Some scientists have proposed compressing carbon dioxide and sticking it in underground caves as a way to cut down on greenhouse gases. Joe David Jones wants to make baking soda out of it.

Jones, the founder and CEO of Skyonic, has come up with an industrial process called SkyMine that captures 90 percent of the carbon dioxide coming out of smoke stacks and mixes it with sodium hydroxide to make sodium bicarbonate, or baking soda. The energy required for the reaction to turn the chemicals into baking soda comes from the waste heat from the factory.

"It is cleaner than food-grade (baking soda)," he said.

The system also removes 97 percent of the heavy metals, as well as most of the sulfur and nitrogen compounds, Jones said.

Luminant, a utility formerly known as TXU, installed a pilot version of the system at its Big Brown Steam Electric Station in Fairfield, Texas, last year. Skyonic, meanwhile, hopes to install a system that will consume the greenhouse gas output of a large--500 megawatts or so--power plant around 2009. Skyonic is currently designing one of these large systems.

"It has been working pretty well. It does present a potential solution to emissions," said a representative for Luminant. "But right now there is still a lot of work to be done."

If the concept works on a grand scale, it could help change some of the pernicious economics and daunting engineering challenges surrounding carbon capture and sequestration.

Carbon capture likely will be required to curb global warming, according to many scientists and companies that are currently experimenting with ways to effectively bury or fix greenhouse gases as they come out of smokestacks. Coal accounted for 26 percent of energy consumed in 2004 worldwide, according to the U.S. Energy Information Agency, and will grow to 28 percent by 2030. Coal also accounted for 39 percent of carbon dioxide in 2004 (behind oil) but is expected to pass oil for the No. 1 spot in 2010.

What about replacing every incandescent bulb in America with compact fluorescents? The benefits are eradicated by the carbon dioxide emitted by two coal-fired plants over a year, according to Ed Mazria, founder of Architecture 2030, a nonprofit that encourages builders, suppliers, and architects to move toward making carbon-neutral buildings by 2030.

Unfortunately, a lot of the proposed solutions for sequestration involve large amounts of capital and risk. If you bury carbon dioxide underground, it could always leak out. Other ideas include pumping it into underground saline aquifers or porous rock formations.

Because it's a solid, storing baking soda is simply easier, and it allows greenhouse gas emitters to store a lot of carbon in one place. The stuff piles up: A 500-megawatt power plant will produce approximately 338,000 tons of carbon dioxide a year. Multiply that weight by 1.9 and you get the number of tons of baking soda that the plant will produce. Still, it can be sold, stored in containers, used for landfill or buried in abandoned mines.

"If you can use the waste heat, it strikes me as a potentially feasible approach," said Alex Farrell, an assistant professor in the energy and resources group at the University of California at Berkeley. "I'm not willing to throw any of the ideas out yet."

On top of that, the byproducts of the different reactions--chlorine, baking soda, hydrogen (a byproduct from making the sodium hydroxide that gets mixed with the carbon dioxide), and chlorine--can be sold to industrial users. In all likelihood, the chlorine and hydrogen will have a higher market value than the baking soda, but baking soda does have its buyers. It is often used as an industrial abrasive. Besides, baking soda today gets mined--an expensive process. Skyonic's byproduct would obviate the need to dig holes in the ground. Read