WASHINGTON: Can global warming be curbed by soda pop?

Far-fetched as it may sound, scientists and industry leaders are working on technologies to capture power plant carbon dioxide emissions linked to global warming, and use them for commercial purposes.

Commercially-marketed carbon dioxide is used for oil and gas exploration, fire extinguishers, dry ice and carbonated soft drinks like Pepsi and Coca-Cola.

Separating and removing carbon dioxide from power plant emissions would eliminate a major source of greenhouse gases from the atmosphere. Making the gas available commercially would be an added benefit, say researchers.

Carbon dioxide that could not be sold commercially would be "sequestered" or buried in ground formations or in the ocean.

The US Department of Energy is spending US$19 million on research on carbon "capturing" and sequestration.

One of these projects being built by California-based Clean Energy Systems Inc is a smokestack-free power generator that captures 100 per cent of carbon dioxide emissions and makes it available for industry.

By making the carbon dioxide commercially available, "you're reducing the amount of carbon dioxide you have to manufacture," explained company Vice-President Ronald Bischoff.

When carbon dioxide is used in food or beverages, it may eventually return to the atmosphere, Bischoff said. But when it is injected in the ground for storage or recovery, "it doesn't come back."

The company is working on commercial power generation in areas where carbon emissions are capped. It is also building a 10 megawatt, US$70 million zero-emission facility at the government's Lawrence Livermore National Laboratory that would remove carbon dioxide from the process.

The carbon dioxide could be "sold as a commodity to soda pop and dry ice manufacturers, as well as to the petroleum industry to enhance oil and gas recovery," according to a statement from the laboratory.

Otherwise, according to Livermore officials, carbon dioxide could be deposited into the ground for about US$20 per ton, less than the cost of removing the gas from the exhausts of existing electric plants.

Outside the United States, scientists in Japan are working on a method that pumps carbon dioxide to the sea floor, where it spreads out as a liquid. Meanwhile European researchers are injecting CO2 into a deep saline aquifer off the North Sea.

"This is one of the most promising technologies right now," said Amy Veawab, a Canadian researcher at the University of Regina. "It would be more economical if we can re-use it (carbon dioxide) for industry."

A recent World Bank report concluded that "CO2 capture and sequestration is receiving increased interest as a potential solution to climate change" and that a number of studies have been launched worldwide in this area.

The World Bank report notes that some power facilities already use CO2 for food processing, freezing and chilling, as well as beverage production.

"CO2 separation costs from these facilities are estimated to be approximately US$100 per ton," it said. "This compares favourably to refined CO2, which sells for US$50 to US$300 per ton."

But environmentalists are sceptical about this as a solution to global warming and claim the environmental impact of dumping carbon dioxide in the ocean or underground has not been adequately studied.

"We think there should be an ecological risk assessment, no one knows how long the carbon will stay down there," says Susanne Moser of the Union of Concerned Scientists, which favours reduced use of fossil fuels to curb global warming.

"They are years or generations away" from a practical solution, says Michael Oppenheimer, chief scientist at the Environmental Defense Fund. He contends that use of renewable energy sources such as wind or solar power could have a more immediate help for global warming.

As for recapturing carbon dioxide for commercial uses, Oppenheimer says, "there's not enough of a market ... you can just make so much soda."

Agencies via Xinhua