Biomass Power 2002

Article excerpt

More than any other energy resource, plants, with their stored solar energy, are particularly well suited to meet the nation's energy, environmental, and economic needs.

Plants are the masters of capturing the sun's energy into conveniently stored forms--sugars, fats, and proteins--that power and construct almost all life forms, including humans. Although our bodies are exquisitely tuned to extracting and using the solar energy carried in plant and animal matter, our technologies for extracting and using plants' stored solar energy, in comparison, have been clumsy and primitive at best. Nonetheless, plants, called biomass in the energy industry, are already the second-largest source of renewable energy after hydroelectric power.

From the energy industry's viewpoint, biomass is essentially stored solar energy that can be converted to heat, electricity, fuel, or chemicals. Increased use of biomass for energy would reduce greenhouse gas emissions, lessen dependence on foreign oil, improve the U.S. balance of trade, boost the rural economy, and support a major new American industry. More than any other energy resource, biomass is capable of simultaneously addressing the nation's energy, environmental, and economic needs.

Biomass power is the generation of electric power from biomass resources--usually urban residues, crop and forest residues, and crops grown specifically for energy production. Compared with fossil-fuel- based electricity, biomass power reduces emissions, including greenhouse gases, because biomass removes carbon dioxide from the air as it grows. In this way, the entire biomass cycle of growing, converting to electricity, and regrowing biomass can result in very low net carbon emissions. Through the use of residues, biomass power systems can even represent a reduction in net greenhouse gas emissions by avoiding methane emissions that would result from sending unused biomass to landfills.

Deployment today and tomorrow

Most of the nearly 1,000 biomass power plants in the United States are direct combustion facilities; that is, they burn biomass to release its energy as heat. About two-thirds of these plants provide electricity and heat on-site for industrial processes. More than 75 percent of this on-site power is generated by the forest products industry from its own wastes. Grid-connected biomass power plants, which produced less than 2,000 megawatts in 1978, produced more than 7,500 megawatts in 2000. Overall plant size averages 20 megawatts, with a biomass-to-electricity conversion efficiency of about 20 percent. In addition, the biomass power sector includes about 3,300 megawatts of generating capacity that uses gas from municipal solid wastes and landfills.

The cost of generating electricity with biomass ranges from 6 to 12 cents per kilowatt-hour, depending on the feedstock (residues or energy crops). With the development of highly efficient gasification units, the price could be driven down to 5 cents per kilowatt-hour. Recent statistics indicate that the annual average biomass fuel consumption (particularly in the form of firewood and charcoal in developing countries) totaled almost 47 quadrillion Btus worldwide, while U.S. annual average consumption was 3.5 quadrillion Btus.

The United States has the land and agricultural infrastructure available to produce enormous quantities of biomass in a sustainable way. The American Bioenergy Association (ABA) estimates, for example, that the United States could produce enough biomass to replace half of the nation's gasoline usage or all of the nation's nuclear power without a major impact on food prices. Shifting part of the $50 billion now spent for oil imports and other petroleum products to rural America would have a profoundly positive effect on the economy, in terms of jobs created (for production, harvesting, and use) and industrial growth (facilities for conversion into fuels and power). …