ZEP Workshop: ‘CO2 Storage Monitoring: Technologies and Lessons Learned’

Over 140 participants, representing industry, research, and over 20 governments and relevant authorities, attended a one-day workshop organised by the Zero Emissions Platform and European Commission DG Climate Action in Brussels on January 31^st 2025.  The event was focussed on informing CCS regulators from European member states on monitoring of geological CO₂ storage sites.

Organised into three main sessions these covered an overview and background to monitoring plans and technologies, developing and permitting effective monitoring plans, and operating storage sites and handling data.

The day was opened by an introduction and framing from Eadbhard Pernot (ZEP) and Daniel Kitscha (European Commission) setting the scene on the European Industrial Carbon Management (ICM) strategies, and how CCS fits within these. The Net Zero Industry Act has set legal objectives to enable 50 million tonnes of CO₂ to be permanently stored by 2030, with obligations for the oil and gas industry to play their part. In order to gain investor support it’s important to have transparency on the full value chain and potential future storage site options.

In Session One, Tim Dixon (IEAGHG) gave an overview of the environmental and accounting aspects of monitoring of a CO₂ geological storage site, within the framework of the IPCC’s guidelines for greenhouse gas inventories and in the context of global regulations and their objectives using the EU CCS directive as an example. Noting that each monitoring plan is risk based, site specific and not monitoring technology specific. With operational history spanning decades from large-scale and control release experiments there are plentiful resources to learn from. Nikki Clarke (IEAGHG) followed to showcase IEAGHG’s monitoring tool (https://ieaghg.org/monitoring-selection-tool/), a web-enabled decision tool built (2005) and maintained by the BGS every ~3 years. Hosting around 40 monitoring technologies, 26 case studies, and a ranking system that enables decision making via various user informed scenarios. Recent user experience feedback described the monitoring tool as unique resource providing an extensive catalogue of techniques, useful for a sense check and simple to use.

Katherine Romanak (BEG, UT Austin) presented on onshore monitoring, pulling from a wealth of experience from early pilot sites, demonstration sites and industrial projects in the US, many funded through the US DOE Regional Carbon Sequestration and CarbonSAFE programs. Aspects of the monitoring plan include verification that the plume behaviour conforms to predictions and monitoring of the shallow subsurface to assure that there are no unwanted outcomes to the environment. Critical to near-surface monitoring is locating anomalies that could indicate leakage, attributing the source of the anomaly, quantifying emissions and engaging stakeholders. CO₂ has high natural variability which is dynamic in space and time, it is very difficult to discern leakage from natural variability. Therefore attribution (e.g. process-based soil gas ratios), rather than relying on baselines, is an important step to ascertain if the storage project contributed to anomalies, especially in managing project risk. Stakeholder engagement is a key activity, and using examples from Tomakomai and Weyburn Katherine elucidated methods to communicate, verify and allay fears.

Philip Ringrose (NTNU) presented on offshore monitoring technologies and also grounded his talk in the why’s of monitoring, concluding that the next generation of monitoring can be both high-tech and affordable, especially when using fibre-optic technologies and ensuring that you monitor at the right time and in the right place. He explored some of the technical seismic detection limits (dependent on many factors e.g. seismic acquisition plan, depth, porosity, geological architecture) and ways to optimise monitoring systems.  Some of the challenges of imaging deeper layers via 4D seismic (e.g. Sleipner) due to wave interference and velocity pull-down effects have been improved using full waveform inversion (FWI) thereby improving the quantification of the deeper layers. With the scaling up of CO₂ storage in the North Sea, Philip also highlighted a project to measure baseline seismicity (using onshore and offshore geophones, and seabed DAS fibres). The actual risk of induced earthquakes are very low but the concern is that false association of tectonic events is a concern and building trust is imperative.

In Session Two Randy Locke (Illinois State Geological Survey), Kevin Connors (EERC), and Lily Barkau (Wyoming Department of Environmental Quality) spoke about experiences developing monitoring plans in the US. The Illinois Basin Decatur Project has stored ~4.8 million tonnes and the two injection wells were the first Class VI permits grated by the US EPA (although Class I permits were originally sought and approved). Class VI permitting has been in inception since 2010 and Randy walked through the procedure and current status of permit tracker (161 well applications for 56 projects under review). The monitoring summary was presented for the IBDP, showing the extensive range of monitoring technologies deployed  during the demonstration phase and which have been pared down during the industrial injection phase. Both North Dakota and Wyoming, in contrast, have state primacy over Class VI wells and the next two talks discussed approving monitoring plans in these jurisdictions. North Dakota has currently eight storage facility areas, six with planned Class VI wells and three with Class VI wells. Example plans were given and lessons learned explored. In Wyoming a number of projects are in progress and their experience in EOR have helped transition the permitting and compliance to CO₂ wells, yet some uncertainties remain with State and Federal collaboration over pore space.

Ian Barron (NSTA) rounded up the session with the UK perspective of developing (and approving) monitoring plans in the Carbon Storage Licence and post-transfer period. Early risk assessment is a critical component and NSTA works closely with CS licensees to assist in the development of the permit application, and then meet regularly with operators to discuss progress. Each store is considered on a case-by-case basis and they are technology agnostic. The risk profile will vary across the lifecycle of a store.

The final session of the day considered operating storage site and how to handle monitoring data. Philip Ringrose gave an overview of lessons learned from Sleipner, Snohvit and In Salah and then presented the monitoring plans of the Northern Lights storage site (Aurora). Randy Locke followed and dove a little deeper into some of the verification wells at the IBDP and issues around fluid migration. Results from a recent report include recommendations to fully characterise formation fluid in the reservoir and above reservoir prior to injection, and to favour simpler well designs instead of multilevel completions. Both monitoring wells at Decatur have been modified to stop migration above the primary seal.  Katherine Romanak shared learnings from SACROC and Petronova. West Ranch was the first commercial monitoring plan at an EOR field, and showcases how what is implemented for research versus what is implemented for commercial projects differ. At SECARB every technology possible was implemented and then downselected for commercial ends. Early tests included Assessment of Low Probability Material Impacts (ALPMI) i.e. a qualitative assessment of what failure looks like, and in the Above Zone Monitoring Interval (AZMI) – i.e. measure pressure or chemistry. The learnings included environmental monitoring, attribution, stakeholder concerns, and how you evaluate a variety of technologies.  John Hamling (EERC) ended the day with case studies from the Red Trail, Blue Flint and DGC Beulah projects in North Dakota. Covering MMV plans, compliance, reporting, response plans and examples of data driven project design to manage uncertainty (e.g. DAS VSP and Scalable, Automated, Sparse Seismic Array (SASSA)).

There were plenty of opportunities for questions throughout the day and there were experienced operators and regulators in the audience to aid the discussions. Eadbhard Pernot of ZEP and Daniel Kitscha of DG CLIMA gave concluding remarks and thanked all for their contributions.

The day before ZEP and Bellona took advance of the international experts being in Brussels to hold a smaller 3 hour workshop for civil society organisations (NGOs) on CO₂ Storage Risk Management. IEAGHG was pleased to present in that workshop also, with great engagement by the attendees.

A very productive two days in the administrative centre of Europe, many thanks to ZEP!