Geography Reference
In-Depth Information
Perennial resources
are theoretically eternal. While they offer great promise, all have current
limitations that relate directly to geography. Here are four examples.
Solar energy
Although astronomers tell us the sun will eventually burn out, for all intents and purposes, it is an
eternal, perennial source of power. Energy from the sun can be absorbed directly by solar panels and
puttouseforheating. Evenbetter,however,are
photovoltaic cells,
whichconvert sunshinetoanelec-
trical current. The sun is fickle, however. Some days it shines and some days it does not, so a major
engineeringproblemishowtostoresolarelectricity fromsunnydaystocarryusthroughcloudydays.
Also, knowledge of climates informs us that solar intensity varies around the world (see Chapter 9).
Unfortunately, areas of maximum energy need often occur where the sun is comparatively weak (or
often obscured) and vice versa. Thus, solar and other energy sources that possess a measure of unreli-
ability probably should not be looked to as complete solutions to future energy needs. Better perhaps
that we view them as parts of a resource menu from which different resources can be called upon as
conditions permit.
Wind energy
Wind is physical energy that can be harnessed to produce electricity. This is achieved by constructing
rather specialized windmills that are tall poles (or stanchions) fitted with a propeller (actually a tur-
bine) at the top. When the wind blows, the propeller turns. This rotating motion is linked to and op-
erates a generator that produces an electrical current.
Wind is a by-product of sunshine (see Chapter 9); and because solar energy is a perennial source of
energy, wind power is categorized as the same. But like the sun, wind is fickle. Some days it blows
and some days it doesn't. Accordingly, for wind to become a major contributor to energy production,
means must be found to store surplus wind-energy from windy days for consumption on calm days.
Also, some places are inherently windier than others. Coastal areas, for example, tend to be particu-
larly breezy because water and land absorb sunshine at different rates. Mountain and foothills areas
also are especially favorable.
Given present technology, a single windmill provides sufficient energy for only a limited number of
consumers. Hundreds would be needed to provide for the needs of a small city. And indeed, in some
