General Electric Oil and Gas has landed a $400 million deal with the developers of a large natural gas field in Australia that will help push carbon capture and sequestration from theory to reality.

As part of the Gorgon natural gas project, GE will provide the developers with six compression trains-complex pieces of industrial machinery and turbines for compressing gases that will inject carbon dioxide that bubbles out of the Gorgon wells into nearby Dupuy Formation 2.5 kilometers below the surface.

The compression trains will inject approximately 3.3 million tons of carbon dioxide a year under the seabed. That's the equivalent of taking 630,000 cars off U.S. roads. Typically, natural gas developers just vent the carbon dioxide extracted from wells into the atmosphere.

Gorgon is expected to produce 15 million tons of liquefied natural gas a year. Most of it will get shipped to China, South Korea, India, Japan and Australia. In all, it will produce 40 trillion cubic feet of gas over a 40 year period, says GE's Nigel O'Connor, or enough to supply Dublin with natural gas for 800 years.

The project is located on Barrow Island, a nature reserve approximately 130 kilometers off the coast of Western Australia where oil operations have also been conducted for over 40 years. Chevron owns 50 percent of the project while ExxonMobil and Shell own 25 percent each.

The project, no doubt, will also be monitored for safety, leakage, seismic activity and other parameters. Scientists and policy makers have pointed out the need for developing carbon capture and sequestration techniques for years. The capture part is easy-the difficulty lay in economical sequestration. The UN Intergovernmental Panel on Global Change (IPCC) estimates that 10 percent to 50 percent of the emissions reductions goals for 2100 could come from CCS. Humans emit about 27 gigatons of CO2 every year.

One of the biggest sequestration projects to date, the Scwarze Pumpe in Germany, is designed to capture 100,000 tons of carbon dioxide and will be expanded if it succeeds. Although technically ready to go, local opponents have prevented Vattenfall from getting all of the necessary permits. Other companies such as Skyonic, Carbon Sciences, PARC and Calera have proposed turning carbon dioxide into commercially interesting minerals or fuel, but many are skeptical whether transformation will work economically or can capture the massive doses of carbon dioxide that humans emit.

How does Gorgon work? In a nutshell, gas is extracted from the earth,  stripped of any lingering carbon dioxide, and the remaining methane gets refrigerated to minus 160 degrees Celsius to turn it into a liquid for shipping. When it arrives at its destination, the liquid gets transformed back into a gas for pipeline distribution. (Gas-to-liquid or GTL, by contrast, involves chemically transforming methane into a liquid fuel for cars that remains a liquid at normal temperatures.)

GE will produce three refrigerated compression trains for condensing methane into a liquid and six compression trains for injecting the carbon dioxide. The equipment will be made in Italy and shipped in 2011 and 2012.

The sequestration project, of course, won't have any effect on the greenhouse gases produced after the methane gets burned. Methane, though, is cleaner than coal, generating about half of the greenhouse gases, and less expensive at the moment than alternative sources of energy. Gas is also highly efficient when burned directly for cooking or heating. Overall, Gorgon will curb an estimated 45 million tons of greenhouse gases annually when coal abatement is added.

The Energy Information Administration estimates that demand for natural gas will grow by 67 percent by 2030 from today.

Tags: carbon capture, carbon dioxide, chevron, exxonmobil, general electric, sequestration, shell, underground storage, vattenfall