Now is a great time to invest in a solar power (PV) system. The cost of solar panels, the component you see on rooftops and the most expensive individual component, has come down since 2008. Tax and utility incentives bring the net cost of a photovoltaic system down to a manageable amount for many people. Cost recovery can take six to eight years. After that, all of your system power is effectively free.
The following are the most important aspects to consider when designing your photovoltaic system.
- Matrix Orientation The solar panel array should be as close to south (180 degrees) as possible. An array that is off azimuth (facing other than south) provides less power. A traditional PV system panel needs approximately 16 square feet of roof area for every 200 watts of power. For example, a 4,000-watt PV system needs approximately 320 square feet of south-facing roof area.
- Die tilt angle An ideal array will have the sun at a 180 degree angle to the array for as much of the day as possible. The ideal roof pitch where the array will be mounted depends on your local latitude. A higher latitude means a higher pitched roof is required to create the ideal pitch angle. Few PV systems have an ideal tilt angle. An array with a more oblique rake angle provides less power, but it may not be worth spending too much extra money just to create the ideal rake angle.
- shade Trees, buildings, chimneys, and other things that cast a shadow on the array at any time during the day reduce the power output of the PV system. Locate the solar panel array to avoid shade.
- Roof deck condition The panels of the photovoltaic system can last twenty-five years or more. This is longer than the design life of most roof deck materials. Ideally, you should install the panels over a roof deck that will last as long as the panels. Otherwise, you may have to remove the panels when installing a new roof deck.
- Component Location Electric utility companies typically require quick access to the AC disconnect switch so their staff can make sure the PV system is off while they work on your equipment. This often means locating the AC disconnect switch near the meter or some other point that is not behind doors or gates that may be closed. The inverter and DC disconnect switch can, in theory, be located anywhere that is accessible. If you are outdoors, the inverter should be shaded and protected from the elements as much as possible.
- Status of the electrical panel Solar systems typically require two circuit breaker slots in the electrical panel to connect power from the PV system to the home’s electrical system. If your electrical panel has no more circuit breaker slots or is an older panel that contains fuses, panel changes or a complete panel upgrade may be required.
Solar power systems can work in almost any environment, when designed and installed correctly. Doing your part to help your country achieve energy and help the environment feel good independence. Significantly reduced electricity bills feel good too.
