Wednesday, December 13, 2006

Carbon Dioxide Finds a Market in the North Sea

New technologies make concentrated CO2 for enhancing oil extraction. The problem: a lack of carbon dioxide.

By Peter Fairley

Sargas's high-pressure equipment is compact enough for use offshore; it supplies power and CO2 directly to aging oil fields. Credit: Sargas

Several oil giants, including BP, Shell and Norway's Statoil, recently announced plans to build new power plants designed to convert North Sea natural gas into hydrogen, burn the hydrogen to produce electricity, and ship the resulting carbon dioxide to offshore oil wells. BP expects to produce an extra 40 million barrels of oil as a result of its plant between 2010 when the plant starts and 2030.

Meanwhile, an Oslo-based startup, Sargas SA, has secured industrial backers to build a coal-fired power plant in Norway using a new technology called pressurized combustion that co-produces power and carbon dioxide; it plans to sell its CO2 to offshore drilling sites. Before that, Sargas hopes to begin building a smaller plant early in 2007 that could be the prototype for offshore platforms producing power and CO2 where they're needed most: out in the North Sea oil fields.

"There is a real economic driver for the use of the CO2 for enhance oil recovery," says MIT process design expert Gregory McRae, who is tracking developments in carbon capture. "Its an incredibly exciting time."

Using industrial CO₂ to enhance oil recovery could squeeze an extra 7.3 billion barrels of oil from the North Sea and simultaneously stow away 10 billion metric tons ofcarbon dioxide, according to a December 2005 study by the European Commission's Institute for Energy. The latter is the equivalent of stopping Europe's greenhouse gases releases for two and a half years.

What is holding up full development of the use of carbon dioxide for enhancing oil recovery is, ironically, a dearth of CO2. Dozens of natural gas and coal-fired power plants ringing the North Sea produce plenty, but capturing it is expensive because the CO2 in the flue gas is at very low pressure and concentration (most of the exhaust from a conventional planet is actually nitrogen gas carried through from the air used to fire the fuel). Carbon capture is estimated to add a 30 percent to 50 percent premium to the cost of producing electricity.

BP, Shell and Statoil's solution to the problem is a new plant design. Instead of just burning natural gas, the plants will use a chemical process called reforming to convert the fuel into concentrated streams of pure hydrogen and CO2. The hydrogen will be burned to produce electricity, while the CO2 would be pressurized and sent by pipeline to offshore oil platforms to be pumped into the hydrocarbon reservoirs below.