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SINCE
1987
WIND
Our 2009
GUIDE
What to Know
Before You Buy
Essential Sizing & Selection Advice
Capture Up to 40% More Energy
Jun / Jul 09, Issue 131
A Buyer’s Guide to High-Efficiency Tanks
contents
June & July 2009
38
buying
wind
Mick Sagrillo & Ian Woofenden
Two veterans in the small wind industry give the straight scoop on
selecting the right wind turbine for your site. Includes full specs on
22 turbines available in North America.
50
sun
trackers
Justine Sanchez
In certain situations, tracked PV systems can offer a performance
advantage. Here’s how to determine if a tracker is right for your
situation.
60
bayou
solar
Kelly Davidson
In the aftermath of Hurricanes Katrina and Rita, generous incentives
helped these homeowners become more self-sufficient—and ready for
the next storm.
6
home power 131
/ june & july 2009
On the Cover
Aspen Crouter and Jake Kollmar
of Highland Energy Systems
work on a Proven 6 kW turbine,
175 feet above the ground.
Regulars
Home Power
crew
Doing it yourself
Photo by Arlene Smith
Domestic
Water Out:
Hot
Domestic
Water In:
Cold
12
The Circuit
Home Power
contributors
News, notes & gear
Backup
Electric
Element:
With
thermostat
24
Mailbox
Home Power
readers
Feedback forum
Industry professionals
Renewable energy Q & A
Solar Heat
Exchanger
In:
From
collector
Solar Heat
Exchanger
Out:
To collector
John Wiles
Array to inverter
70
SHW
storage
Brian Mehalic
Heat exchangers? Backup elements? Tank lining? Sacrificial anodes?
How to choose the right storage tank for your solar hot water system.
Michael Welch
Capping & trading
Kathleen
Jarschke-Schultze
Free markets
82
solar
economics
Dan Chiras & John Richter
Satisfy your inner bean-counter, and learn methods for analyzing
whether your solar-electric system is a smart investment.
118
RE Happenings
120
Marketplace
88
ireighter
safety
Matthew Paiss
Could the PV modules on your roof hinder firefighters’ effectiveness—
or even endanger them—in an emergency? A San Jose, California, fire
engineer deals with the myths and the facts.
122
Installers Directory
Erika Weliczko
PV IV curve
96
backup
generators
Allan Sindelar
Enough isn’t always enough—sometimes a backup generator is a
necessity. Here’s how to pick the right one for your needs.
Home Power
(ISSN 1050-2416) is published bimonthly
from offices in Phoenix, OR 97535. Periodicals postage
paid at Ashland, OR, and at additional mailing
offices. POSTMASTER: Send address corrections to
Home Power, PO Box 520, Ashland, OR 97520.
7
7
Yourself
We’ve been receiving a stream of questions from
Home Power
readers about books en-
couraging do-it-yourselfers to build their own solar-electric modules—some promise
a functional system for a few hundred bucks. For the record,
forget about it
. Building a
solar-electric module is a great science project, but the reality of the project stops there.
This thread did get me thinking about where DIYers stand in today’s renewable
energy landscape. Over the past 20-plus years, we’ve seen hands-on readers design
and install small systems that rival the workmanship of seasoned pros. We’ve also
seen our share of owner-installed systems that fall under the “disaster” category.
Poor design work will cripple a solar-electric system’s energy harvest over its entire
lifetime—25 years or more—and undermine the return on your inancial invest-
ment. While bad design impacts energy production, bad installations can result in
damaged equipment, ires, property damage, injury, and death.
So before undertaking a hands-on solar-electric project, take some time to think
about the following:
Consider the project.
A small, low-voltage off-grid system is a completely different
animal than a residential-scale grid-tied system, which can produce voltages as high
as 600 VDC. Homeowners should not undertake the latter unless they have experi-
ence working with high-voltage electricity.
Assess your design knowledge.
Blowing a system design can be as simple as one
miscalculation or one poorly selected component. Doing your homework and seek-
ing out design advice is the irst step in building a system that will not only work,
but work
well
.
Be realistic about your installation skills.
Unless you have experience working with
electricity, knowledge of the
National Electrical Code
, and the correct tools and protec-
tive equipment to perform the installation safely, hire a licensed solar-electric installer.
Determine your goals.
If you’re looking to save a few bucks by installing a system
yourself, here’s a reality check: Depending on where you live and the complexity of
the system, installation costs for a residential system may range from 10% to 20% of
the total system’s cost. You’ll need to weigh whether the savings are worth it, and
determine if homeowner-installed systems qualify for rebates that may be available
in your area.
Most do-it-yourselfers have one thing in common—they get excited about a project
for the project’s sake. They tackle it because they enjoy the learning experience
and doing the work with their own hands. But experienced do-it-yourselfers have
learned, sometimes the hard way, which projects are doable and which ones are not.
This awareness is one of the most useful tools you can carry when you’re consider-
ing a home-scale RE installation.
—Joe Schwartz for the
Home Power
crew
Think About It...
“If your project doesn’t work, look for the part
that you didn’t think was important.”
—Arthur Bloch, author of (you guessed it) the
Murphy’s Law
books
home power 131
/ june & july 2009
from us
to you
Doing It
the circuit
news
nOTes
GeAR
solar savings by the numbers
Rather than paying more money to buy the same items
separately at our local supermarkets, my friends and I often
buy in bulk from wholesale warehouse clubs—we share
the membership fee, we share the cost, and we all share the
savings. It’s our very own bulk-buying cooperative.
That’s essentially the idea behind One Block Off the Grid
(1BOG), a San Francisco-based organization promoting solar
energy through old-fashioned community organizing and
group discounts.
By banding people together in different cities, negotiating
on their behalf, and buying in bulk, 1BOG is helping
homeowners get discounts on solar-electric systems—up to
20%. The goal is to increase the adoption rate of solar energy
by taking the fear out of the buying process.
By banding people together in different cities, negotiating
on their behalf, and buying in bulk, 1BOG is helping
homeowners get discounts on solar-electric systems—
up to 20%.
Courtesy www.1bog.org
attending renewable energy fairs to generate interest in their
“group purchase” concept.
Their grassroots efforts proved fruitful: 180 homeowners
signed up; 80 followed through with professional site surveys
arranged by 1BOG; and of those, 42 installed PV systems on
their homes—all at a discount of 20%, thanks to 1BOG’s bulk-
buying muscle.
“For someone who is unfamiliar with the technology, the
buying process can be daunting,” says Dave Lorens, general
manager and cofounder of 1BOG. “It’s difficult to know
which installer to trust and whether prices are fair. We try to
fix these problems and eliminate the trust barrier.”
The startup is the brainchild of Dan Barahona and Sylvia
Ventura. In 2007, the couple began exploring the idea of a
solar-electric system for their San Francisco home. Even with
backgrounds in electrical engineering and biotechnology, the
couple found the buying process to be overly complicated by
jargon, technical concepts, and government regulations.
They took matters into their own hands, researching the
ins and outs of solar over several months. In the end, they
installed a 2.5 kW PV system on their home and found the
inspiration to create 1BOG.
The couple partnered with Lorens, then a salesperson
who worked for their installer, and shared their ideas for
streamlining the buying process. Working from a coffee shop,
the trio hatched the concept for the 1BOG initiative. (See
“Behind 1BOG” sidebar.)
In May 2008, 1BOG ran its pilot campaign in San Francisco,
with a small team of staffers and volunteers going door to
door, stopping people on the streets, sending out e-mails, and
Behind 1BOG
1BOG capitalizes on the fact that there is power in
numbers. Signup is free, and once 100 homeowners
in a city or town are on board, 1BOG begins the
proposal process and acts as a representative for
the homeowners—negotiating with and selecting
installers. Homeowners schedule evaluations with the
installers and decide whether to follow through with
an installation. There is no obligation to buy. 1BOG
generates revenue through a referral fee from each
selected vendor participating in 1BOG programs—
roughly 25 cents per installed watt, while installers save
money on sales and marketing costs.
12
home power 131
/ june & july 2009
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