CO₂ Storage: Site selection and Development

Choosing a CO₂ storage site starts with finding an industrial process that is a large source of CO₂ and can be fitted with capture technology or, in the case of power stations and facilities not yet built, deliberately locating them near suitable storage sites. Then, based on the amount of CO₂ that the facility is expected to produce over its lifetime, a search begins for a particular rock formation large enough to store the amount of expected CO₂ emissions.

Getting the storage site right in the planning stage is essential. If this is done effectively and the storage formation is deeply understood then potential risks can identified up front and plans put in place. There are some basic and essential questions that must be answered in order for a potential storage site to be considered for full site characterization.

The preliminary screening process aims to ask and answer the following questions:

Only when these basic and essential answers have been ascertained will any storage site be considered for full site characterization.

Site characterization starts by making an extensive study of the geology and environment of any prospective storage formation and its surrounding area.

Using data available from previous geologic work, such as government surveys or oil and gas exploration, or alternatively undertaking new seismic surveys and drilling, the geoscientists and engineers are able to identify and develop an understanding of its characteristics; from the engineered systems, e.g. pre-existing, abandoned and/or potentially required new wells, to the natural systems, e.g. geological structures, faults, groundwater locations and rock chemistry. Then – just as in oil and gas production – the next step is to run computer simulations and model the behaviour of the CO₂in the proposed storage reservoir, following up with field tests to verify the simulations, as well as collecting baseline data for future monitoring.

After undertaking these studies, detailed engineering plans for the project are developed that set out how the facility will operate under normal conditions, what potential risks there may be that need to be mitigated, as well as the site-specific risk mitigation plan and monitoring regime. As with any engineered system – from buildings and dams to railways and roads – there is no such thing as absolutely zero risk. But with careful analysis and the extensive risk management experience gained through operating complex, large-scale engineering processes like gas injection and offshore drilling over many decades, risks can be effectively identified, managed and minimised such that storage security can be ensured.