Brush lands in the upper Midwest are a great biomass resource, but can be hard to harvest because the vegetation is thicker than most agricultural machinery allow, but not thick enough to warrant forestry equipment. Stempower Resources' Biobaler is designed to aggregate vegetation 1 to 8 inches in diameter and can link land management with the biomass supply chain.

The cutting and baling equipment simultaneously harvests and bales brush with minimal soil disturbance. It's been on the market for about four months and Stempower, based in St. Joseph, Minn., has focused on linking its capabilities with the land management industry, according to Peter Gillitzer, Stempower president and co-founder. The coupling can offer lower management costs, and therefore a savings to wildlife management agencies that clear land to create habitats. The Biobaler can also bring in extra revenue if buyers for the bales can be secured, which Gillitzer said has been the biggest challenge.

Minnesota Power recently tested about 12 truckloads of the bales in its ML Hibbard steam electric generating plant in Duluth. The company is evaluating the bales' fuel quality, availability, Btu value and moisture content to determine whether they are viable as a long-term feedstock. "They've burned all the loads but are still working on the analytics," Gillitzer said, adding that further discussions and negotiations are ongoing. Minnesota Power most likely would not operate its own Biobaler, but would purchase bales already harvested. "They're really good at running plants and don't have any interest in operating one of these," he said. Stempower is also in discussions with other power generators for the purchase or testing of bales, but Gillitzer declined to release more information, as no contracts are in place.

Brush is an attractive biomass resource because there is no competition for a supply from paper mills, it can be stored indefinitely without rotting, and dries naturally in the sun without expensive equipment, Gillitzer said.