We use about 5,000 KWh per year. (This is below average.) We have 12 photovoltaic panels on the roof, each on capable of generating up to 190 watts, for a total of 2,280 watts (in ideal conditions). The rule of thumb used by the contractor is that the X watts of panels will produce approximately 1.15X KWh per year in Seattle. We've had the system a little less than three months, and have generated over 600 KWh. I feel like it's been a sunnier than normal late winter/early spring, though. Installation occured right after the most dreadfully rainy and dark Seattle winter I have experienced.
Installation also motivated a change in my behavior and I have reduced our electricity consumption significantly by reducing use of the electric clothes dryer.
Note: for anyone reading this outside Puget Sound, our electricity is dirt cheap. And our power is mostly (but not completely) generated by hydro, not by burning fossil fuels (although dams have their problems also). Twenty years ago I paid over 12 cents a KWh in Chicago. Here and now we pay 4 cents per KWh for the first tier of usage, 8 cents for second tier. We only get billed every two months -- it isn't even cost effective to bill us more often. And that 5000 KWh we used last year? We paid less than $3oo total. However, with climate change and population growth, that is changing. Energy costs, both in dollars and the effect on environment, are going up.
- No sales tax on the purchase or the installation (significant in this state)
- $2000 Federal tax credit for 2006.
- Net metering. When we generate more power than we use, our meter runs backwards and the energy is available for the rest of Seattle. In the summer, the meter will run backwards enough that we use a negative amount of City Light's power. We will still be billed for the monthly service fee, but that's it. The negative usage will be stored as a credit against usage next Fall. Net metering is done on a calendar year basis, so in the unlikely chance we still have a credit in December, we lose it.
- There's supposed to be a cost-recovery incentive program, although I don't have the final acknowledgement that this will truly happen. If it does, we will get paid 15 cents per KWh we produce for the next several years. Signs are good, but I am enough of a pessimist not to count on this "windfall" yet.
There's also a program for selling our "green tag" to power producers. I'm not sure that this still exists or that we would qualify, but if so, we could sell our claims for being green to the big guys for 5 cents a KWh. We would still be able to claim that we have photovoltaic panels and help produce clean power, but we would be very limited on what else we could say, for instance we could not say that we are helping to save the environment with our PV system. We would have sold that right to someone who purchased a green tag. I haven't pursued this yet.
Well, that's all for now. For more information, browse Puget Sound Solar website.