Solar panels after 25 years: Is there an afterlife?

Price drops in recent years have made the idea of investing in PV extremely attractive, with or without subsidies. In well-designed and well-utilised systems, the investment pays itself off in a number of years and long before the standard warranty period is over. But what happens after that? Should systems be simply discarded and replaced? Or perhaps recycled? There may be ways to further capitalise on the investment. This post will explore other options available to PV investors when their warranty period expires.

Top tier manufacturers are now commonly offering a 20–25 year performance warranty, ensuring that consumers will receive panels which perform at a minimum of 80% of their nominal capacity at the end of the warranty period. Although a 20% drop is a sizable decrease in performance, systems operating at 80% of their original capacity can still contribute a significant amount of electricity. The system may continue to operate in that state as-is or with minor additions, depending on site requirements (e.g. a standalone system vs. one that exports to grid).

In addition, those close to the PV industry have come across examples and anecdotes which suggest that a number of PV panels have lasted well past their design life. In the mid-1970s, Telecom (now Telstra) deployed a network of PV-powered repeater stations to provide phone access to some of the most remote parts of outback Australia – some have claimed that many of these repeater station panels outlasted their warranty period and are even operational to this day. Think of all the old antique cars, appliances and homewares which are still being used today. If cared for properly, items can last for many decades. This is also true for PV panels.

So what does this mean for investors? The fact that there is a good chance that PV modules will perform reasonably well beyond their warranty period means that the overall return on investment will be greater over the actual lifetime – not just the warranty period – of the PV panels. It is also another reason to choose high quality modules with more reputable brands which are likely to stand the test of time.

This can also mean that PV panels can hold a resale value at the end of the warranty period. A simple Google or eBay search for second hand PV panels reveals the demand for such goods. There is a market out there for people willing to buy and sell used PV panels, much like there is a market for the sale and purchase of other electrical equipment. It may be possible to recoup a small portion of the initial purchase price in this manner.

However, one potentially difficult issue surrounding the sale of used PV panels is in determining appropriate pricing. The principals of the ‘bathtub curve’ for reliability suggests that the relationship between the price of second hand panels and their use life should not be linear – much heavier discounting must be applied towards the end of the warranty period to account for cumulative wear and tear and an increased probability of failures.

The length of standard performance warranties for PV modules have steadily increased over the past decades and we are continually learning about the behaviour of state-of-the-art PV modules in the field. Twenty years ago, the cumulative installed capacity of PV worldwide was a meagre 192 MW and we will have to wait a little over a decade until we see the gigawatts of installed capacity this century reach the end of their warranties. Regardless, early signs are showing that there is indeed hope of an extended system life after ‘death’.

Top Image Credit: Process Industry Forum

© 2015 Solar Choice Pty Ltd

John Rodriguez

John regularly contributes original technology articles to Solar Choice News. He is a PhD candidate in solar PV engineering at the University of New South Wales (UNSW), having graduated with First Class Honours in a Bachelor of Engineering (UNSW, specialising in PV). His knowledge of and passion for renewables technology led to him receiving the federally-funded Australian Postgraduate Award and Engineering Research Award for research excellence, in addition to being a Co-operative Program scholar during his undergraduate studies. John also works as an energy efficiency and process engineer and analyst.
John Rodriguez

Comments

  1. I think what everyone fails to address every time this subject surfaces is that as technology progresses electrical devices become more efficient so even though the panels appear to degrade/break-in to about 87% of their original rating they still provide the “same” saving 30 years later… pound for pound that is!
    i.e. incandescent to LED’s etcetera.

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