Latest research by Duke University has found that underground storage of injected CO2 could potentially increase contamination levels in water aquifers as much as tenfold. Core samples were gathered from freshwater aquifers around America that provide potable water supplies and which also lie over the top of sites identified as suitable for potential carbon capture and storage (CCS) projects.
Scientists put the samples through a range of tests and found that in some cases the CO2 leaking into the water increased the contaminant loads above that set by the U.S Environmental Protection Agency's levels for drinking water.
The results of the study have the potential to significantly impact many of the CCS projects, including geosequestration, that are currently underway around the world. Geosequestration is where CO2 from major industrial sources is stored deep below the earth's surface. This approach plays a major part in CCS investigations for reducing the impacts of climate change by minimising the greenhouse gas emissions that make their way into the atmosphere.
The Cooperative Research Centre for Greenhouse Gas Technologies in Australia, one of the world's leading collaborative CCS research organisations, says that geosequestration represents perhaps the only option for decreasing greenhouse gas emissions while using fossil fuels and retaining our existing energy-distribution infrastructure. It is understood that the U.S Department of Energy has at least seven CCS projects on their books.
Professor Robert Jackson at the Duke University's Center on Global Change said that "based on a year-long analysis of core samples .... we found the potential for contamination is real, but there are ways to avoid or reduce the risk". He stresses that through the research they have identified certain geological criteria which means at risk locations could be identified, but that not all sites would be susceptible to drinking water contamination.
According to Professor Jackson, fear of contamination of drinking water by leaking CO2 is one of the main reasons for local communities to oppose CCS projects. This new research might just help to identify which projects are more at risk than others.