Gasification turns biomass into mini-powerplant fuel

A demonstration project conducted by the Energy and Environmental Research Center at the University of North Dakota may turn two nagging environmental challenges, diesel engines and woody waste, into renewable energy solutions.

The EERC is operating a gas production unit and firing a diesel engine generator from forest residues, wood chips, sawdust and agricultural by-products. Biomass gasification technology was used to extract the fuel, similar to natural gas, from wood waste.

Research Manager Darren Schmidt said, “We believe that the project has good economic potential.”

Remote power source disposes of waste material
The concept is based on the National Renewable Energy Laboratory’s Small Modular Biomass Initiative. The program’s goal is to develop biomass-powered generators of 5 kW to 5 MW that are flexible, efficient and simple to install and operate. Ideal for powering remote villages, farms and ranches, the systems can also serve a dual purpose for industries that produce biomass waste and consume large quantities of electric power.

SMB initiative partners and project sponsors include the U.S. Department of Energy; the California Energy Commission; FlexEnergy; the North Dakota Department of Commerce Division of Community Services; Primeboard, Inc.; and the Massachusetts Technology Collaborative.

EERC became involved in the demonstration when FlexEnergy contracted with the research center to provide a biomass gasification system to fuel its Capstone Flex-Microturbine. FlexEnergy developed the unit to run on very low-heat value, low-pressure gas. “As part of the product development, they wanted to test it on gasifier-produced fuel,” explained Schmidt, “and EERC has a lot of experience with that technology.”

Modifications adapt system to U.S. business needs
A company in India supplied the gasifier used in the demonstration. “In India, the technology has already crossed the hurdle to commercialization,” said Schmidt, “but the environmental, safety and economic standards are different in the U.S. You can’t just plug the unit in.”

EERC modified the gasifier to run on wood pellets instead of wood chunks, and automated the system so it did not require a large staff to operate it. “It was semi-automated, but it needed some upgrades to make it cost-effective for American industry,” Schmidt noted.

Integrating the gasifier onto a 45-foot trailer for portability was a critical modification, the research manager added. “Since the ultimate goal of the project is commercialization, we wanted to be set up for both mobile and stationary applications,” he said. “Economics was the main driver.”

In addition to processing fuel for the diesel engine at the research center, the portable gasifier is intended for field trips to a log home manufacturer in Arizona and a wheat straw particleboard plant in Wahpeton, N.D. Schmidt said that the type of fuel had no significant affect on the gas quality, but moisture content made a difference.

Partners needed to prove commercial viability
Following those promising demonstrations, the EERC is looking for partnering opportunities to prove the commercial viability of gasification-fueled generation. Schmidt receives a few calls a week, he said, “Either from engineering firms trying to solve clients’ problems, or directly from forestry product companies.”

Many wood product manufacturers already use residue for heating, but the gasification process offers a way to dispose of waste year around. The Healthy Forests Initiative could create an important market for portable powerplants, too.

“The government is spending a lot of money to clear undergrowth, and producing tons of residues,” said Schmidt. “The energy market doesn’t pay as much as some industries that process waste into products, but it can handle a much greater volume of material.”

Using waste residue as renewable fuel not only saves landfill space and costs, but reduces emissions from decay and displaces emissions from fossil fuel generation. EERC data indicated that the biomass gas-burning diesel engine emitted far less sulfur than fossil fuels, less NOx and slightly more CO. “That might be taken care of with a catalytic muffler,” Schmidt suggested.

On the road of commercialization, such issues are only potholes. At the end of the line is a new option in self-generation that disposes of waste products, decreases emissions and enhances energy security. EERC and its partners believe that engine generators running on biomass-derived fuel will reach that destination.