Solar Performance - May 2015

This month got off to a strong start with a string of sunny days, but around mid-month the traditional Seattle "June Gloom" rolled in early and put a real damper on production. The month ended up just a little shy of estimates, about 6 kWh short of the expected 469 kWh. I'm also lacking some of the usual efficiency metrics for the month since my weather data source was offline from 5/11 - 5/27.

In better news, production was up over last month and was slightly (1 kWh) ahead of last year. My electricity usage was also down, both year-over-year and month-over-month.

Looking at the year as a whole, production is slightly ahead of last year and well ahead of estimates. I'm interested to see how the June - August numbers turn out since those were all below estimates last year. My annual surplus is also continuing to build nicely.

At the individual panel level there's some interesting behavior this month. Each of the west-facing panels produced noticeably more than the east-facing panels. This seems consistent with the weather patterns we had on cloudy days: clouds in the morning giving way to sun in the afternoon and evening.