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Green Project Terminology: The Language of the Green Wave • 31

the sun or other stars are responsible for ALL our energy. Even nuclear
energy comes from a star because the uranium atoms used in nuclear
energy were created in the fury of a nova—a star exploding.” Solar water
heating has been utilized in the United States since the 1890s. “In 1897, 30
percent of the homes in Pasadena, just east of Los Angeles, were equipped
with solar water heaters. As mechanical improvements were made, solar
systems were used in Arizona, Florida and many other sunny parts of the
United States.” We are most interested in the application of the genera-
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tion of solar thermal electricity. Huge solar panels collect sunlight to heat
water, producing steam to run electricity-generating turbines. One of the
downsides is that electricity cannot be generated during cloudy days, thus
triggering larger projects like DESERTEC, featured in Chapter 4.

geothermal

Geothermal is using heat from within the earth. Geothermal energy is
one of what we consider the more interesting renewable energy sources
because one of the authors has a background in geology. There are a couple
of ways to utilize earth to produce geothermal energy. One is using deep
wells to tap into superheated water or steam and pumping that to the sur-
face for heating purposes or to run turbines to generate power. The sec-
ond is to use stable temperatures closer to the surface. During the 1950s,
we used to “drive” wells to use for watering lawns, rather than using the
more expensive town water. What we found was that the water was a con-
sistent 52° in temperature, a nice refreshing temperature in the summer.
So how does 52° water help save energy? The water is already “heated”
or “cooled” to 52°, therefore requiring less energy to heat it or cool it to
the desired temperature than the winter water, which may be close to 32°,
or the summer water, which may be at 80° or more. The method used to
heat and cool the water is through a geothermal heat exchanger, in most
cases a ground source heat pump that exchanges warmth or cooling from
the earth. We will not take up your time detailing how heat exchangers
work; just suffice it to say it is a more efficient method than air-sourced
heat pumps or electricity. One caution, however, is that the initial start-
up costs including the equipment are greater than the more conventional
methods. However, it is possible to justify the added cost with a longer
payback period and overall energy savings. And remember that geother-
mal energy does not have only to do with water. By building underground
and taking advantage of the constant temperature of about 56°F and the