These wind turbines stripped down to the steel and completely rebuilt are forgoing the scrap heap in favor of second lives powering farms, schools and businesses.
Within the capital-intensive wind industry, there are a growing number of companies that specialize in bringing old turbines back to life, helping smaller customers save a little cash while going green.
Most of these wind turbines, once state-of-the-art, debuted on large California wind farms in the 1980s.
The Danish companies that built them took a "heavier is better" design philosophy, said Brian Kuhn of Aeronautica Windpower, based in Plymouth, Mass.
"They built themselves little battle tanks on top of the towers," said Kuhn, the company's vice president of marketing.
New 65- to 100-kilowatt wind turbines wind turbines, large enough to power a farm or help defray a school's electric bills, can cost between $3,000 and $6,000 per kilowatt, meaning the entry prices would be close to $200,000, according to American Wind Energy Association.
Buying secondhand can cut those costs by about half or even more, said Curt Eliason of Energy Maintenance Systems, another company refurbishing old turbines in Howard, S.D.
Many wind turbines are being decommissioned from some of California's oldest wind farms, having reached the end of their design lives, said Bent Kjellberg, the company's head of parts and logistics.
Some are being replaced with more powerful models, increasing the number of secondhand models on the market.
Wind farm operators are also replacing turbines more prone to kill birds along the Altamont Pass, about an hour east of San Francisco.
The turbines were sited at close intervals along the migratory path of many endangered raptors. The blades of earlier models spin faster than later generation turbines, making them more lethal to golden eagles, hawks and owls.
Some of those are winding up on the secondhand market.
Michigan's Elkton-Pigeon-Bay Port Laker School District wanted to connect a few wind turbines to its elementary building to save on energy and integrate alternative energy into its curriculum.
"We weren't looking to be an energy producer or seller," said Kathy Dickens, the junior high school's student services director. "We were really just looking to minimize our bills."
After failing to find newer models that suited the district's needs, she entered a few search terms into Google and found three Nordtank turbines from Tehachapi, Calif., that were being refurbished by enXco Inc.
The on-campus wind farm, which was fully funded through a $265,000 Michigan Public Service Commission grant and installed with volunteer labor, saves the district a little cash.
But it has provided a gold mine of educational value, as students get to study physics and electricity by building small mock-up wind turbines and competing for the top design.
"That's been the golden nugget right there," Dickens said. "We're not saving tons of money, that's for sure."