Thoughts on Solar

Here in SoCal we are blessed with endless warm sunny days. The down side however is that it can be many months between invaluable air-purifying rain showers. For your solar array, this means there is nothing to wash away the accumulated dust and detritus from nearby trees. In summer months ash from nearby mountain fires adds to the mix. Consider this a Run on Sun PSA…

IT’S TIME TO RINSE OFF YOUR PANELS!! 

These panels needed to be cleaned just to get the inverter to turn on!

(Didn’t help that the installer put the panels under a tree!)

When discussing solar with new clients often the topic of cleaning comes up. This is because some solar companies use the concept of cleaning your array as a way to convince you you need a leased system with ongoing maintenance. However, we believe this is a bit of a scam. You don’t need to pay someone to get up on your roof with a squeegie every week. Most home owners have the ability to douse dusty panels from the ground with a strong nozzle attached to a garden hose. Really the benefit is nominal unless it has been six months since the last rain, such as the case in Southern California. As for cleaning the panels, rinsing with a hose is fine (though some insist that is heresy and only deionized water should be used). Do it first thing in the morning so there is no thermal shock to the panels.

Check out this recent case study that brought this issue to our attention:

Shiny new panels at Chandler School

Last week we heard from a client who did some great analysis using the Enphase monitoring on their system before and after he decided to clean his panels. He found there was an 8% improvement in the period after cleaning. Run on Sun’s CEO Jim Jenal compared this to the monitoring on another system (Westridge School) which wasn’t cleaned and had a similarly unshaded southern facing array. Over that time period Westridge School’s daily average production reduced 8.66%. This means that our client actually had an increase of production of 16.6% by cleaning his panels!

Generally, cleaning an array results in an improvement of between 5-10%, so his panels were exceptionally impaired by the fallout from our summer fires! Not surprisingly, given his location in the foothills of the San Gabriel Mountains. However, for anyone in the Los Angeles metro area, early September is a great time to get out and restore the shiny clean sheen to your array. After all, who knows when the first winter rain will come?