Installation cost, solar systems requirements

A solar photovoltaic system contains, in addition to solar cells and module(s), an array structure to support the modules, power-conditioning circuitry for control and modification of the output, and a means of storing energy if required. All elements beyond the module are referred to as balance-of-system (BOS) components. The cost of BOS items is nominally about equal to the cost of the PV module. However, the BOS fractional cost contribution can vary from one- to two-thirds of the total installed cost of a system, depending on application. 

If the solar system is less ambitious and designed to provide only part of the heat, the cost of the solar collecting system is less. In this case, the cost of the solar harvesting system must be added to the cost a second heating plant to heat the house when solar heat is inadequate. With the combined costs of solar and conventional heating systems, the dual system requires 15 to 20 years for the savings in conventional fuel costs to equal the cost of the solar collectors. Because of the complexity, maintenance problems and costs there is little incentive to install solar heating in homes. 

Maintenance of a PSVE system is expected to cost 2% of the installed capital cost of the system per year. Operation and waste disposal costs are a function of concentration of contaminants and the airflow rate and will therefore vary widely (D14489S, p. 26). Once a system is installed, no utilities are generally required. If a valve and differential pressure control system are used, these could be run by solar-cell-powered batteries (D18119L, p. 384). 

Photovoltaic costs, in the committee s analysis, are for installed panels inclusive of structures to mount the solar panels themselves. A modular approach is expected to reduce the cost of such structures, although their contribution to the total system cost will continue to be significant owing to the size of the solar field that is required. 

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