Solar Power Outside the Sunbelt

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PV power is clean, efficient, and has no moving parts.
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After reading by gas lamps and candles for 50 years, hut visitors are finally able to turn on the lights
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Originally mounted flush with the roof, the PV panels are now being retrofitted and mounted on poles to take advantage of the higher summer sun.

Think you have to live in New Mexico to get enough sun to
run all your lights and appliances with photovoltaic
panels? Maybe you live in Minnesota or Maine and can’t see
the sun from November to March. Or in British Columbia or
Alaska, where surely temperatures are too frigid to
efficiently upkeep solar panels. Well, you just might be
unfairly dismissing the solar option. It’s time you heard
about a new system of panels that operates year-round above
8,000 feet, in one of the coldest, stormiest stretches of
the Colorado Rockies. In winter, the panels withstand wind,
snow, ice, low light, and temperatures that drop to

The power system was designed for the 10th Mountain
Division Hut Association, which maintains a network of ski
huts–24 in all, 13 looped between Aspen and
Vail–that are linked together by cross-country ski
trails. A working experiment in solar for extreme weather
conditions, the 12-volt DC system has been upgraded several
times since it was installed in 1982. And as the
photovoltaic (PV) industry evolves, adding on to and
upgrading the system is becoming less and less expensive.

Built in the 1940s for the 10th Mountain Division of the
U.S. Army, the huts were initially used to train American
troops for mountain combat in the Alps during World War II.
Each hut sleeps between 16 and 20 people and is about the
size of an average family home. Originally, fuel lanterns
and candles lit the huts, but as the number of recreational
visitors increased, disposal of hundreds of lantern-sized
propane tanks became problematic for the not-for-profit
10th Mountain Division Hut Association. When one of the
huts burned in a fire started by a candle, the organization
made the decision to install new lights. PV was not an
obvious choice, given backcountry skiers’ interest in
preserving the pristine and rustic look of the remote but
system. The solar panel, though efficient, is certainly not
rustic-looking. But in the end, practicality won out over

Instructors Johnny Weiss and Ken Olson of Solar Energy
International (SEI), a nonprofit, renewable energy
education and training organization, designed a system for
the huts that is able to endure severe conditions, but is
otherwise not so different from any other solar power

“The only real difference is in the voltage,” says Scott
Ely of SunSense, a one-man solar installation company based
in Snowmass, Colorado, that has an ongoing maintenance
contract with the Hut Association. “When the cells are hot,
they lose voltage.” In other words, desert systems need
higher voltage panels than cold weather systems do.

The 10th Mountain system relies on one to six panels per
hut. Originally, the huts were for winter use only; so
SunSense, along with SEI students and instructors, mounted
panels flush with the side of the house. (SEI has kept its
students involved in the solar but project, using upgrades
and maintenance as teaching opportunities.)

The original panel installations worked well with snow
reflection and low winter sun. But now the huts have been
given U.S. Forest Service permits for summer use, and so
the panels are being retrofitted and mounted on poles to
accommodate the higher summer sun angle.

When it became apparent that the panels needed to be
retrofitted, 10th Mountain considered some other
alternative energy options, including wind mills. But
again, consideration for the quiet beauty of the area
brought them away from noisy wind generators and back to
quieter solar.

Batteries & Lights

The huts get the heaviest use during periods of least sun
and when the batteries, which are deep-cycle golf-cart
models, are the coldest. Most of the huts use lead-acid
batteries, though two systems use ni-cads and nickel irons.
The batteries are stored inside the huts or inside adjacent
storage rooms.

When 10th Mountain installed the lights, which are the only
appliances in the huts (heat comes from woodstoves), it
chose to place compact fluorescent lights in lanterns.
Interestingly, the compact fluorescents are now being
replaced with 12-volt incandescent low-wattage bulbs in
lanterns. Because of the high energy efficiency of the
compact fluorescent, this change may be seen in the
renewable energy community as a technological step
backward. Ely defends the decision, however, saying the
incandescents eliminate a ballast that comes with
low-wattage fluorescents. The fluorescents are also more
expensive in the short run and, despite what manufacturers
are touting as the new softer and dimmable fluorescent, the
fact remains that the quality of light is better with
incandescents. But most important for these circumstances,
claims Ely, the incandescents guarantee fewer cold-weather
start-up problems.

Cost & Maintenance

Ely estimates that the cost of complete solar installation
ranged from $5,000 to $8,000 per hut. Installing a similar
system on a home could be comparable. “We do this all the
time for remote homes,” Ely says. Installing this system on
a home, however, would require the addition of an inverter
to transform DC into AC for AC appliances (the mountain
huts use only DC). Ely says the cost of the inverter would
bump up the installation price by a few thousand dollars.

To maintain the system, SunSense visits the huts twice a
year to tighten connections, add water, and equalize
batteries. Occasional upgrades have involved moving battery
boxes around to better locations, installing summertime
panels, changing bulbs from compact fluorescents to
incandescents, and, most significantly, changing the power
centers. Ely says for safety reasons all the huts were
retrofitted with Anaconda power centers, which allow
everything-meters, breakers, etc.-to be centrally located
in one box. The cost, he adds, is less than $10 a year per
but to maintain the system (not including upgrades).

What this extreme experiment has shown, notes Weiss, is
that harsh conditions do not detract from the easy,
low-cost maintenance of solar. “There are no moving parts
in this technology,” he explains. “Nothing wears out. It’s
simply moving electrons.”

One of the benefits of the mountain huts’ power system is
that it has helped popularize the technology. Says Weiss,
“We’ve certainly seen it become very much mainstream. This
is not backwoods technology anymore; there’s no longer
anything experimental about it. It’s the same kind of
technology that people put on their homes and cabins.”
Weiss’s solar students use the system for hands-on
learning, and thousands of skiers visit the huts each year.

“The public has to turn the system on and off and [so they]
see the components,” notes Jarod Trow, head of operations
for the 10th Mountain Division Hut Association. “Underlying
this is the hope that people will take this experience back
home and [that it will] make them more energy conscious.”