PITTSBURGH — Steelworkers tending blast furnaces and rolling mills in Pittsburgh 30 years ago could not have imagined that their jobs would turn so green, or that they would be working for foreign companies that needed their skills.

Because of the convergence of the right political and economic elements, Spain’s Gamesa Corporacion Tecnologica, among the largest wind turbine generator manufacturers worldwide, put roots down in the United States in what would seem to be the most unlikely of places — on the carcasses of Pennsylvania steel mills that were famed for their power to pollute.

Since its arrival in the state in 2004, Gamesa has become one of the drivers behind creating hundreds of unionized “green-collar” jobs and reducing carbon emissions from electrical generation. It also is part of the renewal that has been going on in Pittsburgh and its environs after the demise of the steel industry beginning the in the 1970s.

Besides being a jobs generator, Gamesa’s success in the U.S. is likely to be talked up around the world as an example of how the U.S. has been working to reduce carbon emissions with wind power.

The company, and others involved in renewable energy around Pittsburgh, also got attention last fall when the G20 nations met here. Gamesa was a Pennsylvania campaign stop for President Barack Obama to talk up renewable energy and green jobs.

Gamesa’s $200 million investment in its Pennsylvania facilities also has been held up as a template for retrofitting hulking old industrial sites into clean manufacturing facilities that are still closely linked to steel: 90 percent of the weight of a wind turbine is made of steel — or 250 tons of steel go into every turbine that goes up.

The company employs 700 workers in the state, primarily at a blade plant in Ebensburg, which is 90 minutes from Pittsburgh, and a turbine facility in Fairless Hills, near Philadelphia, on the site of an old U.S. Steel plant.

Gamesa’s growth has created green jobs at other local companies that have long histories in Pittsburgh. PPG Industries Inc., a Gamesa supplier, was founded in the 1800s as a plate-glass and paint company.

More than 100 of the company’s subcontractors are in the state and the facilities have attracted foreign investment from companies such as Hine S.A. in Spain, which makes hydraulic systems used in wind turbine generators.

“We’d like to have everyone in Pennsylvania come and work for us and be the wind energy supply center of the country,” said Michael Peck, director of external relations for Gamesa North America, whose headquarters are in Philadelphia.

It looked like that was going to happen until the economic downturn hit, curtailing orders for the giant towers and turbines as the financing for the development of wind farms tightened after a boom year in 2008.

Adding to bankers’ unwillingness to lend is the lack of regulatory certainty, both in what happens with the Copenhagen accord and in Congress with climate change legislation, which is supposed to set targets for reducing greenhouse gas and establish a cap-and-trade system for industry. Those loose ends lead to regulatory uncertainly — the bane of any growing industry.

Peck said the industry would like commitments on how much of the nation’s energy portfolio will be dedicated to renewable energy, which would create an instant market boost for wind manufacturing and installations, keeping the U.S. as the world’s largest market for production, generation and new installations.

The wind industry has been lobbying for a national renewable electricity standard of at least 25 percent by 2025. The industry argues that with the right incentives and new technology, wind power could account for 20 percent of the U.S. electrical supply in 20 years. Pennsylvania’s energy portfolio calls for the use of 18 percent of the state’s electricity to come from renewables by 2021.

“You set a floor for expectations and that’s what drives the investment," said Peck.

Overall, the industry has seen a slowdown in the growth rate of wind power installations, estimating a 20 percent rate this year compared with a 50 percent one in 2008.

The slowdown has hit Gamesa. About 150 workers in Ebensburg will be on temporary layoff or reassignment starting next month. In the meantime, the company is upgrading the facility to be ready when orders come in again. Previously, every blade made at the plant was sold.

Most of the jobs that have been created in Pennsylvania have roots in the steel industry. The United Steelworkers unionized the facilities as part of its goal to create high-paying jobs that also are environmentally sound. The fabrication of wind turbines relies on experienced machinists, welders and other skilled workers. Former coal and steel workers often fit the bill.

Rob Witherell, a representative of the Steelworkers in Pittsburgh, said when news got out that Gamesa was hiring in Ebensburg, 3,000 applicants showed up for 200 jobs.

Troy Galloway was one of the hires.

A steelworker in Johnstown who got laid off after 15 years with U.S. Steel, Galloway tried to sell real estate and started a construction company. Neither could support his family. In 2006, he landed on Gamesa’s payroll, using his machining and computer skills at the new Ebensburg facility.

“It’s a feel-good job,” said Galloway, “because you know you are doing something good for the environment.” He said he gets to see the fruits of his labor in the blades’ plant when he sees a local wind farm on his way to work everyday.

“It’s heat in the winter and air-conditioning in the summer,’ said Galloway. “You didn’t see that in the mills.”