Several hundred farmers braved cold, wind and rain this week at Emmetsburg, Iowa, USA, to see the latest in pre-commercial equipment designed for harvesting corn cobs for cellulosic ethanol production.

The event was the POET Project Liberty field day.

Project Liberty is POET's effort to commercialise cellulosic ethanol.

The project will be a 25 million-gallon-per year cellulosic ethanol plant located within the current grain ethanol plant.

POET's pilot-scale plant in Scotland, South Dakota, is already producing cellulosic ethanol at a rate of approximately 20,000 gallons per year.

"We feel this can be a brand new revenue stream for farmers," said Jeff Broin, POET chief executive.

"It's a tremendous opportunity for farmers and rural America.

"We had 800 farmers here last year and the equipment continues to improve."

Corn cobs are the feedstock of choice for POET.

But collecting corn cobs can be a challenge while trying to get the harvest done on time.

That's why a number of companies have been working with POET, farmers and others for several years to develop commercially viable equipment for collecting, storing and transporting corn cobs to the plant.

Sixteen companies demonstrated a wide variety of such equipment at Emmetsburg - everything from attachments to the back of the combine to tow behind units that collect and dump or feed into a dump cart.

Here's an example of some of the equipment demonstrated:

• AGCO demonstrated a one-pass system that marries the combine to a Hesston large square baler to collect and package clean stover, corn cob and leaf mixture into a 3-foot by 4-foot square bale.
• Case IH showed off their "extremely prototype" biomass cart. It's designed to collect grain and cob which would then be run through a separator.
• John Deere's unit on the back of the combine is "one pass, two stream machine," according to Dean Acheson. "You can collect only cob or collect more residue with it," he explains.