Developing Environmental Monitoring for Offshore CO2 Storage Projects - One experiment, two ships, lots of measurements means the North Sea in May will be an exciting place!

The STEMM-CCS project held its third annual meeting last week. This is an EU Horizon 2020 funded project that is developing environmental monitoring to test in-situ at a controlled release of CO₂ in the seabed at the Goldeneye location in the North Sea (see IEAGHG 2017-IP14). The project is coordinated by the UK's National Oceanography Centre (NOC), with a consortium of partners representing the leading marine science organisations in the EU and Norway, including GEOMAR, Plymouth Marine Laboratory (PML) and NORCE. IEAGHG is on the Stakeholder Advisory Board.

This third annual meeting was hosted in Amsterdam to review progress over the previous year and to plan the year ahead. The scientific progress across many areas is remarkable, led by the many PhD students working on this. Despite some weather challenges affecting the research cruises and challenges with data retrieval from one of the baseline survey landers, good environmental background data has been collected for the location. This data is already enabling a better understanding of the complexities and variabilities of the environmental baselines in the North Sea, which are changing with climate change, and enabling the development of monitoring strategies for anomaly detection and attribution. The sensors for the range of chemical and physical measurements have been developed or adapted from existing designs, including the small-scale 'lab on a chip' sensor package for nitrate, nitrite, phosphate, pH, alkalinity and dissolved inorganic carbon. These will be deployed on landers, ROVs (remotely operated vehicles) and an AUV (autonomous underwater vehicle).

The project also includes characterisation of offshore pipe and chimney structures and pockmarks (linking with the UK's CHIMNEY project) and has investigated in detail for the first time a pipe structure which allows overburden gases and fluids to permeate through to the seabed, including direct sampling of the pipe geology and matching this with seismic signal interpretation.

Planning is advanced on the engineering and logistics to construct the CO₂ release site at the seabed, and the controlled release is on schedule for May 2019 using the research ships RRS James Cook from NOC and the RV Poseidon from GEOMAR in Germany. James Cook will be used for the experiment construction and near-field monitoring and the Poseidon for the far field monitoring. A research student dedicated to providing media coverage will be on the James Cook, so watch out for tweets and blogs from Ben Roche during May (Ben is also an IEAGHG Summer School alumni from 2018).

The STEMM-CCS project also had good scientific outreach at GHGT-14, with four oral presentations and seven poster presentations, and a popular exhibition stand.

The latest newsletter provides a lot more detail on the release experiment and related work, with articles on baselining the Goldeneye site, engineering a leak, dissecting the anatomy of Scanner Pockmark, optodes for seawater pH measurement, and a guide to measuring bubbles. It can be found at http://www.stemm-ccs.eu/stemm-ccs/sites/stemm-ccs/files/documents/STEMM-CCS_newsletter_Oct18_lowres.pdf .

This is an exciting and unique project that is advancing offshore environmental monitoring, specifically CO₂ leakage detection, attribution and quantification, as well as CO₂ storage site overburden characterisation.

For the cruise prospectus and other and online resources, see http://www.stemm-ccs.eu/ .