Tuesday, June 17, 2008

Charting Seasonal Output

Now that many of us who got solar in 2007 have completed our first solar year, some interesting results are available for those of us who have charted our usage. The graph above shows the average value (in dollars) of my solar system's daily output over the 13 month period from 5/15/07 to 6/15/08. (I'm on the E-7 rate plan, which is no longer available to new solar households).
Because the E-7 peak rate is $0.28 from May 1-Oct. 31 and only $0.10 from Nov. 1 to Apr. 30, my solar system generates very little value for six months of the year. (It faces WNW, which exaggerates this effect compared to a South-facing system.) So, if I ever need to take my solar system offline to re-roof, I whould do it in early November when the weather here is usually quite nice (but the value of my solar output is paltry.)