A benefit to self generation is that the first watt of power you put into the Grid, is usually at the HIGHEST rate you are paying PGE. If you are on a TOU-time of use meter (peak and off peak) coupled with typically going into the 3rd and 4th tier on your bill, you could be paying as much as 64 cents a kilowatt. The watts your PV array or wind turbine pump into the system start at the top rate!!!.. Your returns are highest from the start!!
Example, Your solar PV system makes 25kw in a day during the peak hours of 11 to 7. Peak rates apply and are about 40 cents. Add to that, the likelyhood that your residential meter runs into the 4th and 5th tier in the summer and you are paying 65 cents a kw. So those 25 kw may only represent 25% of your daily usage, but will make up about 80% of your costs, by being pumped into the grid at the highest rates.
HOW DOES THE METERING WORK??
With residential meters, we have NO choices with the tiered system. The more you use, the higher your rate. Within your base line, you pay about 15 cents per KW. In the 5th tier (common in summer) you will pay close to 64 cents per kw.
We do have a choice in the type of meter we choose. Flat rate, or time of use. (TOU)
TOU provides cheap power in the off peak times (peak is 11am to 7pm) IF you can control your usage to the off peak times, you will have a base rate of about 9 cents. The peak rate is about 35 cents. This means that your self gen system will be pumping 35 cent power to your credit from 11 to 7 every day, and you will be using the power in the off peak times at 9 cents. You need a house with GOOD insulation, and exposure to benefit from the TOU system. If you can cool your house in the morning (till 11am) and it will hold the cool to 7pm. then this meter works great.
How to determine??? Do a simple test. Turn your AC to 70 in the morning and turn it off at 11AM. Note your inside temp. Check that temp at 7pm and see if you are OK with it. Yes.....go TOU. IF it is to hot, go flat rate.
How big a system do you need?
Take a look at the last 12 months of bills, Total your KW usage. This is your annual KW usage.
Now look at the June through Oct bills. IF they are really most of the bill, then more considerations are needed. In the North Valley, a 5kw solar system will give you about 35kw a day during May to Sept. Compare this to your total usage. Remember, you don't have to match kw for kw. The timing of the energy production will let you keep your kw off balance yet your $in balance.
Want to go energy independent? You can eliminate your gas bills too by converting to all electric and making your own power with solar hot water and solar PV.
An electric heat pump would heat your house instead of the gas furnace.. If you had a big enough self gen system, it would provide both summer and winter for free. For simplicity sake, use the dollar to convert your gas dollars to electric and see how many more KW that would add.
Hot water is expensive!!! Solar hot water is the best bang for the buck. We recommend
www.solarroofs.com. We can provide and install this system for you. Check their web site.
Generally speaking, if you install a PV system that provides half to 3/4 of your total KW usage, your bill will drop drastically. IN Northern Calif, figure 5.5 hours a day for 365 days a year. A 1000watt or 1kw system will provide 5.5kw a day for 365 days or. 2000kw a year. Using multiples of this, you can get a basic idea of your needs.
Click the
Solar System Costs link here for your next step.
