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Communications Case Study: A PV-Powered Telephone Signal Booster in Nevada

The place: a remote signal station in the mountains of northern Nevada. The situation: Sprint Communications decides to reduce the amount of time the company runs its propane-powered electric generators by adding PV modules.

When Sprint Communications built its east-west fiber-optic cable line in the late 1980s, it needed a regenerator station every 22 miles (35 kilometers) to boost the signal. These regenerator stations use electricity 24 hours a day, 7 days a week, to power the transmission equipment and control shelter temperatures. Utility power serves most of the stations, which have 2 hours of backup battery capacity should the power line go down.

But at Sand Pass, Nevada, bringing in utility power was prohibitively expensive. When Sprint built a regenerator station there in 1986, it installed two propane-powered electric generators. But to maintain the generators, a mechanic had to drive out to the pass every month, and to provide fuel, a teamster hauled a heavy propane tank over rough dirt roads to the site every 3 months.

The solution was to install a PV system at the Sand Pass station. The PV array and propane generators at Sand Pass complement each other well. The PV array charges batteries that power the dc transmission equipment. The generators are used to power the ac motor in the air-conditioning unit only when the shelter thermostat calls for air conditioning. As added backup, the generators can charge the batteries, if necessary. Because relieving the generators of their everyday battery-charging duties has reduced the amount of time they run, the PV system has significantly lowered the station's fuel and maintenance costs.

For additional PV case studies, see: