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by Bruce Karney

Are you a Bay Area homeowner who is thinking about installing solar photovoltaic panels on your roof to help fight global warming? Good for you. You may be the first on your block, but you are probably far from the first in the Bay Area. I know one man, an architect, who put solar panels on his home in 1984.

There is a lot of excitement about new solar panel technology, but more likely than not you will choose to install modules that use the same basic technology that was available in 1984. They are a proven, long-lasting way to convert sunlight into electricity. The latest models have decent efficiency, turning about 20% of the energy that strikes them into power. New technologies continually make the news, but for the most part are only applicable to very large commercial installations, not residential rooftops.

Here are 10 things you should know before speaking with a solar salesperson:

1. Your system will not need batteries. At night, you will get your power from PG&E's grid, just like you do today.



2. Make sure you understand PG&E's electricity rates. There are currently five tiers. Each tier has a different cost. If you are a frugal household, you may be able to get all your energy needs at the Tier 1 rate, currently $.11 per kilowatt-hour (KWH). As your energy use rises, you pay Tier 2 rates ($.13 / KWH), then Tier 3 ($.23), Tier 4 ($.32) and Tier 5 ($.37). A typical electric bill is about $87 per month, which means that you have used all of your Tier 1 and 2 allotments and that your marginal price is $.23 per KWH. If your monthly electric bill is over $237, you are up into Tier 5 territory. When you add a solar system to your roof, you eliminate the top tiers first. So, the more you spend on electricity now, the higher the return on investment you woll get from a solar system.



3. Solar panels last about 30 years, losing approximate 0.5% of their efficiency each year. The only required maintenance is to hose them off a couple of times each summer. Do this from the ground, with a nozzle on your hose. The inverter, which converts direct current from the panels to alternating current used in your home, will need to be replaced after about 15 years. Expect to pay $2000 for the part and $400 for the labor sometime around 2022.



4. Ideally, a solar system will go on a southwest-facing roof. However, the direction it faces does not matter as much as you might think. West and south are quite good and southeast, east and north-northwest can provide good payback too.



5. Know exactly how much electricity your home uses each month. If you keep old bills, great. Otherwise, request the data from PG&E. But also think about how your electricity needs will change over the next 10 years. If your family is growing, you will need more energy as your kids grow. On the other hand, if your nest is about to become empty, you may expect that your energy bills will decline and stay low. If you plan to replace incandescent lights with compact fluorescents or do other things that will make a big difference in the amount of electricity you use, you should ask the salesperson to base their bid on your PLANNED electricity use, not your actual use.



6. Solar power's natural enemy is shade. One of the key things a salesperson will do when they climb on your roof is to get a very good understanding of how the roof is shaded in different seasons. You and the sales rep will have to think about the growth of trees over 10-30 years. Some trees that shade your roof may be several houses away from yours - tall redwoods for example. Even if your current neighbors are good friend and will trim their tree that shades your roof if you ask, what if they move in 2 years and the Grumpy family moves next door?



7. State rebates (administered by the California Energy Commission) and Federal tax credits (which you claim on your 1040 Tax Form) are an important part of the cost/benefit decision. California state rebates are declining step-by-step. The maximum rebate as of April 2007 is $2.50 per AC watt. For the next year or so, rebates will probably decline faster than prices, so when the sales person tells you it is cheaper to buy now then to wait, it is the truth.



8. Most families that go solar switch to "time of use" metering. Under time of use electricity costs more in times of high demand. PG&E has two rate schedules. The more favorable for solar owners is called E7. It has "peak" and "off-peak" periods. Prices vary by Winter and Summer as well. The summer peak price is $.29 per kilowatt-hour (KWH), the off-peak price is $.09. The E6 rate has another category called "partial peak." Its summer rates are: peak $.21, partial peak $.11, off-peak $.09. Now, you probably think that the E6 sounds like a better deal, because the price is lower - but that is probably becaise you are thinking like an energy consumer instead of an energy producer. Once you have solar on your roof, you will be selling electricity that exceeds your usage to PG&E. When your system is cranking out power on a sunny summer afternoon, you will want to get $.29/KWH instead of $.20. The E7 rate is going away, so be sure to ask your sales rep if it is still available. Being able to get onto the E7 rate schedule is another reason to act now rather than later.



9. It is very difficult to know how much a solar system will add to the value of your home at resale. People who install solar systems generally plan to stay in their homes a long time, so re-sales are rare. I think it is fair to say that 5 or 10 years from now potential buyers will be much better able to assess the value of a low electric bill.



10. You can not actually lower your electric bill to zero. PG&E will buy your power, but only to the extent that it drives your net energy bill to zero. They will also charge you a monthly "account fee" of about $5/month that covers services like maintaining the grid and coming to read your meter. PG&E will, on the other hand, take all the power your system produce in excess of your needs, so you should not "oversize" your system.

Talk to several solar companies before you make a commitment. You will probably find that their prices are very similar, so your final decision may be made based on intangibles. Any reputable solar salesperson will give you one piece of advice before they sell to you, and I will do the same. The advice is: first conserve, by identifying electricity wasters in your home. Conserving is cheap. Only after you have conserved should you invest in solar. Do a web search on "conserving electricity," read the suggestions and implement as many as you can.

If you are interested in the details of solar system financing, installing, maintenance and monitoring, read Part II of Solar System Must-Knows

For questions or comments about this article, please write to us at feedback@organicpicks.com

Copyright 2007 by Bruce Karney

 

 

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