Solar: Photovoltaic(PV) Solar Systems
There are two main forms of photovoltaic solar systems for residential use: grid-tie and off-grid.
Grid-tie System:
A grid-tie system allows for a home to have solar cells installed on or near a home that collect the sun’s energy and convert it into DC electricity. Then the inverter converts the DC power into AC power, which can be used directly in your home. Electricity produced by the solar cells that is not used immediately in the home is returned to the power grid. When this happens your renewable energy meter spins forward paying you for everything you produce and your electricity meter literally spins backwards as you are passing energy to the grid. For all the excess energy you produce, you receive a credit on your power bill. This is referred to as “net metering”. The benefit of the grid-tie system is that it does not require you to use expensive batteries to store power. The grid acts as the storage system and your home and the grid exchange power as you need and produce it.
Off-Grid System:
An off-grid or stand alone system is typically used for remote locations where standard grid-based power is not available. These systems allow for complete electrical independence. These systems require deep-cycle batteries for storing the electricity as well as a charge controller to assure the flow of electricity from the cells does not over-charge the batteries.
Glossary of Terms:
- PV Array - The part of the system that converts sunlight to electricity.
- Inverter - The device that changes the electric current that the solar cells produce DC (direct current) into AC (alternating current). The type of power required by most of the conventional appliances in your home. From the inverter the electricity will be used by the appliances and systems in your home or go out onto the grid.
