DEBRIS.COMgood for a laugh, or possibly an aneurysm

Our 2005 “trueup” bill arrived from PG&E. My total electricity cost for 2005: $56.68, or about $1000 less than it would be if I didn’t have a PV array on the roof.

In 2004 we paid only $6.53 for the year’s power. The difference is small, but growing. (His name is Raphael.) We’re keeping the house warmer, and doing an extra 4 loads of laundry a week. And our houseguests come more often and stay longer, and use a whole bunch of power when they’re here.

I’ve baked 33% fewer times this year than last, but the savings in oven power have been eclipsed by higher uses elsewhere. I thought my new low-power firewall would have made some small contribution to our conservation efforts, but I can’t see it on the graphs. Computers just don’t draw that much power, unless you have about a million of them.

PG&E keeps a running tally of our outstanding charges, billing only at the end of the annual cycle. The idea for grid-tied systems is that consumption is bigger than generation in the winter, but smaller in the summer, and that after 12 months the balance should be near zero — assuming the system was sized correctly. In 2004, we were only off by $6.53.

The graph for the past two years’ running charges shows the cycle clearly. The 2005 line is offset by about $40, which I guess is the cost of adding a body (even a small one) to the household.

As a sanity check, I graphed our generation for both years. Total generation for 2005 was about 9 kWh higher, so I didn’t expect large differences month-to-month. The array reconfiguration in October, 2004 appears not to have had much impact.

Our installer should soon be running a comprehensive year-end analysis to determine our actual energy savings. I’m interested in this because, in essence, I paid for 10-12 years’ worth of electricity in 2003, and I’m eager to break even — every dollar I don’t pay PG&E now is another dollar’s reimbursement on my initial investment, bringing me closer to those 20 years of free electricity I have coming.