D5.3 Recommendations for safety and performance analyses of storage pilot in the Ebro Basin

1. Project Overview and Objectives

This report summarizes a detailed study on the safety of permanently storing carbon dioxide (CO₂) deep underground in the Lopín site, near the town of Quinto, in the Ebro Basin. CO₂ is a major gas contributing to climate change. The technology being investigated, called Carbon Capture and Storage (CCS), involves capturing CO₂ emissions from industry and injecting them into suitable deep rock formations, where they can be safely trapped for thousands of years.

This study is part of the European PilotSTRATEGY project, which is exploring the potential for this
technology in several regions, including the Lopín site in Spain.

2. The Geological Principles of Storage at Lopín

The safety of the Lopín site relies on geological principles that have been proven effective worldwide over millions of years. The site contains a multi-layered system where different rock types each play a crucial role:
i. An extensive, deeply isolated storage reservoir: A sandstone formation situated over 1,700 metres deep—far below the deepest freshwater aquifers used for human supply, creating a vast buffer zone that ensures complete isolation from surface ecosystems.
ii. An exceptionally robust, multi-barrier sealing system: The reservoir is capped by impermeable layers, primarily the Keuper Formation. This 400-metre-thick sequence of clays and evaporites represents a rock type known globally for its exceptional sealing capacity, as demonstrated by its natural ability to trap buoyant fluids like oil and gas over geological timescales.

3. Safety Assessment and Key Findings

A detailed risk analysis by experts has concluded that the pilot phase presents a very low-risk profile. This phase is designed to inject a limited volume of 100,000 tonnes of CO₂—a modest amount compared to the scale of natural geological formations, and a conservative threshold established by regulation specifically for research and demonstration purposes, ensuring a wide safety margin. The key findings are:
i. The CO₂ will stay where it is put: Computer models show that the CO₂ will not spread far enough to reach any nearby natural fractures or old wells.
ii. The natural seals are very strong: The layers of sealing rock are highly effective. Research shows that natural chemical reactions could even improve the sealing capability over time.
iii. No significant earthquake risk: For the pilot phase, the pressure created by injection is too low to cause any noticeable seismic activity.

In summary, for this pilot phase, the study concludes that the storage operation is safe and does not pose a significant risk to human health or the environment.

4. Considerations for Future Larger-Scale Storage

The study confirms that the geological features ensuring safety for the pilot project also provide a reliable foundation for potential larger-scale operations. Safety is an integral part of the system's design, achieved through continuous monitoring and proper pressure management—standard practices in geological storage worldwide. This proven approach ensures that any future expansion would maintain the same high safety standards established for the pilot phase.

5. Commitment to Safety and Regulatory Compliance

This project is conducted under strict European and Spanish regulations, which require proving complete safety before any permit is granted. The goal is to help fight climate change in a safe and reliable way, while maintaining open and transparent dialogue with citizens and local authorities. In short, this risk assessment uses scientific and technical evidence to demonstrate that the geological storage of CO₂ at the Lopín site can be conducted safely. This finding supports the use of this technology to manage unavoidable emissions from hard-to-abate industrial sectors, such as cement and chemical production, where few other alternatives exist. This makes it an essential component of a comprehensive climate strategy.