New report is shedding light on evidence and use cases suggesting unforeseen risks are associated with carbon capture and storage (CCS) projects which questions their viability in the long run. The report is issued on June 14th from the Institute for Energy Economics and Financial Analysis (IEEFA) and examines two flagship CCS projects – Sleipner and Snøhvit.
It is titled: Norway’s Sleipner and Snøhvit CCS: Industry models or cautionary tales? and is authored by Grant Hauber, IEEFA’s Strategic Energy Finance Advisor. The two flagship projects have been looked as success stories and examples of underground storage of industrial CO2. However, due to unexpected subsurface challenges, these carbon capture and storage large-scale initiatives have been facing underground unknowns which spurred financial and environmental risks.
The report concludes that rather than being models for CCS, the two projects raise a cautionary tale about the technical and financial viability of the concept in the long run.
The Sleipner and Snøhvit CCS projects are developed by the Norwegian energy major Equinor. Both of them faced unexpected geologic challenges over the years. Every project site has unique geology, additionally, subsurface conditions are changing. They exist at a given point on the Earth and any information obtained about a place is only a snapshot in time. As the Earth moves, strata can change.
At Sleipner, over the course of only three years of operations, stored CO2 quickly migrated upward 220m, in the process exposing the presence of a previously unknown geological stratum in 1999. CO2 migration rates to this new stratum accelerated over time. Fortunately, this zone appears covered by solid caprock, keeping the CO2 trapped for now. However, as CO2 injections continue, scientists do not know how far that containment extends, raising questions for the future.
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At Snøhvit, pressure in the CO2 deposit area rose rapidly to alarming levels in 2010, just a year and a half after injections began, as the targeted storage rock was not accepting CO2 at anywhere near the rate design studies indicated. Storage estimates dropped from 18 years to only six months, triggering an emergency well intervention to find a temporary solution.
The unexpected event forced Equinor to look for new CO2 storage areas, and in 2016, it invested in another injection site as part of a $225 million capital expenditure campaign to improve production and storage operations.
“Snøhvit highlights the need for CCS projects to have continuous monitoring, extensive backup plans and the money to implement them. Sleipner proves that injected CO2 can start behaving in unexpected ways despite what appears to have been years of nominal performance,” explained Hauber.
Such unforeseen circumstances cast doubt on whether the world has sufficient technical ability, strength of regulatory oversight, and unwavering multi-decade commitment of capital and resources needed to monitor and keep the CO2 sequestered underground.
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The report also says that there are more than 200 CCS proposals under consideration worldwide. Sleipner and Snøhvit have been showcased as proof in the proposals of those projects that large-scale offshore CO2 storage is a viable means to help mitigate CO2 emissions.
However, those proposed CCS projects have a storage capacity exceeding 10 times those of Sleipner and Snøhvit. The report indicates that there is no way that they can be proxies for other CCS projects of such large scale.
“Subsurface CO2 storage is an amalgamation of probabilities and risks, some of which can be identified, others remaining unknown until troubles materialize. These risks – and the costs that accompany them – are not being made part of public discourse by either industry or government,” states the report.
