6 February 2012
Alta’s single-junction GaAs solar panel verified by NREL as 23.5% efficient
Alta Devices of Santa Clara, CA, USA says that its most recent solar panel has been verified by the US National Renewable Energy Laboratory (NREL) to have a solar energy conversion efficiency of 23.5%, demonstrating progress toward its objective of developing photovoltaic (PV) solutions that are competitive, without subsidies, with fossil fuels.
Founded in 2007, Alta Devices is a development-stage company focused on improving the production economics of high-efficiency solar PV applications, as well as on making breakthroughs in both manufacturing and form factor. So far the firm has received $72m in venture capital funding from investors including August Capital, Kleiner Perkins Caufield & Byers, Crosslink Capital, DAG Ventures, New Enterprise Associates (NEA), Presidio Ventures, Technology Partners, Dow Chemical, and Alberta Investment Management Corporation (AIMCo).
The latest panel uses the same technology as the firm announced last June at the 37th IEEE Photovoltaic Specialist Conference (PVSC37) in Seattle, WA, USA, which achieved record conversion efficiency for single-junction solar cells of 28.2%, resulting from technical breakthroughs in harnessing the high efficiency of gallium arsenide (GaAs) in cost–effective ways.
Alta says that it chose to focus on GaAs because of its intrinsic efficiency advantages as well as its ability to generate electricity at high temperatures and in low light. Panels hence have substantially higher energy density than other technologies, generating more kilowatt–hours of energy over the course of a year in real-life conditions.
“Our goal is to optimize the production economics of solar so that it is competitive with fossil fuels without subsidies, leading to broad adoption of solar generated electricity,” says president & CEO Christopher Norris. In addition to technology advances which push the limits of energy density, Alta is also focused on changing the manufacturing economics of solar and enabling formats and form factors that were previously not possible.
Although GaAs is known for being expensive to produce, Alta has invented a manufacturing technique that enables cells to be about 1 micron thick (a fraction of the thickness of earlier GaAs solar cells). The cell then lifts off the growth GaAs substrate (which can then be reused multiple times to amortize its high cost). In using very thin devices that have the highest energy density possible, the cost of the material needed in the panels remains low and the potential costs of an entire solar energy system based on the technology could be reduced dramatically, the firm reckons.
Moreover, because the PV film is thin and can be placed on a flexible substrate, it can be integrated in unique ways and into a variety of applications – including roof and building materials, as well as many military, consumer and transportation products, the firm claims.
According to Norris, Alta is making substantial progress on the build-out of its pilot manufacturing line, which uses mostly off–the–shelf equipment with some proprietary optimizations unique to Alta’s process. Moreover, the firm is also starting to plan for full–scale production, via activities such as building strategic manufacturing partnerships and selecting its first large, commercial manufacturing site.
“Alta has perfectly and very systematically met its plan for achieving, and then continually improving on record efficiency since the company was first funded,” comments August Capital’s Andy Rappaport.