Northern Illinois University

NIU Office of Public Affairs

Peter Schubert
Dr. Peter Schubert,
Packer Engineering

To obtain a print-quality JPEG of this photo, contact the Office of Public Affairs at (815) 753-1681 or e-mail

News Release

Contact: Joe King, NIU Office of Public Affairs
(815) 753-4299

July 8, 2008

Power plant harvests electricity from farm fields

Naperville, Ill. — One of the keys to energy independence for farmers is left rotting in the fields every fall, believes Dr. Peter Schubert, senior director of research at Packer Engineering, Inc.

The corn stalks and other agricultural waste, which are ground up and left to decompose on the fields, could instead be used to fire up farm-scale generators to provide more than meet the electricity needs of the average farm, he says. A farmer with 600 acres of corn would have enough fuel to meet all of his power needs for a year, with plenty left over to sell back to the electric utility.

That power plant, the Stalk Stoker, as Schubert calls it, currently resides on his drawing board; but the technologies that it will employ are all tested and reliable.

“Our design simply extends proven technology,” Schubert explains. “By employing higher temperatures, and working in an oxygen starved environment, we can achieve the efficiencies to make this feasible on a farm-sized scale.”

Schubert, an electrical engineer, is senior director of research and development for Naperville-based Packer Engineering, a multi-disciplinary engineering consulting and technical services company that offers services across every engineering discipline. Schubert holds more than 25 patents, and has been principal investigator on research projects for NASA, the Department of Energy and the U.S. Department of Agriculture. His work has ranged from designing electronic controls for cars to developing artificial intelligence optimization techniques to increase engineering productivity.

His true passion, however, lies in developing sustainable energy solutions that do not pollute the environment. The Stalk Stoker, he says, fits that profile.

As he envisions it, each fall, rather than scattering stalk waste across the fields, farmers would instead use their existing balers to gather up the stalks into round bales (leaving behind 20 percent of the organic matter to replenish the soil.)

The stalk material would then be run through a grinder or hammer mill and fed into an oven-like compartment in the machine. That oven, which operates in an oxygen depleted environment, would be heated to about 1,000 degrees Celsius, at which point the organic material breaks down into combustible gases that are captured and then ignited to power a micro-turbine (a device similar to a jet engine) which in turn cranks a generator that produces electricity. The gas also can be compressed and stored for later use.

The process creates only two byproducts: heat and ash.

The heat can be captured and harnessed in two ways. Heat released in the breakdown of the plant material is returned to the process to keep temperatures high and improve efficiencies. (The device has an efficiency rating of about 60 percent. By comparison a gasoline engine has an efficiency rating of 25 percent.) The heat vented from the micro-turbine can be harnessed for any number of uses – from heating barns to making hot water or drying the grain harvest inside silos.

As for the ash, it is comprised mostly of minerals like potassium and phosphorus, nutrients which can be returned to the soil, helping to reduce fertilizer bills.

The device can help significantly cut fertilizer bills in another way.

The USDA recently gave Schubert and Savanna-based N-Ovations a $1 million research and development grant to marry the Stalk Stoker with a device created by N-Ovations, which uses artificial lightning to pull nitrogen from the air to make fertilizer. The process, based upon proven, century-old technology allows for the creation of nitrogen fertilizers without the use of natural gas. Skyrocketing natural gas prices are one of the primary causes for escalating fertilizer prices which jumped by 65 percent in the past year.

Schubert was introduced to the N-Ovations team by representatives from Northern Illinois University who were working with each on separate projects and realized the potential benefits of merging the two. NIU was instrumental in helping to secure the USDA grant and continues to provide engineering research, testing and support to both.

The fertilizer apparatus requires significant amounts of electricity, but the Stalk Stoker should generate enough power to not only operate that device, but also meet the other power needs of the farm. In fact, says Schubert, efficiencies should be high enough that farmers could actually sell power back to the grid. In states where power companies are required to pay prevailing commercial rates for such power, the machine would pay for itself in a year, Schubert says. In states like Illinois, where power companies pay reduced rates for such power the pay back would be slower, but savings realized by unplugging from the grid would cover the cost in about three years, he says.

Harnessing the heat from the exhaust to dry grain and do other chores would create more savings by reducing the amount of money farmers spend on natural gas or propane. It would also reduce the “carbon footprint” of their operations.

“This process is carbon neutral,” explains Schubert. “It uses no fossil fuels, and the only carbon it puts into the atmosphere comes from the plant material it consumes – and that carbon would be released anyway as the stalks break down. We are just accelerating that process.”

Schubert and a team at Packer are in the final design phase of the project and hope to have a prototype operational in a matter of months.

Schubert is anxious to get the machine fired up, because he sees many far reaching benefits and not just for farmers. His hope is that the Stalk Stoker can be built in Illinois to help stimulate the manufacturing economy. Furthermore, he says, its uses are not limited to farms. In rural areas around the world it could be harnessed to power and heat schools, hospitals, small factories or homes – all while reducing the use of fossil fuels.

“It’s good for the region, good for America and good for the planet,” he says.

# # #