Fantasy Solar Cabin

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The fantasy solar cabin became a reality in 1990. Selway Lodge's solar array can see it through 10 sunless days.

Over the past 93 years the Selway Lodge has gone through several transformations. Built in 1898, the lodge was the centerpiece of a 100-acre cattle ranch and sawmill deep in Idaho’s Bitterroot wilderness area, reachable only by fourteen miles of trail or a rather exciting bush plane ride. By the 1920s, the many cabins scattered around the property (regularly visited by bear, cougar, elk, and deer) served as a summer hunting and fishing retreat. Though the property shrank in size when a good chunk was sold off to the Forest Service, the housing complex expanded: Two houses, a dorm, and several outbuildings were added to accommodate the growing number of visiting outdoor enthusiasts.

Despite the growth, the lodge continued to rely on a primitive hodgepodge for its energy needs: gas generators: kerosene lamps: and propane-powered refrigerators and stoves, the fuel for which had to be flown in regularly at great expense and danger.

Last summer, the Selway Lodge initiated a solar cabin project to enter the 21st century. Owner Pat Millington sprang for a $22.000 solar array (including a couple of Sunfrost refrigerator/freezers) to provide all of the lodge’s (minus the two houses’) energy needs. The entire package was installed over the course of a couple of days by Sunelco, an alternalive-energy company located in Hamilton. Montana.

The project got a running start before it even got off the ground: Several weeks of preparation and pre-assembly assured success before some seven plane loads of equipment took off into the wilderness. The Millington’s chose a system using Solarex 60-watt solar modules. These modules (what we see as “panes” of solar-activated material) were mounted on Solarex mounting structures. Four six-module structures were then bolted together with a set of top and bottom plates.

Soon the arrangement was moved into place and bolted securely to the building’s rafters. The array was divided into two subarrays, each with its own individual charge controller–important for preventing overcharge of the batteries. Two fused disconnects (fused on/off switches) provided complete flexibility and safety–both the array power and battery power can he individually disconnected.

Sixteen batteries (350 amp-hour fork-lift type) were employed–four in a series to yield 24 volts with four sets in parallel to yield 1400 amp-hours of storage–but because of the distance involved between the cabins and the battery bank, all of the loads were designed to operate on 120 volts AC

Necessity and convenience were factors in the decision to add two inverters, which convert DC electricity to 120 VAC electricity. First, the Lodge demanded maximum reliability. If one unit were to fail, the lodge could be run off one inverter. Second, the Lodge boasts some 30 light fixtures as well as refrigerators, kitchen appliances, and a washer and dryer–so it became necessary to separate the loads. One inverter was chosen to handle the lighting while the other took on the heavier power users. The benefit? None of the lights dimmed when a large motor started. Though separating the loads in this way is not crucial, Pat found this a good solution to the constant “browning” of the Lodge.

With no moving parts, and a maintenance schedule that only requires watering the batteries three times a year, the Selway’s system is stunningly simple. Perhaps its greatest asset is its cost-effectiveness. Pat expects to recoup her investment in five to six years; after that, the Selway Lodge array rides for free. The batteries are expected to last 10 to 15 years, the solar panels at least 30.

But the solar solution provided more than just economic relief. During the three month summer season, about 30 bottles of propane had to be flown in. And in case of an accident, needless to say, the Millington’s would have been their own fire department. “Between the fumes and the spills,” says Pat, “I’m surprised the lodge has stood for as long as it has.” Pat also got the chance to replace two older gas refrigerators with two 19 cubic-foot refrigerator/freezer units. This again reduced the propane consumption and greatly expanded food-storage space.

Now with lighting in the main lodge, dinner time is a much more, well, enlightening experience. Admits Pat: “I do miss dining by those kerosene lamps, and the old conversation our walls have heard many times before.”

Just a few years ago, solar power made sense only for remote hideaways, and then only if buttressed by a backup system. “Today,” says Dan Brandborg, owner and president of Sunelco, “photovoltaics can provide up to 90% of the annual energy needs of a house almost anywhere in the country.” And since photovoltaics are quickly becoming an economical source of electricity for the power companies, why not beat them to the punch?