A troublesome greenhouse gas could be an energy source, say Dutch scientists describing a new method for producing electricity from carbon dioxide.

Reporting their work in the American Chemical Society's journal Environmental Science & Technology Letters, they describe technology that would have CO2 react with water or other liquids and, with further processing, produce a flow of electrons that produce electric current.

Electric power-generating stations worldwide release about 12 billion tons of CO2 annually from combustion of coal, oil and natural gas, while home and commercial heating produces another 11 billion tons, Bert Hamelers of the Wetsus Centre of Excellence for Sustainable Water Technology in the Netherlands said.

The new technology could produce about 1,570 kilowatts of additional electricity annually -- about 400 times the annual electrical output of the Hoover Dam -- if used to harvest CO2 from power plants, industry and residences, Hamelers and his colleagues said.

Using CO2 from electric power plants and other smokestacks as a raw material for making electricity could create additional supplies without adding more of the greenhouse gas to the atmosphere, Hamelers said.

The approach, he emphasized, does not get rid of the CO2.

"You use the energy that is now wasted. You bring it in and get the extra energy out, but you cannot sequester it," he said.