How a Photovoltaic Grid-Tie System Works

System Operation
Independence Series commercial solar electric power systems convert sunlight into utility grade electricity that can be used at the property, with excess capacity sold back to the power company. Independence Series systems consist of an array of PV modules, a UL listed, utility-grade inverter and all required wiring, mounting structures and safety devices.

When a home or business requires more electricity than the system is generating (for example, in the evening), the need is automatically met by power from the utility grid. When less electricity is required than the system is generating, the excess is fed (or sold) back to the utility. The power generated by the system exactly matches the voltage and frequency of the electricity flowing in the utility line, and also meets the utility’s safety and power-quality requirements. Safety switches in the inverter automatically disconnect the system from the line if utility power fails. Used this way, the utility backs up the system like batteries do in stand-alone PV systems. At the end of the month, a credit for electricity sold is deducted from charges for electricity purchased.