Firstgreen product review: Stion Ups Efficiency for CIGS Solar Panels, Plus Recent PV Performance Records
We’ve been keeping a tally of recent record-setting solar cell and module achievements. Stion, the Khosla-fundedCIGS manufacturer, just got added to the list.
Some of the following milestones represent ‘hero experiments,’ but nevertheless — the numbers keep rising. Here are some recent announcements of record-setting results:
Stion just announced a 13.4 percent module efficiency for its CIGS-based commercial modules produced at its Hattiesburg, Mississippi factory. The firm’s 145-watt module has the highest efficiency verified by NREL for a monolithically integrated CIGS module manufactured on a commercial production line, according to a release by the firm. Stion began commercial shipments from its Hattiesburg factory in the first quarter of this year. Other investors in Stion include Taiwan Semiconductor / VentureTech Alliance, Lightspeed Venture Partners, General Catalyst Partners, Braemar Energy Ventures, and AVACO.
MiaSolé has set a 15.5 percent efficiency mark for a flexible CIGS solar cell. Note that this is an aperture-area efficiency on a commercial-size flexible PV module with a total area of 1.68 square meters. That eclipses the 13.4 percent mark recently set by SoloPower. MiaSolé is targeting commercial deliveries of 14-percent-efficient glass modules by the end of the year.
MiaSolé placed third in CIGS panel production in 2011, behind Solar Frontier (at 400 megawatts) and Solibro (at 66 megawatts), according to GTM Research. The firm also recently announced a 17.3-percent-efficient champion device, while the “manufacturing process for 14 percent efficiency is now in production.” The firm recently made a rare presentation in Palo Alto, California to the Silicon Valley IEEE PV Chapter.
Heliatek set a record for organic solar cells. It’s a champion cell on a small area, but it has achieved 10.7 percent efficiency. The efficiency value for the 10.7 percent champion cell would be about 9.0 percent when deposited on a flexible substrate. The question remains: can organic solar cell technology be successfully commercialized in an unforgiving solar market dominated by crystalline silicon and First Solar? Back in late 2009, Heliatek raised $27 million to build its first factory from venture capital investors Wellington Partners, RWE Innogy Ventures, and BASF Venture Capital, as well as industrial giant Bosch.
SoloPower now boasts an NREL-measured aperture area efficiency of 13.4 percent. Module efficiency is significantly less than that. The value proposition for flexible modules from SoloPower and others is that there is less hardware required to install and the installation is easier. This thesis has yet to be proven in volume and scale. SoloPower builds flexible solar panels in a roll-to-roll electroplating process.
Suntech’s (NYSE: STP) Pluto cell technology achieved a 20.3 percent efficiency for a production cell using commercial-grade p-type silicon wafers. Pluto technology is a combination of different elements which are brought together to improve cell efficiency, with 21 percent efficiency targeted within the next year. These incremental improvements include surface patterning, improved metallization, improved front metal contact dimensions, changes in dopant concentration at the emitter, and improved high-temperature performance. None of these processes come cheap. Plus, the new product has not exactly replaced Suntech’s existing lines — it appears to remain a premium product that is offered at premium prices.
Solar Frontier is number two in thin-film solar and number one in the CIGS/CIS race, with 400 megawatts shipped in 2011. The firm just racked up a 17.8 percent aperture-area efficiency on a 30-centimeter-square CIS-based PV lab module. The result was claimed to come on a “fully integrated submodule” performed with processes “very similar to what is in place” in Solar Frontier’s factories at commercial production scale, according to a release from the firm. The Japanese firm’s Kunitomi factory recently built a champion module at 14.5 percent aperture efficiency, equivalent to a 13.3 percent module efficiency.
First Solar (NASDAQ: FSLR) hit a new world record for CdTe PV module efficiency with a 14.4 percent total area efficiency in January. That mark comes six months after First Solar hit a CdTe solar cell efficiency of 17.3 percent. Both records were set at the firm’s Perrysburg, Ohio factory.
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.
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 epitaxial wafers. Semprius recorded a module efficiency of 33.9 percent.
Abound Solar, a manufacturer of cadmium telluride PV modules, announced the production of 82.8-watt modules at its Longmont, Colorado factory, representing a 12.2 percent aperture efficiency that is now being verified by NREL. The units were produced on “existing production equipment,” according to the firm’s press release. Abound claims to have produced its millionth module in December 2011.