Cooperative Living March/April 2018 - 26

CloserLook | by Paul Wesslund, Contributing Writer
Where renewable energy
gets its power
S
olar energy and wind power may
not seem like a big deal. Unless
you're talking about the future.
Or maybe even the present.
For all today's talk about renewable
energy, it still makes up a pretty small
portion of the energy sources that
generate our electricity. But it's coming
on fast, and it's picking up speed.
Here's your crash course in how wind,
the sun and water generate electricity.
Solar Energy
Solar energy generates only about 1
percent of the nation's electricity, but
that's a stunning increase from just five
years ago, when the number was too
small to report for the U.S. Department
of Energy. Solar growth will continue
as costs fall, technology improves and
people figure out better ways to use
solar energy.
There are lots of ways to use energy
from the sun. You can hang your washed
clothes outside to dry, and you can open
curtains to warm your home on a sunny
day. More ambitious projects use the
sun to warm pipes full of water that is
pumped around a building for heat.
But what most people mean when
they talk about solar energy is
photovoltaic electricity. When certain
materials get hit by sunlight, their
atoms spit out an electron, and
electricity is just a stream of electrons.
Over the decades, scientists and
engineers experimented with solarsensitive
materials to make them into
lighter, longer-lasting and more
affordable wafers called photovoltaic
cells, which are combined and integrated
into solar photovoltaic modules. One
of their first uses was in space travel,
and continued improvements are
allowing solar to become a more downto-earth
kind of energy.
One of those improvements is cost. Solarpanel
prices dropped 85 percent in the past
24 | Cooperative Living | March-April 2018
seven years with improvements in materials
and larger-scale production methods.
Another technological advance is
about to give the industry an extra
boost, says Dale Bradshaw, a technical
consultant with the National Rural
Electric Cooperative Association
(NRECA). He says solar panels can now
track the sun as it moves across the sky
rather than sitting fixed in place, raising
their productivity by collecting more
sunlight throughout the day. This year,
the U.S. Department of Energy's Energy
Information Administration reported
that half the large solar installations in
the country already use some kind of
sun-tracking technology.
It's also worth knowing that the solar
industry is maturing with different forms
of ownership: utility, industrial,
commercial and residential scale, and
community solar installations.
Utility scale is what you might expect
- large banks of solar panels owned and
operated by an electric utility or other
large organization, producing many
megawatts of solar energy. Industrial
and commercial solar installations can
range from kilowatts up to multimegawatts
and be placed on rooftops,
over parking lots or on land near
industrial and commercial enterprises.
Industrial and commercial installations
are beginning to increase as the price for
solar continues to drop. Residential solar
installations are also being installed
primarily on rooftops, especially in the
southwestern United States.
NRECA's Bradshaw says community
solar can ease the higher expense of selfowned
rooftop solar. With community
solar, a utility builds a large solar
installation and sells shares in the
project to customers interested in an
investment in renewable energy. That
style of ownership and development is
especially suited to consumer-owned
electric co-ops, and many are offering
Here are the basics of a
small but fast-growing source
of your electricity.
solar shares to their members.
" Co-ops are doing a great job of
building community-scale solar, " says
Bradshaw. " They're going full blast
on that. "
Bradshaw also notes that community
solar allows a homeowner to avoid both
maintenance of their own system, and
the hassle of sorting out different offers
from rooftop solar vendors.
Wind Power
Wind power has increased
significantly as costs continue to
decrease. Wind power generates nearly 6
percent of the nation's electricity, and it
is growing at a pretty good clip, with an
increase of about 35 percent during the
past four years.
In a way, wind generates electricity
the same way as coal, natural gas and
nuclear - by spinning a turbine that
creates an electricity-producing magnetic
field. The huge difference is that the
turbine is turned by enormous propellerlike
blades designed to catch the wind.
It's the size of those blades and the
height of the turbine towers (as much
as 300 feet in the air) that make the
difference, says NRECA's Bradshaw.
" Wind is a really useful renewable,
but it has to be utility scale, " he says.
A tall utility-scale tower can capture
as much as 50 percent of the wind,
but there's not a practical, personal
alternative to compare with rooftop
solar. A rural residential customer or
a rural commercial customer with a
50- to 100-foot tower will probably
generate electricity only about 25
percent of the time. " It's really not
cost-effective for small-scale home use
when compared to utility-scale wind
turbines, " says Bradshaw.
Hydroelectric Power
Another way to turn an electricitygenerating
turbine is to store water
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Cooperative Living March/April 2018

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