Carbon Capture and Storage (CCS) could reduce fossil fuels' contribution to climate change by capturing carbon dioxide (CO₂) emissions at source and storing them underground in geologically sound locations. However, measurements are required to ensure that the CO₂ emissions do not leak back into the atmosphere during this process.

NPL, as a world leader in atmospheric measurements, is perfectly placed to develop a range of techniques to detect these fugitive emissions:

Optical measurements

NPL's Differential Absorption Lidar (DIAL) facility can provide rapid, accurate measurements of airborne emissions, up to 3 km away, and use these to generate a 3D emissions map (see image). This means that it can not only detect leaks, but also locate their source.

Other optical techniques suitable for long term emissions monitoring over wide areas include tuneable diode lasers, Fourier Transform Infrared Spectroscopy (FTIR) and broadband sources.

Acoustic techniques

NPL's expertise in underwater acoustics could assist with monitoring CCS sites located under the seabed, such as those in depleted oil and gas reservoirs.

The scattering of sound by bubbles of the leaked CO₂ gas can be detected using imaging or sub bottom profiling sonar, while geoacoustic sensors placed on the sea floor could detect movement caused by subsidence, providing early warning of changes to the shape of the seabed.

Measuring pH

Another useful technique is a pH test because the release of CO₂ from an underwater storage facility would make the surrounding water more acidic.

As these measurements need to be made in situ, using novel devices that can withstand high pressures, NPL's primary pH measurements would be essential for ensuring the validity and traceability of the collected data.

These techniques could all play a part in the successful implementation of CCS. NPL can make a significant contribution by both validating the methodologies and providing the necessary expertise for making the measurements themselves.

For more information, please contact Heather Powell or Rod Robinson