PV standardization

[magoo2]

Is there any effort in the industry to standardize the PV panels? I was looking at some commercial rooftop applications involving 1 MW and 1/2 MW designs. I find that contractors will select their own favorite vendors for the panels or find a deal on some panels and wind up with something not quite the same as his competition. I'm guessing this is due to the fact that the panel ratings aren't standardized. Is there any truth to this? It seems like each designer is reinventing the wheel.

With several projects in mind, will you be able to find one type of replacement panels that will be suitable replacements for a number of different suppliers?

My interest is more in the fixed pitched ballasted design but I think the question can be applied more generally.

 

[jfpe]

I don't think there will be standardization anytime soon. All of the module manufacturers are making constant, incremental improvements. A module foot print that produced 220W last year will produce 230W this year. This improvement is necessary to keep up with the competition. It is also advantageous, since the modules are priced by the Watt.

That said, many manufacturers have standardized on 60 cell modules. The voltage, current, and thermal characteristics are comparable between manufacturers.

-John

 

[Sparweb]

Some "standard" factors seen on the datasheets: power produced at 1000W/sq.meter, power produced at "normal operating cell temperature" and 800 W/sq.meter, current-vs-voltage curves, Isc, Vo, Vmp, thermal gradient for current and Vo...

But that's as good as it will get. What I learned of the way the panels are made at the factory (this is the Discovery channel version) is that they are tested, seemingly 100% of them, then sorted by performance. That's how you can have a datasheet with 6 models of panel on it, all the same size and apparent construction, but with a range of ratings from 200W to 250W. It's just a statistical spread of test results that show that some are better than others and the ratings are stamped on the panel according to the test.

There may come a time when supply of solar panels becomes a "commodity" instead of a "specialty product". The only thing I can think of that would transform the solar panel industry that profoundly would be if the entire US military decided to power all its bases from solar power and wrote a procurement specification with the size, construction and power defined in specific bands and tolerances. I think that is unlikely, but stranger things have happened.

My suggestion, with this kind of scatter in the data, is to design a large array in segments that can be swapped for different manufacturers when the need arises. A string of 8 panels may suffer damage to one, and it's a big problem if you can't get an identical replacement for that broken one. Even if the specs of a replacemnt can be matched, the chance that the panel is a different size and color will make a big difference to the curb appeal of the installation, and you customer will not be happy. But if the specs of the panel string are well documented, they can deal with the situation 10, 20 years from now by replacing the string with panels that will perform "close enough" to the original string so as to not affect the other strings.

What to do with the remaining 7? That's what e-bay is for. (Sorry, that is more humour than a serious cost-recovery option).



Steven Fahey, CET