Repurposing old oil rigs to pump CO2 into rocks would actually be cheaper than decommissioning them

Carbon dioxide is a potent greenhouse gas and we are emitting it by a boat load. Of course, humanity has to find a way to cut emissions, but it is also important to clean the atmosphere we already have. CO2 capture and storage are very important technologies for the future. Now scientists from the University of Edinburgh conducted a study, which revealed that North Sea oil and gas rigs could be modified to pump vast quantities of carbon dioxide emissions into rocks below the seabed.

Oil rigs could be modified to pump CO2 to undersea rocks. Image credit: Erik Christensen via Wikimedia (CC BY-SA 3.0)

Scientists are trying to find a safe and effective way to rid atmosphere from carbon. CO2 could be injected into porous rocks, where it would dissolve and become a part of other materials. This would work, but this process itself would require a tremendous amount of energy, which would not necessarily be clean. Solution is to use old oil rigs and their existing wells. Even better – using the same equipment. Researchers found that repurposing old oil rigs to pump CO2 under the seabed would actually be 10 times cheaper than just decommissioning them.

Scientists analysed data from the Beatrice oilfield and found that only minor modifications would need to be made to convert oil rigs into CO2 pumping stations. Researchers used computer models to find that over 30 years of post-oil use as a CO2 storage pump, the price of modification would be way smaller than of decommissioning. Oil rigs generate a lot of money while they are working, but closing them is very expensive. In case of Beatrice oilfield the price of decommissioning could be more than £260 million. However, modified oil rigs would have to generate their own electricity to conduct CO2 storage operations.

This study showed that natural gas and heat energy can still be extracted from saltwater in exhausted oil and gas fields. This energy can be used to inject CO2 deep underground for permanent safe storage. Dr Stuart Gilfillan, one of the authors of the study, said: “Our study shows, for the first time, that natural gas production from saltwater can be combined with CO2 storage in the North Sea. The potential revenue provided by extending natural gas production in the North Sea could help kick-start a world-leading carbon capture and storage industry in the UK”.

Getting rid of CO2 is a major goal for humanity. Reducing atmospheric CO2 would help controlling the climate change. Of course, carbon storage is not a solution for our emissions, but it would definitely help. Especially since there are many decommissioned oil rigs – repurposing them would be cheaper and more useful.


Source: University of Edinburgh


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