ike driving, access to energy is a privilege. A third of the
world lives without any access to electricity at all, although
they are not thereby spared the effects of climate change. By
comparison, the U.S. with just 6% of the global population uses
30% of the world's resources. The kinds of lifestyle choices
each of us make every day have implications that reach far beyond
our daily lives and our homes.
The implications of our decisions are often astounding. Let's
take our morning buddy coffee as an example: by purchasing organic,
shade-grown coffee that has been certified as "fair trade",
we do more than ensure a pesticide-free product that has been
sustainably harvested to the benefit of migrating birds; we
support the families of the local farmers who grow the coffee.
Electricity has similar ripple effects. When it comes to energy
use, making the right choices starts with taking a look at what
you do and don't use. Some people seem to equate the term "energy
conservation" with walking around in the dark with three sweaters
and a down-filled coat. If you want to go all the way, be our
guest, but we dispel many misconceptions on our web site Learn
to Conserve. Check it out. You'll find tons of surprising
ways you can save electricity-and money-without sacrificing
your comfort or quality of life.
Renewable
energy is here to stay, and there are more options
than ever before.
There are a variety of renewable energy sources that are
being used to generate electricity on large and small scales,
including Geothermal,
biomass,
hydropower,
and hydrogen
(which we'll explore in Transportation), but we are focusing
our attention here the cleanest, most currently available sources.
SOLAR ENERGY: LOOK UP
Energy from the sun's light has made life here on Earth possible,
not only in sunny California but also in Iceland, Australia,
and Illinois. Solar energy can be collected and stored to generate
electricity, provide hot water, and to heat, cool, and light
commercial buildings, factories, and homes — and it does so without
creating air pollution, destroying habitat, or impairing human
health. Just as the sun provides essential support for our ecosystems,
sunlight also provides enough energy to run a home in Pittsburgh
or Berlin, and many other parts of the world.
In its simplest form, solar energy can be used passively
to heat buildings. Sunlight passing through large south-facing
windows is absorbed, stored and slowly released when it is needed
at night. Solar water
heating systems use collectors, mounted on building
rooftops facing the sun. Sunlight heats an absorber plate in
the collector, which, in turn, heats the fluid running through
tubes within the collector. Heated water is either pumped or
gravity-fed to a storage tank, where it rests until used.
Photovoltaic
(PV) cell systems convert sunlight directly into electricity.
PV cells are composed of semiconducting material that absorbs
sunlight. The solar energy knocks electrons loose from their
atoms; the electrons flow through the material to produce electricity.
PV cells are usually made into modules holding about 40 cells,
and modules are mounted into PV arrays. Small PV arrays can
be used to generate electricity for a single building or, when
assembled in large quantities, form a solar power plant.
SOLAR ENERGY: WORLDWIDE RAYS
A quick scan of the globe for solar panels and absorber plates
indicates that the biggest opportunity for solar power lies
in the developing world. An estimated two billion people are
not connected to a power grid, and for the majority, the grid
is unlikely to arrive in their remote communities anytime soon.
Solar energy provides the most cost-efficient source of electricity,
and of the one million homes that use solar as their energy
source, most are located in developing countries.
Research shows that many of our daily tasks could be completed
using solar energy. Since it has started gaining a foothold
in the worldwide market (industrialized countries have finally
begun to embrace solar), costs have decreased. PV installation
sales grew 37% in 2001 over 2000; in 2002, the United States
had the fastest growing market, with residential installations
of solar collectors and PV systems more than doubling over the
previous year.
SOLAR ENERGY: RENEWING AMERICA
In Fall, 2002, students from universities all over the nation
converged on the Mall in the Nation's Capitol to demonstrate
that solar energy is not a far-off fantasy, but that it's available
now and is very much here to stay. They were taking part in
the first-ever Solar
Decathlon and they had a mission: to design, build,
and operate the most livable and efficient solar-powered house.
GreenWorks followed the team from Pittsburgh's Carnegie Mellon
University as they designed and built an inner city townhouse
and put it to the test. |
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WIND ENERGY: STEADY BREEZE
Incredible as it may sound, electricity can be generated by
a wind gust blowing a steady 10 miles per hour or higher. Wind
turbines work in similar fashion to hydroelectric turbines:
flowing air (rather than water) spins the wind turbine rotor,
and the rotor in turn drives the shaft of an electric generator.
Since wind is far less dense than water, for a wind rotor to
generate the same amount of electricity as a hydro turbine,
it must be much larger. A hydro turbine capable of generating
one megawatt (MW) of power may be several feet in diameter,
while a 1-MW wind turbine's rotor would be roughly 175 feet across.
According to The American
Wind Energy Association —
WIND ENERGY: WORLDWIDE WIND
Taking a look around the world for wind mills, you'll find most
of them in Europe. European
countries have pioneered the development and use of
wind-based energy, with a growth rate of 40% a year. Germany
is the world leader in wind-generated electricity, boasting
more than one third of the world's total. The United States
is ranked second, followed by Spain. Denmark, ranked 4th, gets
18 percent of its total annual electricity from wind, exhibiting
the highest per capita use in the world.
Wind energy can satisfy many of our electrical needs. A
1999 study ( PDF File, Acrobat
Reader required ) by Denmark's BTM Consult for the
European Wind Energy Association and Greenpeace found that by
the year 2017, wind could provide 10% of world electricity supplies,
meeting the needs of 500 million average European households.
Sixteen countries, including China and India, had entered the
fast-growth phase in wind power development by early 2002, representing
half the world's population.
WIND ENERGY:
BLOWING ACROSS AMERICA
Despite some impressive steps towards sustainable energy sources,
only a tiny fraction of wind's potential has been utilized so
far worldwide. The amount of power generated by wind grew just
3 percent in the US in 2001, and although we are the second
largest producer of wind-based energy, most of the potential
has remained virtually untapped. Studies estimate that development
of just 10% of the wind potential in the 10 windiest States
would provide more than enough energy to reduce total domestic
emissions of carbon dioxide by almost a third and world emissions
by 4%.
The Pacific Northwest Laboratory's 1991 study An
Assessment of the Available Windy Land Area and Wind Energy
( PDF File, Acrobat
Reader required ) in the Contiguous United States did
not list Pennsylvania in the top twenty states for wind energy
potential, but the Keystone State is clearly a pioneer in wind
energy in eastern United States. Wind
power generators account for 34 MW of electric capacity
in Pennsylvania, and an additional 80 MW are planned. Pennsylvania's
higher education institutions purchase more energy from renewable
sources than anywhere in the nation. Radnor township, a suburb
near Philadelphia, recently announced that it is going to purchase
62% of its electricity from wind generated electricity, making
it the nation's leading wind energy purchaser among municipalities.
WIND ENERGY: CONTROVERSY
Despite its many virtues, wind-energy is not something that
everyone gives unequivocal support. The National Audubon Society
has opposed wind farms based on the potential hazard that turbine
blades pose to migrating birds. Other criticisms come from residents
and people in the tourism industry near wind farm sites, who
bristle at the noise made by turbines and the impact they have
on views. The controversy
surrounding attempts to gain approval for a wind generating
facility off the coast of Cape Cod is a good case in point.
For more on At Home visit our links
and resources page.
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