Minnesota greenhouse using own biomass for energy savings

Pork & Plants, a farm and greenhouse business in southeastern Minnesota, is using its agricultural waste to heat its facilities. The farm won an innovation award for creating renewable biomass pellets that heat the greenhouses.

Pork & Plants is mainly a plant business today. The greenhouses rise up out of the Whitewater River Valley and cover a little over an acre of land. Eric Kreidermacher and his family own the business.

"We are well over 800, almost to 1,000, different varieties of things that we grow," Kreidermacher said. "Anything from geraniums to Mexican heather to Heliotrope, Trechilium; that's one most people aren't familiar with."

The farm started as a hog farm, but the plants took over. The greenhouses run year round, but heating a greenhouse in February isn't cheap.

"If we were still on LP gas like we were years ago, we'd burn 80,000 to 100,000 gallons a year," Kreidermacher said. "So, you do the math and it's psychotic."

That would cost the farm $155,000 per year. Kreidermacher said they'd be out of business with those rates.

So about five years ago, he started burning corn in his boiler. But the price per bushel peaked at $7, and then dropped to $3. Kreidermacher decided to look for another solution.

He and his brother figured out how to make biomass pellets from materials that came off the farm. These pellets could be used in the boilers in place of the traditional fuel.

"In spring of '09 we were 100 percent on the pellets, which for the most part consisted of corn stalks [and] bean straw," Kreidermacher said.

He said the switch cut their heating bills in half. Outside the boiler, shed bales of hay stand in lines like semi-trailers.

"So this is the pre-grinding stage; we grind everything here and then it goes in the room we were just in with the hammer mill to do the final grinding," Kreidermacher said.

After grinding, the material is mixed, cooked and spit out in pellet form. They burn without much ash and a produce a lot of energy.

Kreidermacher said finances were only part of his motivation for this project. He wanted to create a sustainable, closed-loop energy system. Even the hog manure goes on the crop land that then serves to heat the buildings.

"As a whole we have to go down this alternative road if we're going to be energy independent as a country," he said. "But people have to have the willpower. It's not an easy road, either. A lot of it is uncharted territory."

The latest frontier is the prairie. For the past three years, he has fostered prairies specifically to harvest the grasses in the fall, and then use the biomass for fuel. Nobody he knows has done that before, so he's tinkering with what flowers and grasses have the highest yield.

"I believe in the straight grass stuff we were two to two-and-a-half tons to the acre," he said. "I'd prefer to be four to eight. You know it needs to be, honestly."

Kreidermacher worked with the Agricultural Utilization Research Institute in Waseca. It's a nonprofit that helps businesses develop agricultural innovations. The group awarded Pork & Plants for its pellet innovation. They say part of the success of the pellets lies in the size of the operation. It's small enough to use only nearby materials.

Neighbors have asked the Kreidermachers if they might be able to pay to have their own pellets produced, and Pork & Plants now sell their pellets to other farmers and greenhouses.

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