Wal-Mart’s bid to install solar energy systems in its stores in five states could boost the solar industry as a sign of corporate interest in sustainable technologies and practices.

Photovoltaic cells—solar cells—change sunlight into electricity directly via semiconductor materials such as crystalline silicon, and new buildings are increasingly including solar panels as a source of electric power.

Standards from the American National Standards Institute such as UL 1703-2004, “Standard for Safety for Flat-Plate Photovoltaic Modules and Panels,” help support this solar technology. Underwriters Laboratories publishes UL 1703-244, which covers mounting and electrical components and functions in accord with the National Electrical Code, NFPA 70 and model building codes.

Solar collectors are used to heat a transfer medium that supplies heat energy for space or hot water heating, and can have its performance tested by methods in ANSI/ASHRAE 93-2003, “Methods of Testing to Determine the Thermal Performance of Solar Collectors,” which was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers.

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