tall, located along the border of Walla Walla County, Washington, and Umatilla County,
Oregon. The electricity generated by this wind farm is sufficient for 70,000 homes. Many
areas of the world, including parts of Alaska, Canada, the Scandinavia, and Russia have
strong, consistent winds favorable to the development of wind energy.
Figure 6.11. Wind-powered electrical generators mounted on towers are becoming increasingly common
sights in the world in areas where consistent wind makes this nonpolluting source of renewable energy
practical.
Biomass Energy
As noted earlier in this chapter, photosynthesishν
6CO 2 + 6H 2 O → C 6 H 12 O 6 + 6O 2 (6.8.2)enables the conversion of solar energy to chemical energy in the form of biomass.
Photosynthetically generated biomass is the source of food energy for essentially all
organisms and, until about 200 years ago, was the source of most fuel, which it still is
in parts of the world. Today, Finland gets about 15% of its energy from wood and wood
products. A large fraction of this energy comes from burning the black liquor byproduct
from pulp and paper manufacture, which uses wood as a raw material. As shown in Figure
6.6, photosynthesis suffers from the disadvantage of having less than 0.5% efficiency in
the conversion of solar energy to chemical energy. However, some plants, most notably
sugarcane, convert solar energy to biomass energy with an efficiency of around 0.6%.
As shown in Reaction 6.8.2, carbohydrates, such as glucose, C 6 H 12 O 6 , are produced
by photosynthesis. They can be burned directly, converted chemically to other fuels, or
fermented to produce ethyl alcohol fuel. Hydrocarbons are more desirable as fuels, and
some plants produce them directly. One example is the Philippine plant, Pittsosporum
reiniferum, the fruits of which contain such a high content of hydrocarbon terpenes,
Chap. 6. Energy Relationships 153