Carter Era Solar Panel Performance Amazes Owner

A story in Green building advisor sheds some light on how long the solar panels on your roof just might keep on pumping out power.

While most appliances only use energy, rather than make energy, and are not subject to the rigorous second-guessing of solar arrays (when was the last time you demanded a payback analysis on your car, your fridge or your giant plasma TV?) a solar array is just an appliance that supplies a personal power supply, after all. Like a car, a fridge, or a plasma TV, it provides you with a service.

So, will it outlast your car, fridge and plasma TV? Apparently: yes.

Green Building Advisor’s Green Building’s Martin Holladay tested the 30 year old solar panel that he originally purchased and installed in 1980. To mark the 30th anniversary, Holladay climbed on his roof and brought one of his panels down for testing. He was curious to see exactly how well it was working, compared with its original rating.

He connected it directly (with no intervening battery) to two different 12-volt loads to test it: a 35-watt incandescent light bulb, and a blower rated at 4.5 amps (about 54 watts). Result? “The old PV module passed with flying colors. It easily powered up the light bulb; my Fluke multimeter showed that under a full load of 2.015 amps, the module’s voltage was an impressive 14.93 volts” said Holladay.

The panel tested at an even better performance than when the panel was new. Read more…

“The next test was more challenging”, says Holladay. “I hooked up the 54-watt blower directly to the panel. Wow! The blower started spinning at a fast clip. According to the Fluke multimeter, the blower was drawing 2.5 amps from my ancient solar panel — more power than would be expected from the factory specs”.

Most solar warranties are predicated on the idea that panels will typically lose a half percent a year in performance. That is why most solar panel warranties are for 25 years. At that point the panel is (theoretically) on average, going to be producing 12.5% less.

His was an Arco Solar Panel, Model 16-2000, that had been made in California when Carter era subsidies began the solar industry. The Arco factory’s new owner expects a little less degradation than that average annually, but he was astounded by the results. There was no change from the original specs.

“Your module is still performing to factory specifications — or perhaps a little better” said Raju Yenamandra, the North American head of sales and marketing for SolarWorld. “That’s very good. We usually tell people to anticipate a performance degradation of 0.27% per year.”

Arco sold its solar division to Germany’s Siemens in 1989, saying it wanted to return to its core business, oil. The original solar industry left the US when Republicans once again defunded the nascent renewable industry, and it was picked up by Germany and Japan.

Germany’s Siemens is now a world leader in both solar and wind, and just beat out GE to make the world-class giant turbines needed for the first off-shore wind project in the US. In 2006, on the cusp of California’s rebirth as a solar power with its AB32 climate and clean energy law imminent, Germany’sSolarWorld bought out Siemens’ old Arco solar panel manufacturing plant in California.

Image: GreenBuildingAdvisor

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