Burning Biomass

Are We Overlooking Some of the World’s Sustainable Energy Fuels?

Ever since humans first huddled around a fire for warmth, people have burned logs, straw, wood and animal waste—otherwise known as biomass—to create energy. Indeed, throughout most of history, these crude forms of fuel answered the world’s energy needs. Only after the industrial age matured did people abandon biomass for the modern conveniences and the relatively low costs of power provided by fossil fuels and electricity. Today, with 82 percent of U.S. energy supplied by fossil fuels, biomass appears to be coming back into vogue as one of the top contenders for replacing these finite and polluting resources.

“Global warming issues have forced exploration of bioenergy as an alternative to oil and coal,” says Anders Evald, a research technologist at the Centre for Biomass Technology in Denmark. The center is a national organization that works with other European institutions and companies to research and develop bioenergy products. “Biomass can also include biofuels, gaseous fuels for engines and turbine applications,” says Evald. “The framework under which all this takes place is very, very different from one region of the world to another. Biomass is used in everything from the fireplaces of third world nations to modern steam cycle systems that create both heat and power in industrial countries,” he adds.

Biomass energy is considered a renewable or sustainable energy because of its closed carbon cycle. Since trees use as much carbon dioxide during their growth as they add to the atmosphere when burned, there is no net gain in carbon dioxide—the leading offender of the greenhouse gases.

President Clinton’s 2001 budget includes a new initiative aimed at tripling the use of bio-based products and bioenergy by 2010. For these purposes, the Department of Energy would receive $49 million, and $194 million is slated for the U.S. Department of Agriculture in the President’s proposed legislation.

The U.S. Department of Agriculture has already begun investigating energy crops—such as alfalfa—as a way to increase the nation’s biomass inventory. “Energy crops require less fertilizer and prevent erosion,” says Roger Conway, director of the Office of Energy Policy and New Uses at the U.S. Department of Agriculture. “As a possible income source, these crops can buttress the farm economy, promote rural development and add employment opportunities. And, by using subsidized land for these plants, the resulting crops will reduce the $22 billion the government pays to property owners.”

Farmers in Chariton Valley, Iowa, are growing and harvesting switchgrass on marginal land. The switchgrass will be burned with coal to produce electricity. “Electricity generation is the single largest industrial polluter in the United States,” says Alan Nogee, energy program director at the Union of Concerned Scientists. “One-fourth of the primary emissions that lead to smog, one-third of the emissions that cause global warming and two-thirds of the emissions that contribute to acid rain can be attributed directly to electric power plants.”

By 2020, the Union of Concerned Scientists would like to see 13 to 20 percent of this country’s electricity produced from biomass power plants, says Nogee. Currently, bioenergy resources supply only three percent of U.S. heating and electric power needs.

Transportation fuels offer another application for biomass technology. “Consumers used 100 billion gallons of gas in their vehicles last year,” says Gerson Santos-Lyon, program manager of the Bio-Ethanol Program at the Department of Energy. Vehicle emissions cause 60 percent of the urban air pollution. Biofuels, such as ethanol, can reduce carbon dioxide, ozone formation and carbon monoxide by as much as 90 percent.

“The use of ethanol is both a cost and a supply issue,” says Santos-Lyon. Most ethanol is made from corn, an energy- and labor-intensive row crop. With only 1.6 billion gallons of ethanol manufactured last year, this fuel accounted for just over one percent of total U.S. fuel consumption. Researchers at the National Renewable Energy Laboratory in Golden, Colorado, are investigating ways to use more of the corn plant in the manufacture of ethanol, as well as experimenting with genetically engineered microorganisms to create a pollution-saving fuel from agricultural wastes. The goal of National Renewable Energy Laboratory is to reduce the cost of ethanol from $1.22 per gallon to 60 or 70 cents within a decade, while increasing the fuel’s availability.

Every biomass source has critics and supporters. Even within the scientific community, experts debate the qualities of various biofuels, the consequences and benefits of a managed forest, and the ethics of genetically modified crops. Ethanol has become a political football, the subsidies for which are fiercely defended by Midwestern farmers and farm-state politicians.

“There is a potential for abuse in creating energy from biomass,” says Wenonah Hauter, president of Public Citizen’s Critical Mass Energy Project. The project, founded by Ralph Nader, works to protect America’s natural resources by promoting renewable and energy-efficiency technologies. “Logging old-growth forests would be unacceptable, as is burning municipal solid waste,” says Hauter.

In addition to the direct burning of municipal solid waste, one of the most controversial sources for biomass is landfills. By their nature, landfills produce methane, which when left untreated presents an environmental hazard. When efficiently burned, however, the gas becomes mostly water and carbon dioxide.

“Depending on the composition of the landfill or the municipal solid waste, certain toxic contaminants enter the atmosphere when this type of biomass is incinerated,” says Mike Ewall. Ewall is the director for the Green Energy Leadership Team at the Pennsylvania Environmental Network. These pollutants should be removed and treated with a non-burn technology before the waste or methane is combusted, he adds.

“Even in a best case biomass scenario, releasing the same amount of carbon dioxide as was used during the growth cycle of the organic matter does not decrease global warming,” says Ewall. The quantity of this greenhouse gas in the atmosphere simply remains the same.

Despite these objections, most experts agree that, with some additional guidelines, the exemption of a few categories and one or two new technologies, biomass can be part of a greener power portfolio for this country.