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Glossary

Sizing a system is a fairly complex task with abundant room for errors. Thus, it is a good place for a professional.

A professional starts by looking at your existing home's electrical consumption based on historical records and any new additions to your load. He/she uses a projected load for a new home. The professional then weighs your electrical consumption against solar needs to determine the size of your system

The size of your electric system depends on

• Solar insolation (amount of sunlight you receive)
• The efficiency of your system
• Electrical demand
• Temperature
• The consumption of electricity by your family.

Solar radiation varies from one region of the world to another. The more sunlight you receive, of course, the more electricity you can generate. Texas has more than adequate sunlight to make a solar system feasible.

Check to see that you also have:

• Open lot or property (nothing is blocking or shading your sun).
• The site of your home is properly oriented toward the sun.

Examine your utility bills to get an average use of electricity during the year. The size of the system is based on an estimated demand to which you should add some efficiency losses.

There are two ways to size your system:

1. Work from your electricity needs.

• Determine your average daily electrical requirements.
• Determine PV electrical output in your area.
• Determine the size of the PV array needed to meet your electrical demand.

2. Work backwards from your budget.

• Buy as much as you can afford now.
• Buy more as you can afford it.

Check your estimates with a professional. You will get an estimate of the amount of energy that the system will produce on an annual or monthly basis. Because the amount of energy depends on so  many variables, the contractor will probably not quote a specific figure but will give you a range. A range of plus/minus 20% is realistic.

Don't forget energy efficiency to lower electrical needs. Find creative ways to stop energy use.  

One last thing: Add some capacity. Most people either underestimate their electricity needs or they begin to use more electricity when it is either "free" or reduced in price. Adding capacity is particularly important if you are living "off grid."

Green  & 
Renewable Energy
972 251-1532 or 
817 433-2553