3M and Gossamer Space Frames joined forces to continue the trailblazing path of one of the first parabolic trough installations in the United States.
In 1984, Luz International, a solar-power pioneer located in Israel, installed Solar Electric Generating System I (SEGS I) in Daggett, Calif. — one of the first successful utility-scale concentrated solar power (CSP) projects in the country. For solar power enthusiasts, a visit to Daggett is like a visit to Yankee Stadium for a baseball fan.
“It’s a historic site for those of us who work in solar,” says Dan Chen, 3M’s Business Manager for the Solar Light Management Business Unit. “The people at Luz International were innovative risk-takers, who introduced many people to utility-scale solar for the first time.”
Thanks to the efforts of 3M and Gossamer Space Frames, Daggett is now home to another solar innovation — the world’s largest parabolic trough solar collector, designed to reduce the equipment and installation costs for CSP power-generation systems. “This new collector technology could change the game for CSP,” Chen says.
The Project Partnership
3M and Gossamer have been working together since 2008, melding the materials-science technology of 3M with the parabolic-trough structural innovations of Gossamer.
“Parabolic trough installations dominate the CSP right now because of their long track record of success,” Chen says. “We had wanted to enter the CSP market for a long time, and we created our Solar Mirror Film 1100 specifically to do that.”
Glenn Reynolds, president of Gossamer Space Frames, was eager to join 3M on this project.
“We are small company, so we can easily create innovations on all of those integral systems,” Reynolds says. “But there’s a huge place for materials science — it’s what you must have for a project like this. You have to be a wizard at materials science.
“You need to be able to make a reflective film that is not only the equivalent of glass, but better,” he adds. For the Daggett project, Cogentrix Energy approached 3M as they considered adding a CSP plant to its Sunray Energy facility, the longest-operating CSP facility in the United States. 3M then reached out to Gossamer for help.
A parabolic trough works by using mirrors to focus the sun’s energy on to a heat-transfer liquid (usually an oil or a molten salt). The larger the aperture (the measurement of the trough from tip to tip), the less expensive a CSP project is to install.
The Large Aperture Trough 73 (LAT 73) featuring 3M’s Solar Mirror Film has a concentration factor of more than 100-times and an aperture-size of 24-feet (older CSP installations had troughs ranging from 10.5 to 16 feet, by way of comparison). Thanks to the film, combined with Gossamer Space Frame’s mechanical design changes, the system can reduce the installed cost of a CSP system by 25%.
The film is 50% lighter than glass and, according to the company, offers 94.5% reflectivity. The National Renewable Energy Laboratory (NREL) verified the performance of the system, measuring an optical accuracy of more than 99%.
Gossamer offers the largest commercial production solar troughs, the LAT, and is currently designing third and fourth-generation systems that it hopes will increase efficiency and lower energy production costs. Gossamer’s approach is to ensure the optimal installation of its CSP systems for maximum power generation.
The Results
Having 3M involved in the project was a must. Not only did it produce the solar film, but it put its financial stability behind it as well, which made the project more bankable.
“It doesn’t hurt when you’re talking to bankers to have the 3M name involved,” Reynolds says. “Our collaboration with them was simply amazing.”
There was no EPC in the project — 3M and Gossamer did the installation themselves. A crew of four traveled back and forth from 3M to the site and back as needed. Gossamer had its entire company working at the site — a total of 10 people.
“The same people who designed and created the system in the lab — scientists and Ph.D candidates — would go to the project site, put on their safety shoes and do some of the installation,” Chen says. “Everyone involved told us it was an energizing and interesting project on which to work.
“So often, when we’re involved in a project, we only see one piece of the puzzle,” he adds. “This was a chance for people to see their hard work on the drawing board becoming a reality.”
Reynolds says the project proves that CSP can be a viable part of the solar-energy mix in the United States for the future. Most importantly, the client was pleased.
“We’re pleased to be the first site for this technology,” says Sid Frymyer, general manager of Sunray Energy. “Developments like this demonstrate the ongoing advancements that lower the cost of solar energy within the U.S. power mix.” SPW
3M/Gossamer Parabolic Trough Vital Stats
Parabolic Trough Concentration Factor: More than 100x
Aperture Size: 7.3 meters
Reduction of Installed Cost of a Parabolic Trough Solar Field: 25%
Location of Trough: Cogentrix Energy’s Sunray energy facility, Daggett, Calif.
Materials Used: 3M Solar Mirror Film 110 and mechanical design of Gossamer Space Frames
System Measured Accuracy: 99%
Operation Start Date: October 2011
Peak Electrical Output: 275 kW
Time to Complete Installation: 3 months
Size of Sunray Energy Facility Solar Field: 400 acres
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