Green tea: Joule Energy’s SolarConverter turns carbon dioxide and sunlight into ethanol fuel at a pilot plant in Leander, Texas.
Joule Unlimited, a startup based in Bedford, Massachusetts, has received $70 million to commercialize technology that uses microörganisms to turn sunlight and carbon dioxide into liquid fuel.
The company claims that its genetically engineered bacteria will eventually be able to produce ethanol for as little as $1.23 a gallon or diesel fuel for $1.19 a gallon, less than half the current cost of both fossil fuels and existing biofuels.
The new funding comes from undisclosed investors and will allow the company to expand from an existing pilot plant to its first small-scale production facility, in Hobbs, New Mexico.
Joule Unlimited has designed a device it calls the SolarConverter, in which thin, clear panels circulate brackish water and a nitrogen-based growth medium bubbling with carbon dioxide. Inside the converter, the engineered microörganisms use energy from the sun to convert the water and gas into ethanol or paraffinic hydrocarbons, the primary component of diesel fuel.
Enclosed solar conversion systems are expensive and difficult to manage. But Joule Unlimited’s technology could prove practical because its microbes produce fuel continuously and efficiently.
The company, formerly known as Joule Biotechnologies, claimed in 2009 that its organisms could in theory produce as much as 20,000 gallons of ethanol on an acre of land in single year. Company officials now say their target is 25,000 gallons per acre, and that efficiencies they have already demonstrated take them 60 percent of the way to that goal.
The achievement would put Joule’s fuel ahead of cellulosic ethanol in terms of productivity. “Even at 60 percent of our ultimate goal, our productivity is still leaps and bounds above cellulosic ethanol,” says Dan Robertson, Joule Unlimited’s senior vice president of biological sciences. Cellulosic fuels such as grass and wood chips yield only 2,000 to 3,000 gallons of ethanol per acre per year, Robertson says.