Stats After 2+ Years

Springtime has arrived, the sun is out more, and naturally we've been getting more questions about our solar panels! It's time for some fresh number crunching.

Since solar power is weather-dependent, there is definitely variation from year to year. Comparing our first two full years of production, the second year was a bit less spectacular than the first.

Forecast from analysis in 2009	Avg 9.5 KWH/Day
Actual first year (7/23/2009 through 7/23/2010)	Avg 9.9 KWH/Day
Actual second year (7/24/2010 through 7/22/2011)	Avg 8.7 KWH/Day

Looking at just the summer period, 2011 was higher than 2010:

7/24/2010 through 9/22/2010:	Avg 12.1 KWH/Day
7/23/2011 through 9/21/2011:	Avg 13.3 KWH/Day

However, this past winter 2011-2012 was more dreary than the previous two, as you can see in the following chart, which is derived from the renewable energy (production meter) readings from each utility billing period.

Hopefully 2012 spring weather will bring those average numbers back to where we expect!

As Seen On TV

I heard from many friends that they saw me on television. This past month, KIRO-TV (channel 7) in Seattle has been airing 30-second Sunergy Systems commercials that include my uncompensated testimonial and an intro by John Curley (both taped last summer). Here's a copy:

You can also find it on YouTube.

Wash Solar Panels?

Solar panel systems are intended to be largely maintenance-free, especially here in the Northwest where regular rains provide natural cleaning.

But we haven't had much rain the last few weeks, and I noticed some bird droppings on our panels, so I was curious if a manual cleaning would make much of a difference in power output.

This morning (before 9:00 AM), I did a quick hose spray and towel wipe down. I noticed dirt collects a little more at the bottom edge of each panel.

Now we can compare the energy output of two consecutive days with the same clear, sunny weather and similar high temperatures:

Dirty: 20.98 KWH (July 24, high 78°F)

Clean: 21.70 KWH (July 25, high 80°F)

The cleaner panels appear to eke out a few more electrons (+3%), restoring production to the same level as the brand-new system last year.