Weighing all of these factors can be a time-consuming process that inevitably ends up in compromise. And each system designer or homeowner will have to establish their own priorities.
This will be the third PV array our family has installed, and cost, while important, is no longer at the top of the list. With our two previous homes, low module cost was the highest priority, and I simply jumped on “deals.” The first array used Astropower modules, which are no longer under warranty since the manufacturer is long gone. The second array contained a few underperforming modules (see “Potential PV Problems” in HP143). While both arrays are still pumping out energy, I have learned to consider more than just cost. Unfortunately, there is no long-term module quality specification, so it is difficult to know if a module is and will continue to be a top performer—manufacturers are not required to publish module failure test data.
As the PV industry matures and module-level monitoring becomes more common, we’ll likely have more data on how specific modules perform over the long term. Pressure from within the industry (such as larger system integrators and project developers) also may help remedy this situation. It is an unfortunate reality, but not a reason to keep me from investing in my next array. Will my next array perform as expected five or 10 years from now? I don’t know. Will the manufacturer I buy from be around to honor a warranty claim? That’s an uncertainty, too.
What I do know is that my last two arrays are still working—in spite of a defunct module manufacturer and a few underperforming modules. And with that confidence in basic PV technology, I will optimistically move forward with my next solar adventure.
Justine Sanchez is a Home Power technical editor and an instructor for Solar Energy International. She is certified by ISPQ as a PV Affiliated Master Trainer. Justine is hoping to close on her new family home soon, so she can start ordering the equipment to make her next dream PV system a reality.