Just got my first yearly bill from PG&E, reflecting the performance of our solar array.  Good news - right about where I expected it to be!  Here’s the stats for those that need encouragement to take the solar plunge:

• Power generated: 13,315 kWh
• Power bought from PG&E: 3,358 kWh
• Annual bill from the power company: $348.00
• Sum of monthly minimum payments for connected meters: ~$50
• Savings: $3,221.14 [1]
• Actual rate of return: 8.95% [2]
• Total payback length: 11.2 years [3]
• Extrapolated payback date: 11 Oct 2017

Notes:

1. This calculation takes into account the sliding price scale for energy over the baseline, and actual changes in the rates and baseline during the year.  Some straight-line averaging was necessary to correlate the readings taken from the meter with those from the power company.
2. Tax free!  And calculated only over the payback period - once the array pays for itself, I will continue to get free energy for many years.
3. Straight-line extrapolation based on assumed fixed consumption, and fixed energy prices.  It is virtually impossible that energy prices won’t rise substantially in the next 10 years, shortening the payback period and increasing the rate of return.