Tuesday, August 26, 2008

Five Steps to Solar Power

Get familiar with the word "photovoltaics" or "PV". The term basically means converting light to electrical current. Today, most PV systems--both residential and commercial--are connected to their local utility grid. Being grid-tied means no batteries are required and most incentives require connection to a utility. Now, here are five steps to buying a residential PV system:

  1. Know your power consumption
  2. Estimate PV system size
  3. Get three estimates
  4. Ask questions
  5. Select "Best Fit"

1) Know your consumption: Check your monthly kilowatt-hour usage (kWh) over the past year or, at least, six months including summer and winter months. Get the total charges and divide it by your total kWh for the whole period. (If your utility also supplies gas, be sure you're only calculating electricity charges.)

Example: Total Annual Consumption: 5000 kWh
Total Annual Charges: $600
Average Per kWH: .12

NOTE: Keep in mind your average monthly kWh usage; it will help you gauge system size. If you're paying 10 cents/kWh or less, solar power at this time will probably not save you money, expecially if your state or country has no solar incentives (See www.dsire-usa.org). The largest utilities in California have a base rate of .13/kWh goes up depending on consumption to as high as .485/kWh--nearly 50 cents per kilowatt hour!

2) Estimate system size: Let's keep this simple. A 2500WAC system (2.5kW) will generate about 4500 kWh annually in Phoenix, AZ. The same system in San Diego, CA 4200; Miami, FL 3970; Augusta, GA 3574; New York City, 3180; Ann Arbor, MI 2780. Need more power? Double the 2.5kW to a 5kW/AC system or find an appropriate size in between.

3) Get three estimates: Check with your relatives or friends first to see if they have or know of someone with a PV installation. Referrals can save you time and money but you still might get another bid for comparison. For safety's sake be sure installers are licensed electricians. You can also Google for local PV installers or go to FindSolar.com.

NOTE: Don't overlook the smaller PV installers; they can be more attentive than larger contractors and offer better pricing. Prices should be around $8.50 per AC Watt. Thus 2.5kWAC system (2500 watts) would be around $21,250 installed.

4) Ask questions: The three or more PV sales pros will perform an on-site survey of your house. Have your bills ready or a print-out of your billing history from your utility account online. Ask questions during the survey. If the salesperson gets the feeling you are fairly knowledgable about your power needs and PV in general, he will likely only propose what is necessary and not oversell. Ask for three references with contact numbers for inclusion in the proposal.

5) Select the Best Fit: Consider pricing, references, equipment and timing of installation process. Most installers will also handle rebate/tax credit paperwork as part of the total process. Also, the quality of the salesperson usually reflects the quality of his company. In California, as a requirement of the CA Solar Initiative (rebate), all systems are warranted for 10 years (panels 20-25 years by the mfrs). In short, feel good about the installer you chose; it's a long-term relationship.

A comparison of crystalline panels to thin-film PV will be featured soon on this blog.


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