| Green Living
Healthier, More Environmentally Friendly Alternatives
What's not to love about solar power? It's free, clean,
and available every day. And you don't have to live
in California or the Australian outback to harness
the power of the sun. The costs of solar systems have
come down 80%+ over the past two decades, and as more
consumers take to solar the costs are falling still.
There are a variety of solar power options available,
and it's important to understand the benefits and
costs of each option.
How Solar Power Works
Solar power is produced by using photovoltaic (PV)
cells to capture the energy of the sun and convert
it into electricity. The basic unit of the system
is the solar cell, which are connected together into
modules. PV cells are comprised of semi-conductors,
most often made of silicon (like the chips used in
computers). The semiconductors absorb power when they
are struck by light. These modules or panels of PV
cells are what you see installed typically on the
roofs of homes and businesses. The electricity created
by the solar system is DC or direct current, and the
electricity we use in our homes is AC or alternating
currents. Thus solar systems include an inverter which
changes the DC current into useable AC current. Installing
solar systems is a complicated technical process and
most people will benefit by using contractors skilled
in solar technology and electrical installation.
Home Solar Power Systems
There are two main forms of solar systems for residential
use: the “grid-tie” system and the “off-grid”
or stand-alone system. In a grid-tie system, a home
has solar cells but is still connected to the local
power grid. The home solar system includes solar cells
installed on or near a home that collect the sun's
energy and convert it into DC electricity. Then the
inverter converts the DC power into AC power, which
can then be used directly in your home.
Electricity produced by the solar cells that is not
used immediately in the home is returned to the power
grid. When this happens your electricity meter literally
spins backwards as you are passing energy to the grid.
You are also building a credit on your power bill.
This is called “net-metering”. The benefit
of the grid-tied system is that it does not include
expensive batteries to be installed in your home for
the storage of power; the grid acts as the storage
system and your home and the grid exchange power as
you need and produce it.
Off-grid or stand-alone systems are typically used
in remote locations where standard grid-based power
is not available. These systems are more expensive,
but do allow for complete electrical independence.
These systems require deep-cycle batteries for storing
the electricity as well as a charge controller to
assure the flow of electricity from the cells does
not over-charge the batteries.
For a solar system to work well it needs an unobstructed
view of the sun. In the United States, typically the
best orientation for solar panels is to the south
as the sun is in the southern half of the sky (lower
in the winter and higher in the summer).
Solar panels can either be attached directly to a
slanting roof, or bolted onto frames on flat roofs.
If your roof is not a good option, then panels can
also be mounted on the ground. They can either be
placed on a fixed mount frame or on a “tracking
mount” that follows the sun across the sky.
Solar Water Heaters
A solar water heating system is fairly simple. You
install solar panels, typically on your roof, and
the sun heats the panels. Then these solar collectors
heat a fluid in pipes held in the interior of the
panel boxes, and that fluid is transported into the
house where it heats water in a storage tank. The
system can include a pump which circulates the transmission
fluid from the roof to the water tank and back again,
but pumpless systems are also available. In areas
where freezing isn't an issue, systems can heat your
water directly. In most places a type of antifreeze
is used and the fluid and water do not mix.
One convenient and less expensive option if you live
in a warm climate is a solar batch collector. Water
is simply pumped up to a solar storage tank on the
roof and heated by the sun. Then you just use the
hot water as needed. (But you need to make sure you
have a roof that is strong enough to support the weight
of the stored water and the tank.) These units cost
less than $1000. Another great way to save energy
and money if you are a pool-owner is to use solar
power to heat your pool.
Solar Power Costs
The cost of a solar system depends on the size of
your home, the orientation of your property, and your
electricity needs. But for a standard medium-size
house it can run from $20,000-$40,000 before rebates.
However, many state and local governments offer incentives
for solar installation that can significantly reduce
the costs. Rebates coupled with federal tax credits
can knock thousands off of your initial investment,
sometimes cutting it in half! Be sure to check with
your local government for these offers.
One way to cut the cost of a solar electric system
is to reduce your electricity use before installing
the system. Such measures as replacing light bulbs
with compact fluorescents and upgrading old appliances
can cut your electricity use (and also your solar
investment) in half. You'll spend a bit of the savings
on the new items, but you'll have that brand new stainless
refrigerator you've been craving too. Low Impact Living's
In-Home Environmental Assessment program will help
you understand what cuts can be made before you go
solar and therefore save you thousands of dollars.
You can also finance solar installation using home
equity. This approach offers the possibility of making
you “cash flow positive” from day one,
especially if you live in an area that has high power
prices, good exposure to the sun, and solid local
If the cost of a full house solar system is daunting,
a very attractive option can be heating your water
with the power of the sun. A solar water heating system
will save a typical California family $1000 in power
costs. The payback period on these units is typically
under five years.
Other great lower-cost solar options are distributed
solar applications. You can get attractive solar lights
to illuminate your yard or garden. You can also power
a nice fountain or heat your pool using solar energy.
Wind power is clean, plentiful and the world's fastest
growing source of energy. Countries like Germany, Denmark,
Spain and India are becoming major users of wind energy.
While it has been slower to catch on in the U.S., you
can see major wind farms in the American Southwest.
But American farmers and rural residents have known
for a long time that harnessing the power of the wind
makes sense. And if you have the space and vertical
clearance, you can also take advantage of wind power
to lower your emissions and power bills.
How Wind Power Works
Wind turbines capture the wind's kinetic energy to power
a generator that produces electricity. Wind generators
have four main parts: blades (also known as rotors),
a power shaft, gears and a generator. The wind drives
the blades, which turns the shaft, which powers the
generator and electricity is produced.
Installing wind systems is a complicated technical process
and most people will benefit by using contractors skilled
in wind technology and electrical installation.
Home Wind Power Systems
Consumers can purchase wind units for home use. There
are medium-size units that can fulfill all of the electric
needs of a home, or smaller units that can be used as
a supplemental power supply. A wind system typically
lowers a home's electric bill by 50-90% depending on
the size of the system and the wind patterns of the
Wind power systems are most practical in rural areas
or for consumers with an acre or more of land. But check
with your neighbors and local zoning laws – you
may be able to set up a small system in a suburban area.
Depending on the size of your site and your energy consumption
patterns, you’ll likely need a turbine rated in
the 5-15 kilowatt range to make an impact on your energy
As with solar power, depending on where you live, you
can either use a “grid-tied or a stand-alone system.
In a grid-tie system, a home uses a wind power system
but the house is still connected to the local power
grid. The electricity produced by the wind system that
is not used immediately in the home is returned to the
power grid. When this happens your electricity meter
literally spins backwards as you are passing energy
to the grid. You are also building a credit on your
power bill. This is called “net-metering.? The
benefit of the grid-tied system is that it does not
include expensive batteries to be installed in your
home for the storage of power; the grid acts as the
storage system and your home and the grid exchange power
as you need and produce it.
A stand-alone system requires greater power-generation
capacity and large storage batteries. These systems
are significantly more expensive, but they do give you
total energy independence.
The most important thing to consider is the average
wind speed of your site. In general people living in
coastal areas or in the Great Plains of the U.S. are
the best candidates for wind power. If you want to measure
this yourself, you’ll need a wind-measuring device
called an anemometer. But this takes some serious time
and dedication. Or you can look at the attached map
to estimate the wind power productivity of your location.
Because wind speed increases with altitude, you’ll
want to get your wind generator as high off the ground
as possible. Trees and buildings also interfere with
wind flow so you'll need to keep the wind generator
at least 500 feet away from any of these types of obstructions.
As a rule, a generator mounted on a tower should be
20-30 feet higher than any surrounding trees.
The U.S. Department of Energy has an excellent consumer’s
guide to Small Wind Electric Systems. It will tell you
all you need to know about evaluating your site, determining
the size of the system you'll need, and much more. Be
sure to look at the state-by-state guide to regulations
and incentives for wind power in your state.
Wind Power Costs
The cost of a wind power system depends on how much
power you wish to generate. If you want to supplement
your existing grid-based power, or supplement a solar
system, you can get a small system that will run between
$5,000-10,000. If you want to install a larger system
that will cover most of your power needs, the system
will cost between $20,000-40,000.
Many states offer rebate or tax credit programs to encourage
the uptake of small wind energy systems. Depending on
the size of the system you buy, the amount of power
you use, and any tax or other incentives you may qualify
for, your payback period should be 5-15 years. Like
solar, wind power is a long-term green investment.
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