The University of Maine's 9,000-pound offshore turbine prototype in Castine, Maine, has been generating power since the summer. Robert F. Bukaty/AP

Cape Wind is probably the most famous wind farm in the United States, which is especially telling because it doesn't exist. Its planned 130 turbines in Massachusetts' Nantucket Sound have been controversial enough to receive national attention — both supporting and opposing the project — ever since developers announced it in 2001. After years of legal wrangling, community protests and regulatory hoop jumping, its future is still uncertain. Cape Wind's promoters refer to it as "America's first offshore wind farm," yet not a single turbine has been erected. Meanwhile, this summer, two tugboats quietly hauled the first working offshore-wind turbine in the United States into place off the coast of Maine. Designed by the Advanced Structures and Composites Center at the University of Maine, the turbine is 65 feet high and painted bright yellow. Built 28 miles inland in Brewer, Maine, then towed down the Penobscot River, it currently floats in the blue waters off a small town called Castine, where the river meets the Atlantic Ocean. The university named its turbine VolturnUS, adapted from Vulturnus, the Roman god of the east wind, to combine the terms "volt," "turn" and "U.S." In June the university held a ceremony connecting the turbine to the U.S. power grid, with luminaries joining their voices in a sci-fi-inflected shout: "Energize, VolturnUS!" The occasion was both momentous and minor. VolturnUS is just one turbine, not 130. It's a one-eighth-scale prototype, not a 420-foot giant — "Honey, I shrunk the turbine!" the center's director, Habib Dagher, likes to joke — and it produces only enough energy to power four or five houses. Also, it will be in operation just till May, after a year of gathering data. Still, VolturnUS is a milestone in the long struggle to turn offshore wind into a significant source of energy in the United States. After decades of planning and spending and arguing, are Americans ready to start building?

Wind power's headwinds

In Europe, offshore wind energy is a fact of life. Many European countries have provided a stable policy climate for the industry for decades now, and there is broad public support. While the United States has almost 100,000 miles of coastline, it lags almost comically behind in tapping the potential of offshore wind. Offshore projects are more expensive to develop than their land-based counterparts, but they have more power potential. Offshore wind is stronger and steadier than wind that blows over land, according to the U.S. Department of Energy, because it doesn't get slowed down by mountains and valleys. So advocates tout it as new and improved: the same clean, renewable energy, a hedge against the rising costs — political as well as financial — of fossil fuels, but supersized! And since 39 percent of the U.S. population lives in counties on a shoreline, by the National Oceanic and Atmospheric Administration's count, offshore wind turbines are likely to be close to the densest population centers requiring large amounts of energy. Yet Washington's approach to offshore wind shifts almost as often as the wind itself. And since the costs are still extremely high, major investors are understandably wary. In October a large Norwegian energy company dropped its bid to build a $120 million wind pilot project off the coast of Maine after growing frustrated with the Republican governor's waffling over the project. Cape Wind is the most advanced of any large-scale offshore wind project in the United States, but it has faced more than a decade of well-publicized hurdles. Democratic Sen. Ted Kennedy famously opposed the project because it would have sullied his oceanfront views, and oil billionaire Bill Koch has devoted $5 million to the same cause in part because he says the project will raise electricity prices. Harm to birds and other wildlife is another common concern. Meanwhile, the Cape Wind team hopes to resolve a few remaining lawsuits by the end of the year. Other offshore developers "can't wait for us to get going because they know it's going to be a big help for them," said communications director Mark Rodgers, who has been working on the project since 2002. "We've got to get out there and build this stuff."

A 'floating lab'

VolturnUS owes its existence to a university-led consortium called DeepCwind, whose funders include the U.S. Department of Energy, the state of Maine and a large group of private companies, including Cianbro, PPG and Owens Corning. The consortium's goal is to install two full-size turbines off Maine's Monhegan Island in 2016 and have a full-scale wind farm in place by the 2020s. The ultimate goal is to produce 5 gigawatts of power offshore by 2030 — twice as much power as the entire state of Maine requires and the equivalent output of five nuclear power plants. Dagher estimates the project could attract $20 billion in private investment and create thousands of jobs. He likes to refer to VolturnUS as a "floating lab" and, for now, is much more interested in the data it's producing than in the small, almost symbolic amount of power flowing into the grid. Since winter winds are about twice as powerful as summer winds, the turbine is entering its real testing period. But as Russell Edgar, the university's wood-composites manager and project's operations manager, put it, "Some of the fruits of our labor won’t come to fruition for years, if not decades." Those fruits could include major advances in the most essential elements of offshore turbine design. In May of next year, about the time VolturnUS is scheduled to be towed out of the harbor, the Department of Energy will choose three offshore wind projects as recipients of an additional $46 million in funding. If the University of Maine's floating lab is among them, the school will be one step closer to building a full-scale wind farm. For now, the costs of offshore wind energy are still high — about double land-based projects', by Dagher's estimation. "We have to become cost effective or we'll never survive," he said, adding that he remains optimistic that government and community support will fall into place. "Eventually society does what's good for society," he said, expressing the kind of relentless positivism common among those invested in offshore wind energy. "We have no choice but to get there." The prototype may be small, but it's doing much of the heavy lifting needed to advance this energy solution. The result of more than five years of development, VolturnUS collects reams of data on its own performance, which will then be used to inform the design of later, full-scale models. How do the blades respond to storms? (They're designed to minimize wind resistance in dangerous gusts.) Does the floating platform stay steady in choppy waters? To test the behavior of a one-eighth scale model, Dagher's team first had to find an area with comparably small waves. A computerized wave model of the coast of Maine indicated that Castine Harbor showed promise, and measurements on site confirmed it. As Dagher put it, "This model is specific to Castine."

A turning point?