Fear for the future amid the plenty of the present characterized the wind industry in 2011.

The US wind power business is only just getting started with 43,461 MW of installed capacity as of the end of September 2011–3.25% of the country’s electricity–and more than 8,400 MW under construction.

“The wind industry is a tremendous American success story,” said Denise Bode, CEO of the American Wind Energy Association on the release of recent industry statistics.

Although some projects continue to face regulatory uncertainty, like the Cape Wind offshore farm, because of complaints concerning noise and visual pollution, developers have been working hard to allay consumer concerns. An Australian company, Renewable Energy Solutions Australia, even designed an alternative wind-turbine with 30 blades instead of the traditional three that promises to be quieter and more efficient.

But even as it revs up, the industry is bracing for the potential of an equally abrupt slowdown at the end of 2012 when the Production Tax Credit (PTC) is due to expire. And economic troubles are making new tax incentives for renewables seem more unlikely than ever.

The world’s largest wind turbine manufacturer Vestas abandoned its forecast of €15 billion in revenues in 2015 and said that job losses and restructuring will follow instead.

Vestas cited “expected weak economic growth in the OECD area” and the potential expiry of the US Production Tax Credit (PTC) in 2013 which “could prove a very challenging year.”

Like other renewables, wind power has been extremely successful with the help of government support like the PTC. According to the American Wind Energy Association, the PTC has driven down the costs of wind energy to near grid-parity, to the point where it can compete with coal or gas-fired power plants. Wind turbines can generate electricity for less than 5 cents/kWh in many parts of the US, AWEA says.

“The industry is at a very interesting inflection point where technology and innovation are really helping to drive down the cost of wind substantially,” says Matt Kaplan, US wind analyst at IHS Emerging Energy Research. “But the problem is that the industry still needs the PTC to sustain a sizable level of build each year. Wind would have a very challenging time competing without the PTC, that much is clear.” Read more: Wind Rush: US Industry Hurdles Towards A Cliff Without Production Tax Credit.

Despite uncertainty around US incentives, the country’s wind sector still ranks third behind China and Germany in Ernst & Young’s investor attractiveness index for renewables. And the global market is booming. This June, worldwide wind capacity reached 215 GW, up from a meager 17.4 GW just a decade ago. China lead’s the world with an estimated installed capacity of 55 GW by the end of 2011 and a goal of 100 GW of wind power by 2020. See the global numbers from 2010 here.

Breaking Energy recently ran a series on the global wind market and how it has been faring this year. Read the full series here.