Second Billing Year Data

2004-2005

On November 26 one of inverters stopped working. A few months later I noticed that our production for the year was down 25% from the previous year. Somehow we didn't think to check the inverter and blamed it instead on an overcast season, and not having washed our panels. We saved $1868 this year on 8678 KWH of PV production (an average of 21 cents per KWH). How much more would we have saved if we had the inverter fixed earlier?

On August 3, 2004 we changed from E-8 Seasonal billing to E-7 Time-of-Use billing. You can see we saved more during the two weeks we were on the E-7 schedule ($142) than we saved during the previous two weeks we were on the E-8 schedule ($109).

On July 17, the surcharge on electric usage from 131-200% of baseline dropped from 0.05124 to 0.0358 cents/KWH. The surcharge for 201%-300% of baseline dropped from .0.09517 to 0.0665 cents/KWH. The surcharge for over 300% of baseline dropped from 0.11505 to 0.0665 cents/KWH. So while we still save just as much with E-7 compared with E-8, we are saving less with the solar panels vs no-solar panels than last year.

Surcharges changed again up in September, down in December, up in January, down in March and up in June. It's been a bit annoying trying to keep track of all the changes. I don't know how much of the increase from saving 20 cents/KWH last year to saving 25 cents/KWH this year is because of the E-7 schedule and how much is because since we were making fewer KWH, they were replacing energy at mostly the higher rate tiers.

This winter has been more rainy than last winter.

In the rainy winter months (Nov 1 - Apr 30), it costs a little more to be on the E-7 Time-of-Use schedule, compared with the E-8 Seasonal schedule. In the summer months (May 1 - Oct 31), it saves a lot of money to be on the E-7 TOU schedule. If I had noticed that one of the three inverters had failed in November and had it fixed then, maybe we would have saved money with E-7 as compared with E-8 even in the winter months.

During our first year with solar power, our average household power consumption was 45 KWH/day. So far in the second year, we're averaging 53KWH/day. I'm not sure where all that power is going. In 2004 the air conditioning maintenance guy said our unit was low on refrigerant and he added some. In 2005 the breaker for the AC kept on tripping and we called in a different AC maintenance guy who said there was too much refrigerant. We did get a jacuzzi whirlpool spa. We got a commercial freezer. I am using my laptop more. We might be leaving the lights on more. I really should use Kill-a-Watt meter, to track down where the power's going. On the other hand, over the winter I installed some whole house fans, 1500 CFM each, to turn on in the summer evenings around 5pm when the temperature in the house is still rising but the temperature outside starts dropping below the indoor temperature. This has decreased our A/C usage during the summer. I figured it would use less power to have the three 1500 CFM fans running for 8 hours compared with running the AC for one hour.

This year we refinanced our mortgage from 5.75% to 5.00% with 1 point. This will lower the payments to pay off the solar panels, but it will also extend the length of the mortgage by 2 years. We should come out ahead on the mortgage if we keep our house for 4 more years, which we expect to.

last changed 2009.09.19