It's been nearly a full year since we had our 6.1KW solar power system installed. During that year, we experienced the peak of summer and the low point of winter. Sunnyvale, California is at 37 degrees, 22 minutes north latitude, 122 degrees, 2 minutes west longitude. That means we're south of the 45th parallel, which means more sun year round, but less sun during the peak summer daylight hours.
June 23, 2009, by Loyd Case
Originally published on ExtremeTech.com
I've written extensively about our solar power installation I had installed back in May 2008 along with a one month update and a Q&A on my installation.
At the six month update, I wrote about the doldrums of winter, and gave an update on power generation, power usage, and cost.
At the one year mark, I received the true-up bill from PG&E, so I know exactly how much I paid over the year, as well as the monthly breakdowns. Let's dive into the numbers, shall we?
Power Generation: Twelve Months
|
July 31, 2008 |
Dec. 31, 2008 |
March 31, 2009 |
June 17, 2009 |
|
| First Non-Zero Reading |
6:20AM |
7:41AM |
7:03AM |
6:03AM |
|
| Peak Output |
4,812W @ 2:20PM |
3,158W @ 12:53PM |
4498W @ 1:55PM |
4834W @ 2:12PM |
|
| Last Non-Zero Reading |
8:07PM |
4:55PM |
7:23PM |
8:26PM |
|
| Total Output |
38.58KWh |
8.05KWh |
31.39KWh |
38.72KWh |
As we move out of winter and into late spring, the number of daylight hours has increased. That affects overall output. Note how first non-zero outputs start earlier in spring and summer and taper off later in the evening.
It's worth looking at a few sample days, charted out in their entirety. Since it's not quite the end of June as I write this, I picked June 17th as a representative day for late spring / early summer.