact really same things that we’ve seen in the laboratory, it’s a really significant result for us.”
Found all over the world, basalt rock forms from volcanic lava that flowed millions of year ago, with one of its properties being that it can react with CO2, converting it into stable carbonate rock. The new results show that rapid mineralization of CO2 in reactive basalts actually works in the field and thus that large-scale underground injection of C02 is a real possibility for long-term CO2 storage.
“There is a real value in being sure that storage is permanent on a geological time scale and that the carbon does not need any further monitoring,” says McGrail. “Once you made carbonate there is no reason why it would revert again. You hit the thermodynamic ground state and it is very difficult to dislodge it from there.”
The research doubles up on results obtained earlier this year by a team of scientists working on the CarbFix project in Iceland – an island which is itself composed of 90 per cent basalt rock – where researchers successfully stored 250 tonnes of CO2 dissolved in water in basalt rock formations. The team found that in two years, over 95 per cent of the injected carbon dioxide had mineralized.
Many assume that CCS will be a critical component to any concerted worldwide effort at combating climate change. Targets set by the International Panel on Climate Change (IPCC)’s already involve considerable “negative emissions” -i.e., captured and stored CO2- in order to keep global warming below two degrees Celsius.
With Canada’s just-announced plan to phase out coal power by 2030, the push will be for power plants to meet higher emissions standards, likely requiring the adoption of CCS technology in some form. Currently, coal power makes up about eight per cent of Canada’s greenhouse gas emissions and produces about 11 per cent of the country’s electricity, according to a report by the Pembina Institute.