Solyndra Fab 2 Hitting Production Targets

By SETH MASIA

Solyndra, the spanking-new, fully automated photovoltaic (PV) factory in Fremont, Calif., has hit some important production targets this year. According to a press release, the company shipped 70,000 modules in the first quarter of 2011, doubled U.S. sales in the first half and exported more than 50 percent of its production. It’s now shipping 2,000 modules a day, averaging 205 watts per module, in a factory running 24 hours a day, seven days a week, with a goal of expanding out to 200 megawatts (MW) this year and 300 MW soon. The existing buildings may eventually handle 450 MW.

Solyndra has also become a political football. A 2009 federal loan guarantee amounting to $535 million has been targeted for investigation by Rep. Fred Upton, R-Mich., chairman of the House Energy and Commerce Committee.

The White House Office of Management and Budget (OMB) in July delivered 1,400 pages of emails concerning its final review of the loan guarantee. OMB promised more documents soon.

On July 12, Upton accused the OMB of stalling, and threatened a subpoena. Upton and his staff are investigating whether Solyndra deserved that loan guarantee, and a subsequent $75 million Department of Energy (DOE) loan made after the company canceled a June 2010 initial public stock offering that was supposed to raise $300 million. The company has since raised significant new venture-capital investment.

The original loan guarantee was offered, in part, because the DOE estimated the new factory would employ 3,000 workers in construction and provide 1,000 permanent production jobs. According to David Miller, director of corporate communication at the Fremont plant, the company already employs 1,100, with 300 workers in this building on each shift, including front office and design staff. Since the factory has reached only about a third of its production potential, it would appear that it’s on track to be a significant employer, as promised. The loan guarantee backed about 74 percent of the financing to build the new plant.

An important criterion used by the DOE in this loan guarantee program was the technology’s readiness to achieve mass production quickly. Solyndra, then a start-up, applied for the guarantee in 2006 under the Bush administration. After three years of review, the deal was offered in March 2009 — the first such loan guarantee offered under the American Recovery and Reinvestment Act. Construction of the 1 million-square-foot LEED-certified building began in September 2009, and Fab 2 shipped its first product within a year. Solyndra then shut down the original Fab 1, with its 45-MW annual capacity.

Solyndra is a copper indium gallium (di)selenide (CIGS) thin-film product, with a nominal conversion efficiency of about 13 to 14 percent. The 7,000 panels on the factory roof produce 1.23 MW to power the office space, about 25 percent of the building’s current load. That works out to 175 watts per panel, but Miller points out that the array includes a lot of early production and quality-challenged modules. “If we were to do the same system for a customer it would be about 5,000 panels,” he said. That would be 246 watts per panel, close to the company’s goal of 250 watts in the near future. The best panels going out right now test out at 220 watts.

Each tube is a multi-layer concentric assembly. The CIGS tube is of tempered glass, progressively coated with copper, indium and gallium selenide. It’s scribed in a helical pattern, and then scribed again along its length to divide the CIGS layers into 200 cells. Inside that tube is a long, thin Mylar gas bag to compensate for thermal expansion of the helium atmosphere inside the finished tube. The CIGS tube in turn is contained in an acrylic plastic tube, and the entire assembly is protected by another external tempered glass tube. A clear oily fluid sits between the acrylic and outer tubes to help refract light around the cell cylinder, and the ends are hermetically capped in much the way a fluorescent tube is sealed. One end becomes an anode, the other a cathode. So the wiring harness built into one rubber-coated structural side rail delivers a positive charge, the other negative.

If you were to roll the CIGS area out flat, it would measure 467 square centimeters. That multiplies to about 1.87 square meters for a panel. Because only half the tube faces the sun, Solyndra’s literature claims 1 square meter of equivalent PV surface. But to get the claimed power output at 14 percent efficiency, it’s clear that photons are also harvested on the underside of the panel, from backscatter off a high-albedo roof.

The assembly line is fully automated. One of the first workers I encountered on a tour July 11 was a squat, cubic delivery robot, autonomously carrying a pallet of material from the loading dock. This rubber-tired hod carrier broadcast the theme from Raiders of the Lost Ark in place of its original warning beeper, which human employees had found annoying.

Once loaded into the front end of the production line, the tubes are never again touched by human hands. All inspection, cleaning, coating, scribing, assembly, sealing and testing processes are handled with linear equipment. Stationary robots handle transfers between conveyor lines, just as happens in a highly automated flat panel factory. Human supervisors handle workstations monitoring several processes at once, with video close-ups of critical steps. A big difference: no screen printing or soldering stations.

The lines are set up to run 24/7 for three weeks at a time, and then pause for a rapid maintenance break. Miller likens the pause to a pit stop. When everything runs as designed, a stack of 40 tubes moves through the line from receiving dock to shipping dock in 24 hours.

Solyndra pitches a unique product, promising rapid, nearly tool-free installation and light footprint. Each 60-pound Solyndra “panel” is a 1-meter-by-2-meter collection of 40 tubes, designed to stand about a foot off a flat white roof. Because the wind goes through the open grid, Solyndra claims stability to 130 mph (210 kph) when the modules stand on their own snap-in-place feet. Add ballast or tethers, and wind safety goes to 180 mph (290 kph). Snow falls straight through the grid, and an array adds 2.8 pounds per square foot (13.7 kg per square meter) to roof loading. Panels are easily unsnapped and moved for roof maintenance or to accommodate new rooftop equipment. Because the sun always faces a convex surface, Miller says, the daily power curve is broader and flatter than that of a non-tracking flat panel.

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