[RE-wrenches] Power Loss from Dust on PV Modules

[Peter Parrish]

With most of our systems being sold in an urban setting, we have found that
-- without a doubt -- proximity to a freeway, any freeway, is the single
most important factor contributing to accumulation of dust/dirt.

I can't tell you exactly where to draw the line, but 500 feet puts the
system within the "zone", and 5,000 ft (1 mile) puts the system outside the
"zone".

One unfortunate customer of ours in Glendale, CA was 550 ft from the 2
Freeway, but no one was aware of the fact because of an intervening ridge.
He needs to wash his panels 3 to 4 times a year to prevent significant loss
of production (10%). This is less of a problem in the winter, and we don't
recommend washing PV panels from November 1st to April 1st.

- Peter
                                                     
Peter T. Parrish, Ph.D., President
California Solar Engineering, Inc.
820 Cynthia Ave., Los Angeles, CA 90065
CA Lic. 854779, NABCEP Cert. 031806-26
peter.parrish at calsolareng.com  
Ph 323-258-8883, Mobile 323-839-6108, Fax 323-258-8885