Extreme weather might be an early warning of climate change. Solutions are in demand. So, is underground storage of CO2 a sustainable solution?
The Kyoto protocol is ratified. Emission trading schemes are in place. Research on energy efficiency and renewable energy is boosted. But is it still too little, too late, and too slow? Many believe so. CO2 capture and storage is therefore a hot topic.
“While CO2 storage may not be a silver bullet, it might just be the best thing to do,” says Tore A. Torp, Statoil’s CO2 expert, and an authoritative voice within the international forums where climate change and harmful emissions are combated.
“Underground storage of CO2 could help Europe to meet future Kyoto emissions trading targets,” says Tore A. Torp. “Therefore, it should be included as one option that gives credit for CO2 emission reduction under the Kyoto protocol.”
“This is not about shoving the dirt under the carpet, like some seem to think. Most of the CO2 comes from under the ground and putting it back there in a safe and secure way might actually be the most responsible thing we can do. The CO2 levels in the atmosphere are growing so fast,” he says.
Pioneering project
Acknowledging the need to do something, Statoil has gained valuable experience through actions.
As the first oil company in the world, Statoil led the pioneering project Sleipner, which started in 1996. For the first time in history, excessive amounts of CO2 contained in natural gas from the offshore Sleipner field was stripped off and injected above the gas reservoirs into the Utsira sandstone formation for long time storage.
About 2,800 tons of carbon dioxide are separated daily from Sleipner West’s gas production and injected into the Utsira sandstone formation, rather than released to the air. Unlike before, the CO2 was now injected to the ground only for environmental reasons. Previous experiences from capturing CO2 and injecting it into oil and gas reservoirs to squeeze out more oil and gas was helpful, but injection solely for environmental reasons was completely new.
Kept in place until the next ice age
In 2000 a research project demonstrated that the injected gas remains in place rather than leaking out. With a thickness of 250 metres, the Utsira formation can store 600 billion tonnes of CO2.
“The entire CO2 emissions from all the power stations in Europe the next 600 years could be deposited in this structure, and there are several such underground structures around the globe,” says Tore A. Torp.
One question asked by both researchers and other people when they hear about the Sleipner solution is how long the CO2 will remain underground.
Extensive inter-European research cooperation has been carried out on this project to study the CO2 underground behaviour and the probability of leaks.
Tore A. Torp admits that the researchers cannot promise it will stay in store for ever. “But a duration until the next ice age, in 5–10,000 years, must be good enough,” he says.
Technology development to cut costs
Referring to recent studies, Tore A. Torp estimates the cost of installing the best available CO2 capture technology at a gas fired power station, piping it out in the North Sea and re-injecting the CO2 under the seabed would cost 40 euro per tonne of CO2.
“However,” he says, “although the technology is currently expensive, the burden could be reduced to a manageable level by spreading the cost. As long as it’s free to emit CO2, anything else will cost more.” In Norway, where Statoil has 80 per cent of its production, a tax on CO2 emissions have effectively forced energy companies to find ways of reducing CO2 emissions. European countries have now started emission trading to the same end.
The work continues
Even though the technology is expensive, Statoil is going to store excessive amounts of CO2 (700,000 tonnes per year) from the new Snøhvit field once the gas is on stream. Such massive projects will also help bring about better and more affordable technology solutions.
Statoil is keen to pursue viable and sustainable methods that can help reduce CO2 emissions at a pace that really makes a difference. Through the EU and other international organisations, the research cooperation continues. All results about storage is open and being published.
“I am glad that DNV plays a role in this. Through its strong knowledge base and independence, DNV can contribute to create an understanding of both facts and the risks involved when dealing with CO2 emissions reduction,” says Tore A. Torp.