19 October 2022
To keep global warming temperatures below 1.5°C, many thousands of CO2 storage wells will be required by 2050 to lock away millions of tonnes of CO2 underground for thousands of years. This report outlines the latest evidence on the practicalities and challenges associated with storing CO2.
Geological Carbon Storage Policy Briefing
Once CO2 has been captured from point sources, such as industrial plants, or directly from the air, it can be compressed and injected into rocks at depths of 1 – 2.5km below the surface of the Earth, safely trapping it for thousands of years. These storage reservoirs are typically made up of a sandwich of permeable rock, with overlying and underlying layers of impermeable rock which prevent the CO2 from escaping.
The geology of each potential storage site is unique and thus it is required to characterise each site to determine:
As the site develops, different challenges related to monitoring, assurance and storage optimisation will arise and need to be overcome to maximise the efficiency of a site.
The chance of CO2 escaping the reservoir is low, and well-regulated wells are estimated to retain 98% of their CO2 over 10,000 years. Measures to ensure CO2 is injected safely include:
CCS is a required practise to achieve Net Zero. As the CO2 storage industry develops, there will be continued advances in improving predictions of CO2 migration, technologies for monitoring reservoirs, and enhancing the capacity of storage systems. All of these advances will increase the efficiency of CO2 storage and speed of setting up new CCS sites.
In addition, novel storage techniques are also emerging, including harnessing reactions between CO2 and minerals to store carbon, which could dramatically increase the number of places where CCS is geologically possible.
It is predicted that up to 400 new wells are required each year up to 2050 to achieve global climate ambitions. This will need to be underpinned by fundamental and continual research, and the emergence of an appropriate policy and regulatory environment to make CCS a safe and effective practise for a low-carbon future.