Alcoa lowers solar power costs with special coated mirrors

Joe Napsha
| Friday, March 19, 2010

Alcoa Inc. said Thursday that it has developed an aluminum-based, solar power generation system — designed, built and tested in its Upper Burrell technical center — that produces energy cheaper than solar power systems using glass mirrors.

Based on tests conducted at Alcoa Technical Center, the solar power system using the specially coated aluminum mirrors lowers the cost of generating electricity by more than 20 percent over conventional systems that use silvered glass mirrors, said Eric F. Winter, director of Alcoa's development laboratories.

The concentrated solar power system was shipped in January from Alcoa Technical Center to Colorado after Alcoa worked for about two years on designing, constructing and testing it, Winter said. About 50 people worked on the project since it began in early 2008, with a core group of about a dozen workers.

Alcoa, which has its corporate center on Pittsburgh's North Shore, developed the system in conjunction with the National Renewable Energy Laboratory in Golden, Colo., where the system is undergoing "validation tests" to determine its efficiency and structural performance. The Department of Energy gave Alcoa a $2.1 million grant to develop the project.

Test results are expected to be available this spring, and the system then would enter its next level of large-scale testing, Alcoa said.

It might take two to three years of testing before the system can be commercialized, Alcoa spokeswoman Judy Chestnutt said.

Alcoa's concentrating solar power parabolic trough consists of two aluminum mirrors, 20 feet high and 46 feet long, that reflect and focus sunlight on an oil-based fluid inside a tube connected to the hot side of a power plant. The heated fluid — reaching temperatures ranging from 600 to 700 degrees — produces steam to turn a turbine at a utility company's power plant, Winter said.

A concentrating solar power system like Alcoa's would be installed in a "solar power park," with the number of units depending on the size of the park, said Monique Hanis, a spokeswoman for the Solar Energy Industries Association, a Washington-based trade group.

A typical solar park produces enough power for 200 households annually for each 5 to 10 acres it covers.

Alcoa's project is one of about 100 utility-scale solar power projects being developed, many of which use parabolic troughs such as Alcoa's, Hanis said. Those projects use concentrating solar power technology, as well as silicon photovoltaic solar panels produced by companies such as Solar Power Industries Inc. of Rostraver.

Projects are moving toward commercialization. Federal funds in the 2009 stimulus package are helping the solar power industry to scale up faster, Hanis said.

One megawatt from a solar park can power about 200 homes.

"More than 200 megawatts of solar power will come online in 2010," Hanis said.

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