SUNBURY -- Inside Penn Wind LLC's main conference room, where workers with open laptops get down to the serious business of wind energy, dozens of purple and white thumbtacks dot a map of Pennsylvania.

The purple tacks stand for sites Penn Wind is actively pursuing, white for ones it has tested and found lacking. In the broadest sense, they mark the future of the United States. In the next-best-thing foot race of a newly thriving industry, they're a telling symbol for how quickly wind energy has arrived.

Finding a suitable site for a wind farm is not as easy as holding a finger aloft to check for a steady breeze.

According to ActionPa.org statistics, there are 10 wind farms operational in the state, with four more, including one in Northumberland County, under construction.

While electric prices have spurred great interest in the search for alternative energy sources nationwide, industry and state regulators said there are no proposals for other wind farms in the Central Susquehanna Valley.

Still, by the end of this year, Pennsylvania will be producing nearly 500 megawatts of wind energy annually, enough in theory to power almost 10 percent of the state's homes, said Thurman Brendlinger, a spokesman for the Pennsylvania Clean Air Council.

Justin Dunkelberger, CEO of Penn Wind, opened his office on Market Street in Sunbury in 2006. Since then, his company has researched and acquired, through a lease, 200 acres of turbine-ready land in East Cameron Township, Northumberland County.

He plans to have as many as nine turbines online there by 2009, and will soon thereafter begin recouping cash on Penn Wind's $36 million initial investment. At full capacity, the site will have enough juice to power a city the size of Shamokin, Dunkelberger says. Penn Wind will sell the energy it produces likely to PPL.

By comparison, the coal-fired power plant in Washingtonville produces enough energy for 1 million homes, according to the utility.

The government has given renewable energy producers like Penn Wind a nice meal ticket: By 2010, all Pennsylvania utilities will be required to get 8 percent of their energy from renewable sources. According to PPL spokesman George Lewis, that means plenty of business for Dunkelberger and other ground-floor wind energy start-ups.

"We're putting at least $100 million into renewable energy projects over the next five years," Lewis said of PPL's investment. Over the next two years, commonwealth utilities like PPL will be scrambling to grab as much renewable energy as they can.

Pa. No. 2 in East

The commonwealth, Brendlinger says, ranks second in the East in wind energy, behind only New York.

"Pennsylvania is doing quite well with the development of wind," he said. "Looking at the big picture, wind is essential, especially in Pennsylvania, where there are lots of electric users."

But while the commonwealth may look good in its wind power production in the East, Dunkelberger says Pennsylvania lags behind in comparison to its neighbors out West.