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solar grid tied
Grid-Tied PV Systems
A grid-tied system is one that is connected to electricity lines and generally does not function independently of them. A grid-tied system must include an inverter to convert the DC electricity coming from the panels to AC. If the electricity produced by PV does not cover all of the electricity required, the rest is supplied by the local electric utility. Inversely, if the PV system produces more energy than is being used on-site, excess energy flows back into the electric grid. If the utility allows Net Metering, the electric meter keeps track of this "net" difference as you generate electricity and take electricity from the electric grid. This way, the electric grid can serve as a sort of “storage” for energy produced, as excess electricity produced offsets electricity that would otherwise be purchased at full retail price from the grid. Net metering is available to solar energy producers for systems up to 25 kW in capacity in Oregon and up to 100kW in Washington. For more on this topic visit: www.dsireusa.org (net metering pages) and the NW Solar Center.
Following are
the basic components of a grid-connected photovoltaic system:
PV modules: A number of photovoltaic cells electrically interconnected and mounted together, usually in a sealed unit of convenient size for shipping, handling and assembling into arrays. The term "module" is often used interchangeably with the term "panel."
Mounting hardware: Used to mount the PV modules in place.
Combiner box: Where the electrical wiring from the PV modules is joined together in parallel to combine electrical currents.
Inverter: Converts the DC output of the PV system into usable AC output that can be fed directly into the building load.
Transformer (for large scale PV): Used to step up or down the voltage emerging from the inverter to match the required voltage of the onsite load or the utility interconnection.
Load: The amount of electricity used in the building.
