Skewed results swipe SunPower X top result

Three Chinese solar panel modules (Sopray Energy, Risen Energy, and ET Solar Industry) took first, second, and third places in Photon Laboratory’s latest yield test – but the results are skewed. The solar panel Photon Lab says should have won is from the SunPower X-series.

As Photon Laboratory writes:

This year’s top three winners in PHOTON Lab’s annual outdoor module yield test – Sopray Energy, Risen Energy and ET Solar Industry – can count themselves lucky. Had it not been for our newly-developed testing equipment for IV curves that was still going through its growing pains, this year’s results, as last year, would quite likely have given a gold, silver and bronze sweep for one US company – SunPower Corp.

Because of the problems Photon Laboratory had with the device, measurements from 26 modules from 23 companies were deemed inaccurate. Ouch. Photon Laboratory’s only choice was to remove them from the 2013 test results.

Top 10 – Photon Lab’s 2013 yield measurements

• Sopray Energy: SR–190
• Risen Energy: SYP190S-M
• ET Solar Industry: ET-M66250WW
• Hanwha Q-Cells: Q.PRO-G2 235
• Sonalis: SL190TU–36M
• Risen Energy: SYP250M
• CSG PVTech: CSG240M2
• Renesola: JC245M–24/Bbv
• Sopray Energy: SR–156P–235
• CSG PVTech: CSG250S2

All modules in the top ten results produced similar numbers with regards to performance ratio – with only a single percentage point between the number 1 and number 10 spot.

None of the modules in the test field were cleaned of dirt or snow, and the test ran (for the first time) an entire calendar year. It will be interesting to see what happens next year, now that Photon Laboratory has its equipment functioning properly. Photon Laboratory is located in Aachen, Germany where it maintains the world’s largest outdoor test field.

As Photon Laboratory points out on their site, performance ratio defines the technical quality of a solar module, but other qualities also need consideration. The laboratory includes older installed modules in their findings, as well as models no longer manufactured:

Long-term stability is equally significant for a product that needs to function well for at least 20 years. Our tests are not designed to cover this, which arguably puts the older installed modules at a disadvantage in head-to-head competition. Indeed, the bottom three spots went to Photowatt International’s PW 1650–175W, installed in 2006, with an 80.6 percent performance ratio; Sharp Corp.’s NT-R5E3E, installed in 2005, with a 79.8 percent performance ratio; and Evergreen Solar’s ES–180-RL, installed in 2007, with a 76.6 performance ratio. Still, not all the older modules installed in the test field have shown their age. Siliken’s SLK60P6L 230Wp, installed in 2009, which in the 2011 yield survey was ranked number two (see PI/2012, p. 92), had only dropped to 15th place for this survey.

SunPower X-series: a clear performance winner

As far as performance rating is concerned, Sopray Energy’s SR–190 module returned a 94% rating in the 2013 report. The number 10 panel performed at 93%. Where would SunPower have placed? We can’t know for sure, but in the 2012 report, the leading SunPower X SPR–327NE-WHT-D performed at 95.2%. The second and third place modules, also manufactured by SunPower, returned performance ratio values of 94.9% and 94.8%.

We’re eager to see the results next year and in the years to come. Everyone we know who owns the SunPower X-series gives them terrific reviews: they’re said to produce up to 75% more energy over the first 25 years compared to other solar panels, they look great, and their efficiency, power density and 25 year warranty are hard to beat.

See more:

SunPower X-series Solar Panels (at us.sunpower.com)
Photon Lab’s 2013 yield test results (pdf, 258 kb)