Since there are no currently active contests, we have switched Climate CoLab to read-only mode.
Learn more at
Skip navigation

Community Discussions

Common Easy to Understand Measures of Solar PV efficiencies

Share conversation: Share via:

Eric Durbrow

Aug 22, 2011


1 |
Share via:
Recently, the EPA has redesigned car stickers that make it easier for consumers to shop for high efficiency vehicles. I think these stickers can work for both electric and hybrid and conventional vehicles. I read of "breakthroughs" in the solar PV industry almost daily. Often I see a percentage such as "34% efficient." Greater public attention would be generated by these "breakthroughs" if a better metric could be used such as $ per kilowatt hour generated or $5000 array will break-even in X number of months. I am wondering if (a) we could devise a more public friendly metric that would work across PV (and possibly the new PV-hydrogen) technologies and (b) if such a metric would generate more interest from consumers and venture capitalists.

Chris Horn

Feb 10, 2012


2 |
Share via:
What about watts per square meter of panel? Or average watt-hours per square meter per day? This would have to be measured over a given period of time, at a few reference amounts of insolation (say 3), and at a specific angle of incidence (say 75 degrees)? I'm sure I'm not the first to think of this -- isn't there some ASTM standard out there for measuring this? The standard should pick a time duration measurement period that captured the true capability of the panel. The other measurement standards should reflect "typical" operating conditions; the three levels of insolation should be chosen to approximate the observed averages at "southern", "mid-latitude", and "northern" U.S. locations (for example, 239, 197, and 156 Wh/m2, respectively). And the angle of incidence should NOT be 90 degrees, but the average angle of incidence over the span of a day for a typical, fixed-mount panel.