In a renewable energy system, the balance-of-system (BOS) is a quantity that refers to all components other than the mechanism used to harvest the resource (such as solar panels or a wind turbine) and the application or load. It includes support structures, power conditioning equipment, batteries, and indirect storage. In addition, the balance-of-system may also be taken to include design costs, land, site preparation, system installation, operation and maintenance costs, and related costs.

 

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small solar electric system balance-of-system components

small wind electric system balance-of-system components