XeroCoat, Inc., a pioneering Silicon Valley startup, has entered the solar energy market with a high-performing antireflective coating for solar energy systems. Applicable across all solar energy technologies, the antireflective coating technology reportedly can increase conversion efficiency significantly and, consequently, the power output of solar systems. The technology was developed for use in high-volume, low cost photovoltaic (PV) system manufacturing.
By using the antireflective coating on a PV module, the solar energy reaching the solar cells is increased by as much as 3% at noon and by as much as 6% at early morning and evening hours. This means that solar module makers can expect a 3% increase in power output on a peak watt (Wp) basis, and a 4% increase in energy produced on a kilowatt-hour (kWhr) basis. This improvement is equivalent to increasing the efficiency of a solar cell by approximately 0.5-0.75% points, without having to modify the cell or module manufacturing process. For solar system owners, the antireflective coating increases the energy output per module, which translates to higher revenue, especially in locations with a feed-in tariff. In addition, because the peak watt per module is higher, fewer modules are needed to achieve the same total solar system watt rating, resulting in balance of system's cost savings.
For typical glass panels, depending on the time of day, 4% to 15% and more of the incoming light is lost from reflections and, thus, is not available to generate electricity. Applying an antireflective coating to the cover glass of the module will reduce these reflections and increase the module's output power. Today, anti-reflective coatings for the solar module cover glass are used in less than 5% of photovoltaic solar systems. Current commercial PV technologies convert 10%-20% of the incoming light to electricity. The same module with a suitable anti-reflective coating can deliver an additional 0.3%-0.6% power conversion. A product achieving higher conversion efficiency in a cost-effective manner can make solar modules more affordable. Delivering high performance requires that the antireflective coating reduces reflections and maximizes the solar energy available for conversion into electricity across the broadest range of wavelengths and angles possible. While multilayer coatings were the traditional solution, they add cost and reflect sunlight more than uncoated glass at certain incident angles. The combination of a single-layer optical coating and graded low-refractive index reportedly enables the new antireflective coating to achieve the highest attainable optical performance for any type of solar cover glass.
Founded by two University of Queensland, Australia researchers, XeroCoat is headquartered in Redwood City, California and maintains its research and development base in Brisbane, Queensland. The company has an international team of leading optical materials and solar energy scientists and engineers who are focused on continuous innovation of coatings for the solar energy industry. XeroCoat has just signed a contract with a large solar thermal manufacturer to provide the antireflective coating for their demonstration line. In addition, the company is actively engaged in demonstrating the technology to several leading photovoltaic module and solar thermal system manufacturers.
For more information, visit
New Antireflective Coating Increases PV Conversion Efficiency - Posted 7/20/08
July 20, 2008