The New Mexico Solar Tour: Part 1 - Panel Degridation Cannot Lie, So Plan Smart

Pam Cargill at SWRES

Pam Cargill at SWRES

Today and tomorrow I am on a PV tour-de-force of New Mexico. Today, I am visiting the New Mexico State University's Southwest Technology Development Institute (SWDTI). SWTDI operates the Southwest Region Experiment Station (SWRES) for photovoltaic systems located on the campus of New Mexico State University in Las Cruces, NM.

Staff at the SWRES include National Electric Code Section 690 expert John Wiles, who is probably best known in the DIY solar space for his contributions to Home Power Magazine's Code Corner, from which I remember eagerly reading his contributions every issue when I first became interested in solar energy back in the late 1990's.  It's been a pleasure to finally meet John and tour the facility, which is host to a dozen acres of experimental solar panel, racking, and inverter testing on the roofs of several buildings and surrounding ground area.

Degraded cells on a PV panel

Degraded cells on a PV panel

There are some 20-year-old panels out on the property from the likes of Arco (now SolarWorld) and Solarex (now BP Solar) and some quite worse for the wear. Delamination, uneven degradation of cells, backsheet slumping, and junction box failures are visible in many of the experimental installations. Almost all of the module manufacturers represented in the field here have been out of business for more than 20 years. This, of course, is very disheartening, especially as developers roll out large-scale solar PV installations worldwide composed of solar panels manufactured by companies that have barely been in business for five years.

The industry standard power performance guarantee is 20 years (some boast 25 years) and many top manufacturers offer at least 10 year warranties on defective product. Considering how many manufacturers are entering the marketplace every year and how many have historically exited the marketplace within a five-year period, this leaves the design and engineering teams with integrators in a precarious position when specifying product for installations that they themselves are standing behind for at least 5 and sometimes even 10 years.

This becomes even more critical for the large commercial and utility-scale industry riding heavily on Power Purchase Agreements (PPAs), financial agreements based on the ability for a system to produce power at a specific uptime and maintenance schedule in order to stay profitable for the financier. Major product warranty issues can put the success of a PPA in jeopardy if it affects system uptime, which affects whether or not a PPA servicer can bill a client for energy produced by the system and starts a cascade of costs that can adversely affect the ROI of a PPA system.

So what does this all mean?

Some Delaminated and/or broken PV Modules

Some Delaminated and/or broken PV Modules

Integrators should work closely with experienced solar energy engineers and industry product procurement professionals to assess and select the most robust and appropriate equipment for their design needs. Look beyond the spec sheets and marketing materials of module, inverter, and racking manufacturers to their independently verified listings, product tests, and any independent field testing and results that exist. For example, Photon International puts out a comparison every year of the latest module offerings from top manufacturers and tests how they stand up in real world conditions to the specs on their data sheets. For the sake of our industry as a whole, it is important that we all strive together to employ best practices and smart planning in the design, execution, and maintenance of solar electric systems in order to continue to prove and prove again the solar energy is a stable and viable technology that will be a serious player in the energy solution to the climate change problem.