Now it’s sent back to where it came from – far below the earth’s surface – and that’s helping turn the desert, or at least Algeria’s gas exports to Europe, green.
Our carbon capture and storage (CCS) plant at In Salah’s Krechba gas production site re-injects up to 1.2 million tonnes of CO2 each year into a geological formation some two kilometres below the surface. That’s equivalent to taking about 250,000 cars off the road.
Sigbjørn Ohnstad
“We’ll store it indefinitely, or at least up to 1000 years, as recommended by the United Nations,” says operations manager Sigbjørn Ohnstad of the In Salah gas joint venture.
It’s a lot like Sleipner, StatoilHydro’s gas production and CO2 capture and storage platform in the North Sea. Sleipner strips carbon dioxide from the gas well stream before re-injecting and storing it in the Utsira formation some 1000 metres below the sea’s surface.
In 2004, a joint industry programme was started between Algerian national oil company Sonatrach, BP, StatoilHydro, and several R&D groups in Europe and the USA. The goal is to verify long-term storage of CO2 at Krechba and demonstrate industrial-scale geological storage as a viable option.
“It is the first time CO2 is being stored on an industrial scale in a gas reservoir that is simultaneously being produced,” explains In Salah gas joint venture subsurface manager Pål Ingsøy. “The geologists are confident that the quality of the seal, some 900 metres of shale, is solid. The only drawback is it’s harder to predict the movement of the CO2.”
Consequently, a CO2 monitoring program is in place and reservoir modelling and simulation are actively carried out.
“The experience we get here can help unlock significant potential for future CO2 storage,” says Mr Ingsøy.
The In Salah field accounts for about 12% of Algeria’s total gas output and is expected to produce gas for at least another decade. Algeria is the third-largest supplier of gas to Europe. It presently exports some 63 bcm per year through pipelines to Spain and Italy. Export volumes could reach as high as 85 bcm per year by 2010. A large percentage of the exported gas is LNG.
In Salah's natural gas holds 5 to 6 percent carbon dioxide but its main customer, the European Union, only accepts 2 percent. The Krechba CCS plant purifies In Salah’s gas to a 0.3 percent carbon level.
StatoilHydro sees CCS projects as a potential source of profit if environmental rules change. Carbon sequestration on gas fields isn’t currently taken into account by the Kyoto Protocol, which regulates emissions of greenhouse gases and arbitrates how companies can obtain carbon credits for limiting pollution.
“This could change as global leaders and the UN negotiate a new treaty to succeed Kyoto, which expires in 2012,” says StatoilHydro’s head of government and public affairs in Algeria, Per Henning Hanssen.
“Credits for saved carbon could generate millions of dollars of additional income to gas production sites like In Salah, and make CCS economically viable for other projects,” he adds.
