Using ag biomass for energy isn’t free

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UNIVERSITY PARK, Pa. – Using agricultural byproducts as an energy source these days is making more economic sense, according to a fuels expert in Penn State’s College of Agricultural Sciences. But “biomass” is not free, he points out.

It’s not free. “We have the opportunity to use biomass – generally defined as organic matter including wood, agricultural crops, crop residues and animal manures – to produce several types of fuel,” said Dennis Buffington, professor of agricultural engineering. “But we can no longer think of these materials as free.”

Although energy prices have stabilized this year, there are increased concerns about the price and availability of energy in various forms, notes Buffington.

“Just one year ago, we were facing energy prices of over $2 a gallon for gasoline, natural gas prices approaching $25 per 1,000 cubic feet and home heating fuel of $1.40 a gallon in some markets,” he said.

Reducing vulnerability. “Considering the terrorist attacks last September and the continuing terrorist threats, we are now even more committed to reducing our vulnerability to world events by decreasing our dependence on imports of overseas petroleum.”

Examples of biomass include ethanol produced from shelled corn, biodiesel from organic oils (derived from plants, animals and spent cooking oil), methane from digesting animal manures, ethanol from “cellulosic” plant materials and methane from landfill gases.

More benefits. There are benefits in addition to the fuels produced, including byproducts that often can be used for animal feed, organic fertilizers and soil amendments, points out Buffington.

And there is always the potential for creating jobs and spurring economic development in the communities where these processing facilities are located.

“Unfortunately, many analyses of the economic benefits of producing ethanol from cellulosic plant materials often regard the cellulose as free,” he said.

“Whether we are talking about straw, corn stover, corncobs or other crop residue, these materials are anything but ‘free’.”

Expenses. Obvious expenses, according to Buffington, include the labor, equipment and fuel costs for harvesting these biomass materials, transporting the low-density materials to a central facility for producing the fuel and storing the materials for use in off-season.

“Less obvious expenses include increased soil compaction because of more equipment traffic on the fields, increased soil erosion because of the loss of vegetative cover, increased need for fertilizer and herbicides for the next cycle of crops, decreased moisture-holding capacity of the soil, and decreased food and shelter for wildlife,” he said.

“Obviously it’s difficult to place dollar values on indirect costs of utilizing crop residues, such as soil compaction, soil loss and wildlife habitat,” Buffington adds. “Direct costs of utilizing crop residues can be established for factors including labor, equipment and fuel.”

Producers also need to consider that the crop residue has an opportunity cost from other competitive uses such as livestock bedding, landscape mulch, fiberboard and insulation.

“In all analyses, we must always include the economic costs and the environmental implications associated with utilizing crop residues to produce fuel,” said Buffington.

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