Solar Power Shingles: Bright Idea or Bad Investment?
To illustrate this point, let's take a look at an actual solar shingled roof installed on a
1200 sq. ft. home in Ann Arbor, Michigan.
Here's a breakdown of the components and the cost for each:
84 Uni-Solar SHR-17 solar shingles: $8685. One shingle is 84" long with 12-7"
tabs that resemble individual shingles. The total output of this system is 1428
watts. (84 shingles x 17 watts)
Outback FX2548 Inverter, 49-volt DC to 120-volt AC, 2500 watt $1640
" FXA Adapter Kit: $109.65
" PS2MP mounting plate: $103.20
" HUB-4 Communications Manager: $165.75
" RTS Remote Temperature Sensor: $24.65
" MX60 Maximum Power Point Tracking Charge Controller: $499
" PS2AC-50D AC disconnect box: $305
" PS2DC-100 DC disconnect box: $260
" Mate Remote Monitor and Control: $235
Shipping for above items: $149.17
Total cost for solar specific hardware: $12176.42
In addition to the solar specific hardware, the system uses 8 - 530 amp, 6 volt
batteries at $232 each for an additional $1856 plus shipping. By the way, these
batteries are shipped "wet" and weigh 127 pounds each.
The investment so far is hovering around $14,000 before the cost of installation.
Assuming you're an experienced do-it-your-selfer, you could probably lay the shingles
and wire them together. But the services of a licensed electrician would be required to
interconnect all the components and make the final connection. If you could get this
done for $1,000 - $1,500 it would be a gift.
The installation cost now brings the grand total to somewhere around $15,000.
Let's see how much supplemental power and what the resulting cost savings are from
$15,000 invested in solar shingles.
According to the homeowner, the average output from the solar shingle system is 4.7
kWh (kilowatt hours) per day, or 1715 kWh annually. The rate charged for electricity in
Ann Arbor, Michigan is $0.11 per kWh. If we multiply $0.11 per kWh x 1715, the result
is annual savings of $189.00.
If you add the value of future electric rate increases to the annual savings, the system
will return $2,400 worth of electricity over 20 years. This represents a negative 600%
return on the $15,000 invested. After you factor in the maximum $2,000 Federal Tax
Credit, the return improves(?) somewhat to a negative 550%.
To put it another way - over the course of 20 years, the homeowner ended up paying
5 1/2 times more for electricity than a similar house in his neighborhood without solar
It's unfortunate that this home owner's enthusiasm wasn't matched by a similar
commitment from the State of Michigan. As of this writing, the State of Michigan offers
no incentives or rebates for residential alternative energy upgrades.
Michigan solar power rebates are now handled through the major energy company
WPPI Energy, which also services the states of Wisconsin and Iowa.
Installations on pre-existing buildings undertaken by a non-certified installer, as was
the case here, would have qualified the homeowner for a $2/kWh rebate, or $3,430.
This amount would have been in addition to the 30% IRS tax credit of approximately
$4,500 for a total of $7,930; reducing the net cost to $7,070.
Qualified renewable energy home improvements are now also exempt from additional
local property tax assessments.
There's no shortage of praise
for Unisolar's new solar power
shingle technology, especially
from their own web site.
"Unisolar shingles are unique
and have been honored with
the prestigious Popular Science
Grand Award, Best of What’s
New, and Discover Magazine’s
Technological Innovation Award
for best innovation."
It's hard to argue with Popular
Science, but exceptional
technology doesn't always
guarantee an exceptional
return on your investment.