Generating solar power for your neighbour’s home

Prompted by a blogger’s question about the poor return by utility companies for power generated by a home solar power system, Doug, from Southern California, shares his experience:

SoCal Edison has a graduated billing structure where the first 10kWh/day (baseline) are billed at $0.07, the next at $0.10, and so on until you get 200% over baseline and the rate is over 40 cents per kWh -- it is a killer if you have a pool, central air conditioning (AC), koi pond (pumps run 24 hours a day), etc.

I installed the solar power system because I felt bad about the amount of energy my house was consuming. I installed compact fluorescent bulbs, timers, motion activated outdoor lights, etc., but with the pool and the ponds and the AC, no matter what I did, I was going to consume 800 kWh to 1.5 mWh per month ($200 - $400 a month).

In Southern California the utilities are required to have meters that turn both ways. (This may be a Federal requirement now.) Here anyway, the utilities have to buy it back at the same rate they sell it, so if you produce baseline amounts, they buy it back at $0.07, if you produce more, they have to buy it back at the higher rates.

Bottom line, though, is that my billing cycle is 12 months -- if after 12 months I have used more electricity than I produced, I have to pay them. If after 12 months I have produced more than I used, they zero out the account, say thank you (maybe) and we start all over again. They will not actually pay you after 12 months for any surplus. I don't think it is right, but that is where it stands today.

Because we were running 200% over baseline on a significant portion of our bill, it made the ROI on the PV system about seven years assuming no rate increases. The panels are warranted for 25 years, so it is a pretty attractive proposition if you are on a graduated billing structure and you are a heavy user.

Now I am a net producer of electricity -- I am actually supplying my neighbours with electricity. The nice thing about PV here in Southern California is that AC is a huge consumer of electricity, and that consumption occurs at peak solar hours, so the Photovoltaic (PV) systems are helping to limit the peak consumption spikes when the utilities need it most (ahem, that is if your AC does not cause your PV system to go off-line for 15 minutes out of the hour).

Also if you are a tool head, it is kind of cool to watch the meters, and monitor what you produced each day.  Before I go to work in the morning I check the inverter and utility meter, and then when I come home I do it again to see how much surplus electricity we produced for the day.

Cool bright days produce the most power-- the panels lose efficiency at higher temperatures. On my 6kW system, we produce just a little less than one million watt hours per month.

7 September 2007