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Why do grid-connected solar systems usually not need storage batteries?

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Diagram of a solar cell showing labeled layers, including a front electrical contact grid, antireflection layer, absorber layer, back junction layer, and back electrical contact layer, with arrows indicating light entering and terminals connecting to a circuit. — solar cell A commonly used solar cell structure. In many such cells, the absorber layer and the back junction layer are both made of the same material.

Grid-connected solar systems do not require storage batteries because they are integrated directly with public utility power grids.12

Unlike stand-alone systems, which rely on a bank of batteries to provide power during the night or overcast conditions, grid-connected systems use the utility grid as a virtual storage medium. In these setups, users can draw electricity from the grid when their solar array is not producing power, and in bidirectional systems, any excess energy generated by the solar panels can be fed back into the utility grid.132

This integration eliminates the need for battery storage, which reduces both capital and maintenance costs for the system owner. However, this configuration requires additional equipment, such as inverters and protective gear, to interface the low-voltage direct current (DC) output from the solar array with the high-voltage alternating current (AC) power grid.132