ANSI - American National Standards Institute
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As Big Business Looks to the Sun, Standards Support Solar Technology

New York, Jan 12, 2007

Wal-Mart, the world's biggest retailer and the nation's largest private energy user, has turned its eyes to the sun as a potential sustainable source for the company’s colossal energy needs. The retail giant is seeking bids to install solar energy systems on available roofing space across stores in five states nationwide. The move is indicative of a growing corporate interest in sustainable practices and technologies, and could give the solar industry an enormous boost. If realized, Wal-Mart’s plan to install solar power to the tune of 100 megawatts would exceed the world’s largest solar installation to date by a factor of sixty. Several standards from ANSI-accredited standards developers are helping to support this emerging technology.

Solar cells, or photovoltaic cells, convert sunlight directly into electricity by means of semiconductor materials such as crystalline silicon. They are the building blocks of solar energy, capable of being grouped and connected to meet the desired voltage and current. Semiconductor Equipment and Materials International, known as SEMI, has published a standard that covers silicon wafers used in the manufacture of photovoltaic solar cells. SEMI M6-1000, Specification for Silicon Wafers for Use as Photovoltaic Solar Cells, specifies dimensional characteristics, crystalline defects and commonly used wafer electronic properties for mono- and multi- crystalline silicon materials.

Increasingly, solar panels are being incorporated into the roof or walls of new buildings as a principal or auxiliary source of electric power. Or, as in the Wal-Mart proposal, panels can be retrofitted into existing buildings, in which case they are usually fitted on top of the existing roof structure or located apart from the building, but connected by a power-supplying cable. UL 1703-2004, Standard for Safety for Flat-Plate Photovoltaic Modules and Panels, is the American National Standard that details requirements for flat-plate photovoltaic modules and panels either intended for integral installation on buildings, or to be freestanding. Published by Underwriters Laboratories, the standard also covers electrical and mounting components for PV modules and panels. UL 1703 works in accordance with the National Electrical Code, NFPA 70, and Model Building Codes.

The Institute of Electrical and Electronics Engineers (IEEE) standard, IEEE 1526-2003, Recommended Practice for Testing the Performance of Stand-alone Photovoltaic Systems, is intended to assist designers, manufacturers, system users and laboratories to determine the performance of stand-alone photovoltaic systems and to verify PV system design. Performance testing is conducted outdoors under prevailing conditions over a period of about one month.

Solar collectors are another type of solar power technology that can be mounted on rooftops to absorb solar energy into a usable or storable form. Such collectors are used to heat a transfer medium, which in turn supplies heat energy for hot water or space heating in residential or commercial buildings. ANSI/ASHRAE 93-2003, Methods of Testing to Determine the Thermal Performance of Solar Collectors, provides test methods for determining thermal performance of certain solar energy collectors that use single-phase fluids and have no significant internal energy storage themselves. The standard was developed by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE).

Standards from these developers and others will get a boost this year. President Bush’s 2007 fiscal year budget allotted $148 million for the nation’s Solar America Initiative. The program aims to accelerate the widespread commercialization of clean solar energy technologies by 2015. A portion of these funds will support the development of a national Solar Codes and Standards Working Group Leadership to recommend or develop model codes and standards and assist their implementation. Funding will also go toward the creation of a national voluntary photovoltaic module rating standard that will include performance, reliability and safety requirements, anticipated degradations and operational limits, as well as testing procedures and protocols.

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