By DUANE SCHRAG

Salina Journal

Sunflower Electric's plans for two coal-fired power plants in southwest Kansas initially call for a 500-acre algae bioreactor, the company said Thursday.

"Our initial preliminary financial model assumes a 500-acre reactor at a cost of $55 million," spokesman Steve Miller said. "Until we can do further testing (following issuance of the plant permit), we really can't comment beyond that."

Hays-based Sunflower already has a coal-powered plant in Holcomb, where it wants to build the two new plants -- a $3.6 billion project that the state has denied a permit for.

Sunflower, along with supporters of the proposed, 700 megawatt, power plants, have said the project would include a bioreactor that would capture 40 percent of the plant's carbon dioxide emissions from the new plants and use that to grow algae.

The algae then could be turned into ethanol, biodiesel, feedstocks or other value-added products.

It's not clear how much of the plants' carbon dioxide emissions -- it will generate about 2.8 million pounds of CO2 an hour -- a 500-acre bioreactor could process. Estimates range from as high as 4 percent to less than 1 percent.

GreenFuel Technologies, based in Cambridge, Mass., is helping design the bioreactor, according to Sunflower's Web site. Last year the company conducted a pilot project in Arizona that it described as "one of the most productive algal cultivation systems ever built."

During the pilot project, the average yield was 1 pound of algae a day for every 50 square feet. At that rate, a 500-acre reactor would capture about 1.2 percent of carbon dioxide emitted.

A study of the GreenFuel project by Australian scientist Krassen Dimitrov projects capture rates that are half that -- by his estimate, a 500-acre reactor would capture barely 0.5 percent of the carbon dioxide emitted. Dimitrov's science background includes research into optimizing biofuels.

But a company called Valcent Products (www.valcent.net) claims its algae reactor can far outperform GreenFuel's. According to its Web site, its reactor can capture "possibly as much as" 1,000 tons an acre per year. At that rate, a 500-acre reactor would capture 4.1 percent of the carbon dioxide.

It's not known how much such a reactor would cost.

Sunflower's plans assume a reactor that would cost about $2.50 a square foot. Dimitrov's estimate is $9.30 a square foot.