Every year, Planet Earth produces a deep well of untapped energy, but it’s not oil.

It’s renewable biomass — plant and animal materials that represent an energy resource of about eight quadrillion British thermal units a year, in the United States alone. That’s a tiny fraction of the estimated 100 quadrillion Btu of energy consumed in this country every year. Still, it’s three times the amount of biomass that the country uses now, according to the University of North Dakota Energy & Environmental Research Center (EERC).

The U.S. Department of Energy estimates that at least 500 million dry tons of biomass are now available annually in this country. American agriculture generates nearly half the total stocks; the wood and forest industries produce another third. Major biomass resources include:

  • Crop residues, 24 percent
  • Municipal solid waste, 21 percent
  • Animal manure, 18 percent
  • Mill waste, 16 percent
  • Forest, urban and industrial wood waste, 14 percent.

Minnesota generates more than 24 million tons of collectible biomass a year, making it the fourth leading biomass state behind Texas, California and Iowa, according to the EERC. Crop residues and manure account for three-fourths of Minnesota’s annual biomass production, and forest and mill waste make up most of the rest. “Minnesota has a lot to offer in the way of biomass feedstocks,” says Al Doering of AURI’s coproducts lab in Waseca.

The state’s biomass resources include:

Crop residues, 13.2 million tons Manure, 4.5 million dry tons Forest, mill, and urban wood waste, 4.4 million tons Municipal solid waste, 2.3 million tons

Today, the U.S. uses biomass to produce about 2 percent of its total energy. Wood and crop residues are burned as fuel for steam-and-electricity cogeneration in the industrial and ag processing sectors. The electricity industry also cofires wood and other biomass for power generation, often in conjunction with coal. And increasingly, crops such as corn and soybeans are being converted into liquid transportation fuels — ethanol and biodiesel. The Energy Information Administration’s 2006 Annual Energy Outlook projects that biomass electricity generation will double over the coming decade, to about 50 billion kilowatthours by 2016. That’s about one percent of the projected 4,807 billion kilowatt-hours of total generation.

In this country, biomass-energy use has been low because of cheap fossil fuels, Doering says. Feedstock cost is a main barrier. Biomass’s energy value is low per ton, and it is thinly distributed across a wide area, making it expensive per Btu to collect and transport. Costs range from $30 to $60 per dry ton, according to EERC estimates.

The federal government has set a goal of developing a biomass collection industry capable of delivering one billion metric tons of biomass fuel a year by 2050. The near-term target is 150 million metric tons a year by 2010, at a price of $30 per ton or less. AURI and others are working on efficient methods to harvest, transport and store biomass feedstocks, Doering says. “As fossil fuel prices increase and the cost of handling biomass commodities decreases, their use as energy becomes feasible.”