Determining The Location Of Solar Panels

• Before the physical installation of a solar power system, conduct a survey of the proposed location for the panels. Typically, panels are mounted on the roofs of buildings. The roofs must be positioned to accumulate the maximum amount of sunlight. In the United States, this generally means roofs that face east and south are acceptable locations. While the roof pitch (angle) does have an affect on panel output, most normal roof angles are acceptable. Next, observe the roof area during the five or six hours of the day when the sun is the strongest. Look for any shadows from trees, power lines, and other buildings or structures. Each solar panel on a roof (of the same pitch) is wired in series, similar to Christmas tree lights. Therefore, if one panel is shaded, the entire array of panels on the whole roof will suffer a reduced voltage output. Solar panels can be mounted on the ground, however, this usually requires a more expensive installation, as foundations and footings, typically of concrete, must be constructed.
  
  

Installation of Photovoltaic Panels

• Photovoltaic panels are usually mounted on rails. First, rafter beams are located, and lag screw brackets are attached to the roof, securing them to rafters. Long rails are then attached with clamps to the brackets, and solar panels are mounted on the rails. With this standard type of installation, the panels are actually elevated a few inches above the roof. This allows air to flow, keeping the roof underneath the panels cool, and also preventing mold and mildew from forming. Wiring from the panels may be run inside an attic or along the roof ridge, keeping the installation as esthetically pleasing as possible.
  
  

Inverters

• Electricity is generated by the sun hitting the material inside the solar panels. The power coming from the panels is in the form of DC (direct current). The wiring from the panels is fed into "inverters," electronic devices that change the DC voltage to AC (alternating current), which is the form for standard household electricity. The inverter handles the conversion and synchronizes the output to 60 Hertz (60 cycles). The building's electrical system remains tied to the local utility company's power grid. When the solar panels are not producing enough power to meet the demands of the building, the extra needed electricity is pulled from the power company's grid. When the solar panels produce more electricity than the building is using, the extra power is sent back to the grid. The electric meter runs backwards when power is sent to the grid, giving a credit for electrical use on the customer's electric bill. The traditional electric meter, though it can run backwards, is usually replaced with a "net meter" by the electric utility company, as this digital meter is more accurate than mechanical meters. At the end of the year, the utility company will send a check to the customer to pay for any power generated above that which is used. Inverters have digital readouts on their front panel to indicate the amount of power being generated by the system. Some models are mounted indoors, while others are designed for outdoor use, where they should preferably be mounted in a shaded area.
  
  

Blackout Scenario

• When the electricity on the grid goes down, the inverters automatically disconnect the solar panels from the grid. This is required by law. Therefore, even though a building has solar panels, it will not have electricity if the utility company's power goes out. Sending power back to the grid from a solar system during a blackout would hamper troubleshooting by electric company linemen, and also put their lives in danger. Storage of electricity from solar panels is only employed in remote locations where there is no access to utility grids. Storage batteries are incredibly expensive--costing hundreds of dollars each and many are needed, depending on the electrical requirements of the building--have an unpleasant odor and require a massive amount of room.