#record efficiencies

Despite dark times, record photovoltaic module performance across all materials systems, from CdTe to c-Si to CPV to CIGS to GaAs

Eric Wesoff: February 7, 2012

While the recent solar market has its dark side (bankruptcies, layoffs, slim profits, and consolidation), the industry continues to innovate and drive device performance ever upward.

That means that when the solar sector makes it through these lean times, it will possess increasingly higher efficiencies and even lower price-per-watt metrics than today's already surprisingly low numbers. These performance records are occurring across the board in every photovoltaic materials system, from CdTe (Abound) to CIGS (MiaSolé) to GaAs (Alta Devices) to triple-junction CPV cells (Solar Junction and Semprius) to crystalline silicon (SunPower). Here are some recent announcements of record-setting results: Alta Devices' most recent gallium arsenide (GaAs)-based solar panel boasts a 23.5-percent efficiency, as verified by the National Renewable Energy Laboratory (NREL). The firm claims that "This is the highest solar panel efficiency yet achieved." The press release did not discuss the size of the panel and the company has not yet responded to our inquiry. Alta Devices has won more than $120 million in venture funding from August Capital, Kleiner Perkins Caufield and Byers, Crosslink Capital, DAG Ventures, NEA, Presidio Ventures, Technology Partners, Dow Chemical, AIMCo, Good Energies, Energy Technology Ventures, and Constellation Energy. The firm is still in the pilot manufacturing phase. Chris Norris, the CEO of Alta, has said that the company's goal is to "compete with fossil fuels without government subsidies" and get to a levelized cost of energy of $0.06 to $0.07 per kilowatt-hour. The epitaxial lift-off technique pioneered by Alta founder Eli Yablonovitch allows the firm to produce layers of GaAs that are flexible and measure only one micron in thickness.

SunPower has been the heavyweight champion of the world when it comes to commercialized cell and module efficiencies for the last half-decade -- and by a significant measure. The company's back-contact crystalline silicon cell design, in commercial production since 2005, moves the metal contacts to the back of the wafer, maximizes the working cell area, and eliminates redundant wires. SunPower has been able to achieve consistent improvements in efficiency with each successive generation of commercialized cells, and this has translated to gains in the module arena, as well. The firm's Gen 3 cells have efficiencies in excess of 23 percent.

MiaSolé, a CIGS thin film PV manufacturing startup, placed third in CIGS panel production in 2011 behind Solar Frontier (at 577 megawatts) and Solibro (at 95 megawatts), according to GTM Research. The firm just announced a 17.3-percent-efficient champion device, while the "manufacturing process for 14 percent efficiency is now in production," according to the firm. The firm is making a rare presentation on Wednesday night in Palo Alto, California to the Silicon Valley IEEE PV Chapter.

Solar Junction, a developer of multi-junction cells for high-concentration photovoltaic (HCPV) applications, is working with Semprius and has inked an agreement to deliver multi-megawatts of cells epitaxial wafers. Semprius claims to have set the world-record CPV solar module efficiency using Solar Junction's III-V multi-junction solar cells based on lattice-matched dilute nitrides. The firm recorded a module efficiency of 33.9 percent.