Experiment to Study CCS Storage Site Leak Effect Successfully Completed

The critical stage of an experiment that was carried out for the first time to monitor what might happen if CO2 leaks from an underground storage reservoir has been successfully completed.

Following a complex drilling operation, the injection of CO2 from a shore-based laboratory into shallow marine sediments is allowing scientists to determine whether (and how) such a leak from a CCS sub-seabed storage site would adversely affect marine life.

The tests have also enabled assessment of various ways of monitoring CO2 leakage. As the world searches for viable climate change mitigation strategies, the approach of carbon capture and storage (CCS) is one method that is attracting significant international attention and is emerging as one of the frontrunners for tackling climate change.

CCS is the process by which CO2 is captured from power plants and industrial actions before it is emitted into the atmosphere and then pumped into deep sub-seabed reservoirs or geological structures for permanent storing. The risk of leakage from storage sites is thought to be low, but, it is vitally important to thoroughly investigate the benefits and risks of potential mitigation strategies early in their development.

One such research project is the Quantifying and Monitoring Potential Ecosystem Impacts of Geological Carbon Storage (QICS) led by Plymouth Marine Laboratory in collaboration with the Scottish Association for Marine Science and four other institutions.

The project's primary experiment is a world-first and has been releasing moderate levels of CO2 into shallow sediments in a Scottish Bay, enabling scientists to study the progress and effects of a controlled CO2 leak and extrapolate these to real-life situations, which might occur in the future.

"The experiment is going exactly to plan and we are very pleased so far. We are now at the stage of collecting detailed data which will enable us to get closer to predicting what might happen if a real leak occurred on an active storage site. As well as looking for environmental impacts the experiment has allowed us to test a range of monitoring equipment in a real world setting," project leader Jerry Blackford from Plymouth Marine Laboratory stated.

For the last 30 days CO2 has been supplied from a "pop-up" lab and passed through a borehole under the sediment to the release site, 350 metres from the shore and 12 metres below the seabed of Ardmucknish Bay near Oban. Initial results have shown that the first two phases of the project (construction and CO2 release) have been successful and that the CO2 "behaved" as expected. Localised impacts had been anticipated and divers visiting the site have observed that some creatures are affected while others remain unaffected.