A grid-tied solar power system (also referred to as grid-intertied, or on-grid or utility-interactive (UI)) produces solar electricity that is fed directly into the utility grid, hence the term grid-tied, as the system is tied, literally, in a grid tied system any surplus power generated is sold back to the power utilities. When the sun is not shining one can buy power back from the utilities. This is done using net metering; a method of metering the energy consumed and produced using a renewable energy generator.
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