Australia's first large underground carbon storage facility has opened in the southern state of Victoria. The geo-sequestration plant will capture carbon dioxide from a power station and store it two kilometers beneath the surface. Researchers think the pilot program will help Australia make deep cuts to its greenhouse gas emissions. But as Phil Mercer reports from Sydney, environmentalists are not convinced the technology is appropriate.

Australia's new carbon tomb lies near the town of Warrnambool, west of Melbourne. It is the first of its type in the Southern hemisphere. Under this type of geo-sequestration, carbon dioxide from power plants is compressed into liquid and pumped underground.

Several years of testing have convinced scientists that the facility in southern Australia will be able to safely absorb 100,000 tons of greenhouse gases.

Rock formations have been described as giant sponges that will soak up the carbon dioxide. The hope is that the dense fluid will remain locked away indefinitely.

Professor Victor Rudolph, a chemical engineer at the University of Queensland, says the technology should be an effective way to curb carbon dioxide emissions.

"You've got to, A: capture the CO2 [carbon dioxide], so you've got to get a hold of it first of all, then you compress it effectively into liquid form and you pump it down into the ground somewhere where it's securely kept for a long time," he said. "So, you've got to either find a cave or a space and something that seals it within that space then it just stays there forever."

Gases such as carbon dioxide, which are produced by burning fuels such as coal, oil and wood, are thought to contribute to global warming. Governments around the world are trying to reduce emissions of such gases by developing new green technologies.

Some critics, however, say though that this process is expensive, and there are concerns too that leaks from underground facilities could have harmful consequences in the future.

One of the project's chief architects, Peter Cook, says the technology will be carefully scrutinized.

"What we'll have is probably the most comprehensive monitoring program for stored carbon dioxide anywhere in the world. It will also be one of the largest pilot projects in the world," he said. "It's a very, very significant project even by world standards and we're having a number of international groups who'll be working with us as part of this experiment. So, it will be the first real test of geo-sequestration under Australian conditions."

The program has the support of the Australian government and the country's powerful coal industry.

Geo-sequestration technology is also being developed elsewhere, including in Japan and the United States.

Some environmental groups think that geo-sequestration has too many unknowns. Some have argued that the money spent on the Victorian project should have been allocated to proven technologies, such as solar and wind power.