Pioneering ‘fingerprint’ test will build confidence in geological storage of CO2
A test developed by Scottish scientists to check for leaks from carbon capture and storage (CCS) sites, where man-made carbon dioxide (CO2) emissions are stored deep underground, has been used for the first time in Canada.
Researchers from Scottish Carbon Capture & Storage (SCCS) have developed a way to measure tiny traces of inactive natural gases, known as noble gases, found in CO2. These noble gases vary depending on whether the CO2 is from just below ground or deep below, enabling scientists to fingerprint a sample and pinpoint its source.
The technique, developed by scientists at the University of Edinburgh, has been conclusively used to investigate an alleged leak from CO2 injected underground at a farm in Saskatchewan, Canada. The test showed that high levels of CO2 recorded on the farm arose from nearby wetlands and were not leaking from a CCS site at the nearby Weyburn Oil Field.
While studies have shown that small amounts of CO2 seepage carry no significant threat to human health, the new test will allow scientists and storage site developers to reassure residents that CO2 storage sites are secure.
The technique will be useful in countries, such as Canada and the USA, where onshore CO2 storage is already underway. In the UK, which has ample offshore CO2 storage, scientists are researching how this test can be combined with other offshore monitoring methods.
Dr Stuart Gilfillan of the University of Edinburgh’s School of GeoSciences, who led the study, said: “Carbon capture and storage is an essential means to curb emissions of greenhouse gases, which is needed to limit global warming to 2°C, as internationally agreed recently in Paris. Securely storing captured CO2 is critical to its success and our method of identifying any leaks should give assurance to local communities. Our work provides a simple way to easily and unambiguously spot leaks from future storage sites, using the fingerprint of noble gases that the CO2 picks up during storage.”
The study has been published in the International Journal of Greenhouse Gas Control and was funded by the Natural Environment Research Council and SCCS.