A range of evidence supports the role of carbon capture, usage and storage (CCUS) in delivering the most competitive and productive UK transition to a low carbon future.

The UK government has funded appraisal work on several of the many offshore saline aquifers potentially suitable for CO2 storage. As a result, our knowledge base relating to these stores is high, and some stores are ‘ready for business’.

Injecting CO2 into saline aquifers pressurises them, and since each store has a limiting pressure for integrity reasons, this can limit the storage capacity and CO2 injection rate, and so affect costs.

This paper, delivered by Energy Systems Catapult for the Energy Technologies Institute, describes the efficacy of a simple technique to alleviate this constraint – pressure is relieved by releasing the native water in the aquifer as it is filled with CO2. This is termed ‘brine production’.

This analysis reports the savings to the UK from deploying brine production in line with that needed to deliver lowest-cost decarbonisation pathways would be at least £2 billion, but would most likely be more.

Key points

• Investment risk mitigation and improved management of strategic investments – particularly in terms of being able to deploy brine production several years after initial store operation to mitigate the impact of unexpected conditions being experienced within the store geology, or in response to changing operational conditions.
• Technical risk mitigation – enabling a store to be operated (and decommissioned) at lower operating pressures than conventional injection approaches that don’t use brine production, thereby improving operational flexibility and reducing the risk of leakage from the stores.
• Skills development and wealth creation – although the brine production technology is physically relatively simple to implement, garnering the full benefit from its use will need skills, capabilities and expertise that the UK is well placed to develop from its offshore oil and gas industry, and offer as a service abroad.