Page 18 - Academic Press Encyclopedia of Physical Science and Technology 3rd BioTechnology

P1: GNH 2nd Revised Pages
Encyclopedia of Physical Science and Technology EN002G-61 May 19, 2001 19:33

Biomass, Bioengineering of 143

FIGURE 1 U.S. land required for biomass energy.

Increasing biomass yields is a crucial area for research. to our total use of energy from all forms. At this effi-
We have invested much effort and money in increasing ciency, about 10% of our land area, or 100 million acres,
the yields of grains such as corn. Average per acre corn would be required to produce the energy equivalent of all
yields increased at a rate of over 3% per year between of the petroleum we use. This is roughly equal to the land
1950 and the present: corn yields were about 28 bushels currently in hay production (60 million acres) plus land
per acre per year in 1947 and topped 127 bushels per idled under government programs. Obviously, other in-
acre per year in 1997. However, we have done compara- puts in addition to solar energy are required for biomass
tively little genetic or agronomic research to increase the production. Nonetheless, these statistics gives some idea
yields of the perennial grasses and tree crops on which of the potential to meet our energy needs from biomass.
a sustainable biomass processing industry will likely be Figure 1 summarizes some of figures for U.S. land area us-
based. Thus there is great room for improving these age and the area required to equal our energy usage at solar
yields. energy conversion efficiencies typical of corn and sugar
Biomass is currently the most practical collector we cane.
have of solar energy on a large scale. The solar energy in-
cidentontheUnitedStateseachyearisabout600timesour
3. Comparison of Biomass and Petroleum
annual energy consumption of about 95 quads (one quad
equals one quadrillion BTU or one million billion BTU). Worldwide consumption of crude oil, a large but nonethe-
The higher the biomass yields, the more solar energy is less limited resource, was about 27 billion barrels per year
collected per unit land area. At a solar energy conversion in 1999 or about 4 billion tons, with an approximately
efficiency of 0.8% (corn efficiency), approximately 40% equal amount of coal consumed. As mentioned earlier,
of the U.S. land area placed in continuous crop produc- total production of new biomass, an indefinitely renew-
tion would produce biomass with an energy value equal able resource, is approximately 150 billion tons per year.