Energy from biomass -- such as grain, grass, or wood -- probably can meet 10 to 20 percent of US energy within 20 years, says a major new study. But there is no easy road to this benefit. Unless great care is taken, rapid development of this new energy supply could seriously damage the environment.
This is the main conclusion of an analysis by the congressional Office of Technology Assessment (OTA).
Responding to the growing national interest in gasohol, wood fuel, and other forms of what it calls "bioenergy," the OTA also notes that this promising energy option still has low priority in the Departments of Agriculture and Energy. "Vigorous policy support" is needed to realize substantial bioenergy payoff -- support that "could take the form of economic incentives to accelerate the introduction of bioenergy and to promote the establishment of reliable supply infrastructures."
In other words, the United States needs to build up the kind of integrated supplier-user system for bioenergy it now has for oil. This includes develop ing markets for various biomass fuels as well as evolving complex delivery networks so these fuels are as easy to get as are coal, gas, and oil today.
It also means designing equipment to use the new fuels, as some motorists have discovered when the ethanol in gasohol has attacked nonresistant parts of automobile fuel systems.
Bioenergy today accounts for a little under 2 percent of US energy supply -- mostly through wood burning. In units of the Quad -- a quadrillion Btus -- that comes to about 1.5 Quads a year. By A.D. 2000, OTA estimates, bioenergy in various forms could supply as many as 12 to 17 Quads annually. That would amount to 10 to 20 percent of the energy supply, depending on the total energy use anticipated. The OTA notes that the Department of Energy projects annual consumption of 120 Quads in 2000; but conservation could cut that to 90 Quads a year or less.
Besides burning wood, grasses, or crop residues directly, or turning them into alcohol, biomass can be gasified to produce what someone has dubbed "unnatural natural gas." Many forms of plant material can be used -- including animal manure. However, as the study points out, much of this raw material or the land needed to produce it already has other uses. Diverting these resources to energy production means choosing among benefits.
The issue has already arisen in the grain-for-food-or-fuel controversy. Some observers, such as the World watch Institute, have warned that diverting grain for fuel could cut into the world's food supply. Gasohol boosters have claimed, on the other hand, that alcohol production leaves a nutritious residue. The OTA notes that the residue, while nutritious, is no substitute for grain as food. It is more a substitute for high-protein feed supplements such a soybeans. Furthermore, it takes 30 to 40 percent more land to get a given amount of protein concentrate via the grain-alcohol route than to get it directly from soybeans.
Similar choices of resource use will arise making fuel from forests or crop residues. For example, OTA agrees with those soil experts who have questioned the wisdom of diverting "waste" material that now decays to enrich soils. This could be a particularly serious problem in forests inten sively managed for energy production.
Soil depletion is part of the larger question of environmental side effects of a bioenergy industry. The OTA warns that careless development of such an industry could be environmentally dangerous. It could cause substantial air pollution -- not only by such obvious agents as smoke from wood stoves, but by effluents from biomass conversion plants. Forests could be "mined out" by thoughtless wood cutting. Pressures to produce more fuel could open marginal lands to cultivation when these lands might better be left alone. Massive erosion and land deterioration could result, the OTA warns.
In short, OTA sees biomass as a new energy source ripe for rapid development. But in doing this, the US should realize that it is developing an new energy use and supply system that will have to compete with other systems and whose many side effects should be carefully considered.