Quantification of dissolved CO2 plumes at the Goldeneye CO2-release experiment

According to many prognostic scenarios by the Intergovernmental Panel on Climate Change (IPCC), a scaling-up of carbon dioxide (CO2) capture and storage (CCS) by several orders-of-magnitude is necessary to meet the target of <2 degrees C global warming by 2100 relative to preindustrial levels. Since a large fraction of the predicted CO2 storage capacity lies offshore, there is a pressing need to develop field-tested methods to detect and quantify potential leaks in the marine environment. Here, we combine field measurements with numerical models to determine the flow rate of a controlled release of CO2 in a shallow marine setting at about 119 m water depth in the North Sea. In this experiment, CO2 was injected into the sediment at 3 m depth at 143 kg d-1. The new leakage monitoring tool predicts that 91 kg d-1 of CO2 escaped across the seafloor, and that 51 kg d-1 of CO2 were retained in the sediment, in agreement with independent field estimates. The new approach relies mostly on field data collected from ship-deployed technology (towed sensors, Acoustic Doppler current profiler-ADCP), which makes it a promising tool to monitor existing and upcoming offshore CO2 storage sites and to detect and quantify potential CO2 leakage.

Automated summary

Scaling up CO2 capture and storage is essential to limit global warming to below 2 degrees Celsius, with a focus on detecting and quantifying potential leaks in offshore environments. Combining field measurements and numerical models can accurately monitor CO2 leakage and retention in marine settings.