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Unit 12: Alternative Energy Page 16 of 31
area to gather enough sunlight to Energy From Biomass
run a 100-watt light bulb.
Fossil fuels, which include
Solar energy is still more expensive petroleum, natural gas, and coal,
than other methods of generating supply nearly 90 percent of the
electricity. However, the cost of energy needs of the United States
solar electricity has greatly and other industrialized nations.
decreased since the first solar cells Because of their high demand,
were developed in 1954. these nonrenewable energy
resources are rapidly being
It has been proposed that panels of consumed. Some estimates
solar cells on satellites in orbit suggest there is only a SOD-year
above the earth could convert solar supply of oil and natural gas
energy to electricity twenty-four remaining on Earth. Coal supplies
hours a day. These huge solar are expected to last about a
power satellites could convert thousand years.
electrical energy to microwaves
and then beam these microwaves We must find other sources of
to Earth. At the earth's surface, energy to meet the increasing fuel
tremendous fields covered with demands of modern society.
antennas could convert the Important alternate sources of
microwave energy back to energy include: solar, wind,
electricity. biomass, hydroelectric,
geothermal, nuclear, and tidal
It would take thousands of energy.
astronauts many years to build
such a complicated system. One of the benefits of using
However, there are many practical alternate sources of energy is that
uses of solar energy in use today. many of them are "clean." This
These uses include heating water, means that they do not cause
heating and cooling buildings, pollution. Also, many alternative
producing electricity from solar energy sources are renewable
cells, and using rain and snow from energy sources. They are replaced
the water cycle to power electrical naturally-such as plant life-or are
generators at dams. readily available - such as the sun
and wind. In addition, the use of
renewable forms of energy will
allow us to stretch out our current
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