Poet Cellulosic Plant To Be Partially Powered by Waste Material

A self-sustaining energy cycle for producing cellulosic ethanol is close to reality, Poet said, with the recent startup of an anaerobic digester at the company’s pilot plant in Scotland, S.D.

Corn cobs at Poet’s commercial-scale plant, to be called Project Liberty, will not only be used to produce ethanol; the liquid waste will go to an anaerobic digester to power the cellulosic plant and offset natural gas usage at the attached grain ethanol plant as well. As a result, renewable energy created at the plant will be powering the plant and the adjacent facility.

Poet installed and fired up its anaerobic digester, which was designed and built by Biothane, on May 20. The digester uses liquid waste created in the process of converting corn cobs to ethanol. That waste is used to produce methane gas, which acts as roughly the equivalent of natural gas.

"This technology will cut fossil fuels out of our cellulosic ethanol production process and further improve the benefits of grain-based ethanol," Poet CEO Jeff Broin said. "Over the long term, Poet would like to eliminate the use of fossil fuels at all of our plants through a variety of alternative energy sources." The alternative energy technologies employed at other Poet facilities include a solid waste fuel boiler, landfill gas and cogeneration.

The digester is in the research phase–corn cobs have never been used in this way before, the company said in a statement. The methane is currently being flared (burned off), but once the process is refined, it will be installed as part of Project Liberty.

Project Liberty is a 25 million gallon-per-year cellulosic ethanol plant, which will be built in Emmetsburg, Iowa. Research and development work is on schedule for the plant to begin production in 2011, Poet said.

Poet is the largest ethanol producer in the world. The 20-year-old company produces more than 1.54 billion gallons of ethanol annually from 26 production facilities nationwide. Poet recently started up a pilot-scale cellulosic ethanol plant, which uses corn cobs as feedstock.