Ceres, Choren assess energy crops for thermochemical biofuels production

Posted November 24, 2009, at 7:13 a.m. CST

Energy crop company Ceres Inc. announced Nov. 24 that it is working with Choren, an international leader in biomass-to-liquids (BTL) technology, to optimize energy crops for thermochemical conversion to advanced low-carbon biofuels. The two-year bioenergy project is funded in part by a grant from the U.S. DOE.

The thermochemical process does not require enzymes or microorganisms; instead, the biomass is gasified under certain heat and pressure conditions producing synthesis gas, a carbon monoxide and hydrogen-rich gas that can be converted into high quality synthetic fuels, intermediate chemicals or electricity.

In its role, Ceres will evaluate the composition of a broad range of switchgrass and willow plants, and provide biomass samples to Choren for thermochemical processing. The results will be used to identify the most relevant compositional traits, and later, to select the plants and traits that improve conversion and maximize fuel yields.

Chemical composition of grasses and woody crops varies considerably, even among different seed varieties of the same species. Through selective plant breeding and modern biology, therefore, the composition of energy crops can be optimized for greater thermochemical and economic efficiency. For instance, switchgrass biomass with lower amounts of sulfur or ash would be considerably less costly to convert into fuel.

"Our goal here is to develop energy crop varieties specifically tailored to thermochemical processing," said Anna Rath, Ceres vice president of commercial development. "As with other conversion processes, improvements to the biomass itself - through higher tons per acre and higher convertibility - can have a tremendous impact on reducing costs." Raw materials, or feedstocks, could represent up to 50 percent of the cost of producing transportation fuels.

"Fine-tuning feedstocks will contribute greatly to process economics, enhancing the quality of the synthesis gas mixture and reducing the capital costs associated with the downstream gas-cleaning operations," said Christopher Peters, vice president of finance at Choren USA. "This type of lock-and-key approach between feedstocks and processing technology will be critical in the commercial scale-up of the advanced renewable fuel industry." He noted that results of the study will assist Choren in determining the location of its first commercial-scale BTL facility in the United States.

In addition, Ceres and Choren plan to test commercial quantities of dedicated energy crops in a future collaboration effort at the world's first commercially operating BTL facility in Freiberg, Germany. "The operational experience gained in this commercial setting will provide invaluable and unique information to guide crop development," said Rath.

Switchgrass and willow are attractive dedicated energy crops because high biomass yields can be obtained with minimal inputs. These crops can also grow on lands that are less suitable for food crop production. Perennial grasses and woody crops have been shown to reduce greenhouse gas emissions.