The glass-and-metal building that Solyndra began erecting alongside Interstate 880 in Fremont in September 2009 was something Silicon Valley hadn't seen in years: a new factory.

It wasn't just any factory. When it was completed at an estimated cost of $733 million, including proceeds from a $535 million U.S. loan guarantee, it covered 300,000 square feet, the equivalent of five football fields. It had robots that whistled Disney tunes, spa-like showers with liquid-crystal displays of the water temperature, and glass-walled conference rooms.

"The new building is like the Taj Mahal," said John Pierce, 54, a San Jose resident who worked as a facilities manager at Solyndra.

The building, designed to make far more solar panels than Solyndra got orders for, is now shuttered, and U.S. taxpayers may be stuck with it. Solyndra filed for bankruptcy protection Sept. 6, leaving in its wake investigations by Congress and the FBI and a Republican-fueled political embarrassment for the Obama administration, which issued the loan guarantee. About 1,100 workers lost their jobs.

Amid the still-unfolding postmortems, the factory stands as emblematic of money misspent and the Field of Dreams ethos that seemed to drive the venture, said Ramesh Misra, a solar-industry analyst in Los Angeles for Brigantine Advisors.

"When you don't have the demand, you can't go into something with the attitude, 'Build it and they will come,' " Misra said. "You have to make sure the customers are already there when you build it."

He is skeptical of the company's statement, in a news release on the groundbreaking for the plant, that it had a backlog of $2 billion in orders for its cylindrical solar modules for commercial rooftops, which it touted as cheaper to install and more efficient than competing flat panels. "Backlog" is a term sometimes used loosely in the industry and may not represent firm orders at all, he said.

David Miller, a Solyndra spokesman, didn't respond to a phone call and email seeking comment.

Solyndra was the dream of founder Chris Gronet, who received a doctorate in semiconductor processing at Stanford and had spent 11 years as an executive at Applied Materials. He adopted as the company's motto, "What we do here will someday change the world." Gronet didn't return a phone call seeking comment.

Solyndra executives rushed construction in a race to fill orders, putting some work on a 24-hour, seven-day schedule. The factory was up and ready for equipment installation in 10 months. The project employed more than 3,000 union construction workers, according to a Solyndra background sheet.

"They were anticipating large production," Juancho Suntay, 51, a former Solyndra equipment maintenance technician, said in an interview. "That's why they wanted to have a state- of-the-art factory."

The plant features 19 loading docks, four electric car charging stations in the parking lot and landscaping of wild grass and a rock garden. An automated rail system moved parts through the assembly process.

Robots that resembled "a big freezer with wheels" maneuvered around the factory transporting panels from one machine to another, said George Garma, 49, a former Solyndra equipment maintenance technician from Fremont. The Disney tunes alerted workers to the robots' presence.

"It was first class," David Chan, 51, who was an information-technology contractor for Solyndra, said. "I've been in the business for 25 years and have seen some elaborate buildings. I've never seen a facility like it."

The plant caught the attention of competitors. "Everybody I know in the solar industry would remark on it and say 'Boy, that's a really, really big factory,' " said Barry Cinnamon, chief executive at Westinghouse Solar, a Campbell-based solar-panel company that manufactures in China.

"That's a lot of money that went into that factory," Cinnamon said. "It's one of those neck-snapping things every time you drove down the highway."

Commercial real-estate agents in the region wondered why a new factory was being built in the Silicon Valley region, the epicenter of some of the priciest real estate in the country, where most new construction consists of office space.

"There hasn't been a factory or warehouse building built in Silicon Valley in well over 10 years," Jeff Fredericks, managing partner at Colliers International in San Jose, said in an email.

The asking rate for industrial properties in Silicon Valley is the fourth-most-expensive in the U.S., according to Jack DePuy, Bay Area research manager at CB Richard Ellis in Foster City.

About 11.4 percent, or 950,801 square feet, of industrial space was vacant in Fremont in September 2009, according to data from Colliers.

"There was available space that we talked about with them," Bob Wasserman, Fremont's mayor, said. "It was their decision that they needed a new building. Was that a good decision? It didn't turn out to be."

John Olenchalk, senior vice president at Kidder Mathews, a commercial real-estate firm in Redwood City, said Solyndra executives considered existing space, including a former Sun Microsystems facility in nearby Newark that had 218,000 square feet of production space. The company wanted more space and to be near its existing operations, he said.

Solyndra used the new plant for the first phase of panel production. An older facility nearby finished and assembled the panels, former employees said. Problems developed at the old plant, when machinery wouldn't work properly and needed constant repair, workers said.

"Everybody was talking about it," said Edward Santos, 44, a former warehouse worker in Solyndra's logistics department.

"A significant percentage of the product we built went into a dumpster because it was defective," said Craig Ewing, 55, a former maintenance technician. "It seemed like the company accepted that," he said.