Tyler Hamilton has an article at Technology Review on a new process using concentrated solar thermal power to convert biomass to biofuel - Gasifying Biomass with Sunlight.
Sundrop Fuels, a startup based in Louisville, CO, says it has developed a cleaner and more efficient way to turn biomass into synthetic fuels by harnessing the intense heat of the sun to vaporize wood and crop waste. Its process can produce twice the amount of gasoline or diesel per ton of biomass compared to conventional biomass gasification systems, the company claims.
Gasification occurs when dry biomass or other carbon-based materials are heated to above 700 ºC in the presence of steam. At those temperatures, most of the biomass is converted to a synthetic gas. This "syngas" is made up of hydrogen and carbon monoxide, which are the chemical building blocks for higher-value fuels such as methanol, ethanol, and gasoline.
But the heat required for this process usually comes from a portion of the biomass being gasified. "You end up burning 30 to 35 percent of the biomass," says Alan Weimer, a chemical engineering professor at the University of Colorado, Boulder.
A few years ago, Weimer and his research team began looking at ways of using concentrated solar heat to drive the gasification process. It worked so well that Weimer and Chris Perkins, the graduate student who came up with the idea, went on to cofound Copernican Energy to commercialize the approach. Copernican was acquired by Sundrop Fuels in 2008, and its solar-reactor technology is now at the heart of a 1.5-megawatt thermal solar gasification demonstration facility in Colorado.