30-Year-Old Solar Module Performing to Factory Specs

Tom Jackson
October 26, 2012 | 8 Comments

Martin Halloway, a green building designer, had been living without electricity for five years before he purchased his first solar panel in 1980. This exact module, an Arco Solar 16-2000, 33 Watt solar panel, was manufactured in 1979.

In 2010, Halloway decided to bring the solar panel down from his roof after 30 years to test it out. It was an oddly crisp, clear day of about 50 degrees Fahrenheit.

Halloway's solar panel was designed for a 12-Volt battery (Max. Voltage of 16VDC), so he tested the module by connecting it directly to 12-Volt loads.

Halloway's first test was connecting a 35 Watt, 12 Volt incandescent light bulb. The light bulb lit up, passing test number one. Halloway says that his Fluke digital service multimeter showed that with 2.015 amps, the voltage of the module at 14.93 Volts.

Next, Halloway connected the Arco Solar Panel to a 4.5 amp, 12 Volt blower. The blower drew 2.5 amps from the thirty-year-old module, which is higher than you'd imagine based on the module's factory specifications. Remember, this is a 33W panel that was purchased in 1980.

When Halloway called up the manufacturer to share the exciting news, they were surprised but explained how this was probably due to the cool weather during this test. The cooler temperature must have given the panel a 10% increase in performance.

Warranties generally cover a solar module for up to 25 years at 80% nominal output. Over the years, all solar panels will degrade somewhat, but crystalline silicon panels have a much slower rate of degradation than thin film. To be considered effective by most manufacturers, a solar panel has to operate at least 80% of its rated peak output. So even when some older modules may not reach that 80% mark of the rated peak output, they can continue to produce smaller amounts of energy for years after their warranties are up.

This Arco solar panel, however, far outlived its warranty and is certainly working well into its old age.

With the improvements to solar panels since 1979, how long into the future could some of today's solar panels be working?

Image Credits: www.greenbuildingadvisor.com/

The information and views expressed in this blog post are solely those of the author and not necessarily those of RenewableEnergyWorld.com or the companies that advertise on this Web site and other publications. This blog was posted directly by the author and was not reviewed for accuracy, spelling or grammar.

8 Comments

Peter Bradshaw
November 1, 2012

The article about how silicon ICs turned to Melba Toast after (as I recall) 14 years was a joke, published on April Fool's day many years ago. There is no basic reason the silicon photo-voltaic cells themselves will degrade over any plausible time. The very fastest IC technologies have finally, a couple of years ago, reached electronic stress levels where some degradation can be expected over time, but the stress levels in PV cells are so much lower, they should last 100s or even 1000s of years. The only likely degradation would be in the transparent cover, and corrosion in the external interconnects. Thus if these are taken care of, the solar panels should last for a very long time. Even if these are not taken adequate care of, the cells, which form a large fraction of the cost of the panels, could still be retrieved and re-used in new panels, with the same performance as the original panels. Of course, by then newer panels with improved performance might still be a better bet.

ANONYMOUS
October 30, 2012

Maury: Why do you feel the need to criticize the article? Do you have nothing better to do than trolling sites that are trying to get useful, factual information to readers? There is no reason to attempt to discredit the author for sharing a great story just because it was shared back in 2010. Your assertions that this was posted so that someone could get paid are conspiratorial and ridiculous. You are basically implying that this great resource for renewable energy news is a farce. You may as well stop reading REW if you're going to assume that their motivation for providing content is to pull the wool over your eyes to make a buck.

I and most of the other readers would not have known the article existed if it hadn't been "recycled". Furthermore REW didn't have to feature this blog post, but they did because the information is useful to those who are wondering just how long panels can last. There is a lot of confusion on this subject. I once had someone tell me they were convinced that after 6 years panels basically produce no power (he cited the fact that he was an LADWP employee as a reason that he would be an expert on this subject), and that just isn't true. So I highly encourage more bloggers to post interesting, relevant content, even if it has been posted elsewhere, just as long as there is no plagiarism happening. Truth is still truth, even after 2 years. :p

Tom Jackson
October 29, 2012

Kevin- Without sufficient empirical knowledge of panel degradation a few decades ago, manufacturers had to play it safe with shorter warranties. As many of these older panels showed such rate of degradation, they were able to confidently extend warranties to a couple decades. Most importantly, the long life of panels adds value for the customer... All good things!

Maury- I am the "writer" you are referring to in this instance ;) You are correct that Halloway posted his story a couple years ago, but the age of this information does not diminish the value for readers who have not had the chance to hear the story. That's why I wrote it. Thanks.

Maury Markowitz
October 28, 2012

This story is several years old. Why is it being recycled now? Does REW have nothing better to print today? Or do the "writers" get paid by the article? Here's the original from two years ago: http://www.greenbuildingadvisor.com/blogs/dept/musings/testing-thirty-year-old-photovoltaic-module

Kevin Meyerson
October 28, 2012

There is a company in Japan that purchases and resells used solar panels that have outlived the original buildings they were installed on decades ago. The vast majority of panels perform at or near factory specification. Thin panels are expected to last as long or longer than the older silicon panels. Most industry experts tell me that the panel coating processes are far superior than what they were three decades ago so all panels are expected to last even longer.

The solar industry needs to be more aggressive in marketing the long life of solar panels, IMHO. According to the industry experts here in Japan, panel manufacturers originally put shorter warranty periods on panels since they just did not know how long panels would last - they were making super conservative 'guesstimations.' As the reality of super long lasting panels makes itself known, the expected cost per kWh for solar installations should drop significantly as nearly all of the cost of solar is based on upfront costs divided by expected lifetime power generation.

Gary Richardson
October 27, 2012

Thinner panels equals potentially less time for corrosion to do its work. I'd be interested to see a vertical slice through one of these cells and view it under an electron microscope to see how much corrosion has penetrated the surface or if any erosion has happened elsewhere.

Alberto Valdes
October 27, 2012

That´s true! mine is a Siemens M50 bank installed in 1992 and still works at 92% of it´s initial regime.

Calvin Verdun
October 26, 2012

Martin great job of taking care of your panels!

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Tom Jackson

Hi folks. My name is Tom and I work for a company called GoGreenSolar.com, a leading online retailer for solar products, LED lights, etc. I blog about solar, green living, politics, and anything that strikes my fancy.