WILEY

Solar Installation FAQs...

What does PV stand for?

Photovoltaic. This refers to the ability of solar modules to transform light, photons, into electricity which has the characteristics of voltage and current.

What are the components required for a PV system?

1. Solar modules - sometimes also called solar panels.
2. A location of sufficient size for the modules and which receives sunlight most of the day. A mechanical mounting system to hold the modules in place there.
3. An inverter which changes the direct current (DC) electricity from the modules into alternating current (AC) compatible with that delivered by the utility company.
4. Safety switches which are required to allow maintenance on the system.
5. Wiring to connect the components together. Some portions will be in protective conduit.

What is net metering?

Utilities are required to allow customers to connect PV systems to their delivery lines. When the PV system produces more electricity than is used, the electric meter will run backwards. When more electricity is used, the electric meter runs forward. The customer pays based on the net amount of electricity used.

How are solar modules mounted?

There are three types of mounting methods commonly used. In order of increasing cost and complexity are roof mount, ground mount and pole mount. The mounting method is generally chosen to achieve good exposure to the sun or to match the architecture of the installation site.

roof mount

For composite shingle roofs, brackets are attached through the shingles to the rafters below. Aluminum rails mount to the brackets and the solar modules in turn mount to the rail. Most modern houses have rafters on 24 inch centers and are able to support the additional weight of the mounts plus modules. Older houses may need reinforcement of the rafters.

Tile and slate roofs require more complicated mounting and are therefore more expensive, but solar modules which take the place of slate are available and provide a very esthetically pleasing installation. For flat roofs, as commonly found on commercial buildings, a free-standing ballasted design is available which avoids any penetrations of the roof.

ground mount

The base of a ground mounted system is a number of concrete piers. For stability, the pier extends below the depth of the frost line, which depends on climate. Metal racking attaches to the piers and provides a stable mounting surface for the solar modules. The ground mount has flexibility in placement for best solar exposure and esthetic appeal, although, since wires must carry the electricity generated by the modules to the house, it is most efficient and economical to install the ground mount close to the building it will supply.

pole mount

Pole mount systems are used to avoid shading or where for placement reasons the modules should be elevated. A large diameter steel pole embedded in concrete provides the stability needed to withstand wind loads.

How much does a PV system cost?

Right now, federal and state incentives are available to encourage homeowners to install these systems. The cost of the electricity generated is competitive in price to current utility rates. Furthermore, a PV system will keep generating electricity for the next 20 years while the price of electricity from the utility will continue to rise. Some immeasurable benefits are the fact that the power generated by a PV system does not cause pollution like that generated by the utility and that PV systems help reduce our country’s reliance on foreign oil.

Pricing for an individual system depends on the mounting method and size of the system installed. The amount of reduction in an individuals utility bill will also depend on a number of factors such as level of insulation, type of appliances, and lighting. Also, due to the rapidly growing popularity of PV systems, the price and availability of solar modules has been rising. For these reasons, it is necessary to treat each situation individually. Please give us a call.