In 1715 the North Carolina General Assembly passed “An Act to Encourage the Building of Mills,” which granted half an acre of land to anyone who would build a windmill. The owners of these contraptions were awarded small portions of the wheat and corn crops that farmers and traders ground at the windmills. By the time the Civil War began, German-style wooden windmills dotted eastern North Carolina from the Virginia border down to Cape Fear.

Across the rural United States in the late nineteenth century, about one million families depended on small windmills to power their homes, and some six million windmills powered irrigation systems. But after Congress passed the Rural Electrification Act in 1936, utility companies began extending the electrical grid onto farms. People could wire their houses and hook into the grid. Power companies, leery of independent energy sources, made sure that their new customers destroyed the windmills. Some folks actually got out their guns and shot their wind generators.

Today the United States gets only 1.3 percent of its energy from wind power. But interest in the source is growing again as domestic oil supplies dwindle and concern about global warming spreads. Wind turbines have speckled the hills and plateaus of California and other states for many years, and in west Texas, the world’s largest wind farm came on-line in October 2009.

The United States is home to the strongest, most consistent winds on Earth, and some of them are found in coastal waters. So far, these powerful winds haven’t been harnessed to produce electricity — but that’s going to change. Several energy companies are eying the waters off North Carolina’s coast, though development is several years away.

Click to read photo caption. Map by Jesse Cleary. ©2010 Endeavors magazine.

In the realm of state policy, things are moving faster. The N.C. General Assembly passed a provision to let the University of North Carolina contract with a third party to build a pilot wind-power plant in state waters. In September 2009, UNC signed a contract with Duke Energy. The provision stipulates that up to three turbines will be installed by September 2010. If that happens, North Carolina, which lags behind many other states in alternative-energy production, will become the first state to generate wind power from in-water turbines. And if the pilot plant proves successful, the state may add more turbines, which would help North Carolina meet its stated goal of getting 12.5 percent of its power from renewable energy sources by 2021.

But first the General Assembly had to figure out where to put the turbines — if there were any suitable places at all. So the legislature asked UNC to size things up at the coast and report back. After nine months researchers handed lawmakers a 378-page coastal-wind report about everything from the likelihood of migratory birds and bats banging into turbine blades to the legal issues surrounding the creation of an in-water power plant.

On the final page of the report is a multi-colored map of eastern North Carolina overlaid with dots, circles, lines, and gray strips that look like highways connecting the Outer Banks to all points west. This messy patchwork of shapes and colors covers many areas that researchers say are off-limits for wind-power development. But offshore in federal waters there are 2,800 square miles of ocean that researchers say have great potential for wind power. And in the middle of the map — slightly northwest of Cape Hatteras in the Pamlico Sound — there’s a little green area that represents twenty-five square miles of state waters that look favorable for wind turbines. It’s too small for major development but big enough for a pilot study to show what might be possible in federal waters.

“I was surprised there was any area that looked favorable for wind turbines in state waters,” says Pete Peterson, a marine ecologist who wrote part of the report. “The waters of our sounds and coastal lakes are the winter homes of entire species of water birds. They carpet the sounds.” Throw in dozens of other ecological, geological, social, political, legal, and military concerns, and it really is a wonder that a pilot wind-power plant will be built in coastal North Carolina waters.

So, why Pamlico?

Click to read photo caption. Photo by Tore Johannesen. ©2010 Endeavors magazine.

When the N.C. General Assembly asked the state university system to conduct the study, the task fell to UNC-Chapel Hill and, in particular, to Carolyn Elfland, associate vice chancellor for campus services, who was already leading an alternative energy study to explore the use of renewable fuels on campus. “We added the coastal-wind study to that bigger energy study,” Elfland says. “I looked at the factors we were requested to study, contacted faculty researchers, and filled in gaps in the expertise available on campus with consultants already on board for the larger study.” These experts, including some she tracked down in Denmark where wind power is king, addressed issues such as wind-speed estimation, ecological and geological concerns, energy transmission infrastructure, and turbine designs.

Two of the first people Elfland called were UNC marine scientists Harvey Seim and Pete Peterson. They led research teams to figure out where winds are strong enough to warrant a wind farm and what ecological concerns could bar such a development project.

First, Seim searched for historical wind records to validate previous estimates of the wind resource in North Carolina. The State Energy Office in 2004 had purchased estimated wind-resource maps from a company called AWS Truewind. Those maps were widely used to tout the strength of North Carolina’s winds but had never been independently verified. Seim set out to do so. He and his staff worked with four undergraduates who searched for historical wind records at airports, coastal and offshore weather stations, and research installations, including Seim’s own. He also purchased historical data from Weatherflow, a firm that caters to windsurfers and that had measured winds in and around the Pamlico and Albemarle sounds.

But the historical records show wind measurements at ten meters above the surface, while wind turbines are powered by winds that reach eighty meters. So Seim had to extrapolate the historical measurements to a higher elevation. He did find some places along the coast where other people had measured winds at multiple heights simultaneously. He used these measurements to test his extrapolation techniques. He also used a device called a wind profiler to measure wind speeds vertically through a two-hundred-meter column of air. The wind profiler, stationed at the Billy Mitchell Airport on Cape Hatteras, sends very loud blips and chirps — like a Star Wars R2 unit — into the atmosphere in all directions and measures wind speeds by listening to how these frequencies shift. The profiler helped Seim create models of wind speeds at other locations.

“We wound up with three hundred years of hourly data — sixty records of five years each,” Seim says. “Our students put eyeballs on each data point to make sure the information was accurate. They weeded out anomalies such as two-hundred-mile-per-hour wind days or windless months — both are proof that a sensor was broken. We cleaned up the data set, got average wind speeds, and they wrote a report. That’s how far the students got us, which was a big help.”

He found that AWS Truewind overestimated wind speeds over land but was more accurate with its estimates at the coastline and over water. North Carolina does have some of the best wind speeds in the country, perfect for a standard 3.6-megawatt wind turbine. “I think our wind speeds are related to the presence of the Gulf Stream,” Seim says. North Carolina juts into the Atlantic Ocean and is closer to the Gulf Stream than any other state except Florida, where winds are weak partly because it’s so far from the polar jet stream. North Carolina is dominated by the Bermuda high-pressure system during summer months, which limits storms, Seim says. In winter, though, the polar jet stream plays a large role in our weather, and the North Carolina coast becomes the breeding ground for storms that batter the Northeast. “It’s those winter storms that form every five to ten days and produce a lot of wind,” Seim says.

He found that the strongest winds are offshore, over federal waters. And the best places for wind development, he says, are in Onslow Bay and Raleigh Bay, twenty miles from the coastline. In state waters the best winds are in the eastern part of the Pamlico Sound.


Meanwhile, down in Morehead City, Peterson was leading a team to study potential ecological impacts of installing wind turbines. Peterson has worked closely with many state and federal conservation and management commissions and has been studying coastal ecology for thirty years. “I thought it would be exceptionally unlikely that we could identify a place in state waters with low enough risk to pursue wind power,” he says.

Click to read photo caption. Photo by Margarite Nathe. ©2010 Endeavors.

Peterson leaned on his network of friendships and working relationships to gather information about the ecology of eastern North Carolina. He also relied on research assistant Joan Meiners and two undergraduates, who traveled throughout coastal areas to talk to experts on birds, bats, turtles, fish, butterflies, and sea mammals. They also spoke to duck hunters, ecotourism professionals, whale watchers, park service workers, academics, and fishermen.

Meiners conducted seventy interviews and came away with stacks of information. Two other undergrads were charged with finding every environmental-impact study for wind-farm development, whether on land, over water, or from other countries. Then Peterson and research associate professor Steve Fegley sorted through all of it.

As Peterson suspected, great portions of coastal estuaries and sounds are home to too many species with fragile habitats that would be disrupted or even destroyed if wind turbines were installed. But he also found that the farther you get from land and the farther east you get from the barrier islands, the less risk there is to animals — until you approach the Gulf Stream, a river of animal diversity.

“One of the things I found most interesting is the behavior of songbirds,” Peterson says. “These migratory birds typically fly higher than windmills, but they drop to lower levels during stormy weather, putting them well within range of windmills. And these birds are in great decline — bluebirds, warblers, sparrows, the birds in our backyards that we love.”

Peterson also found that insects are attracted to white windmill blades. And these insects attract bats, which have been known to chase insects toward turbines. The blades don’t always turn very fast but they do create drastic air-pressure differences in the vortices behind the turbines. And these varying pressures have caused bats to explode.

Peterson points out that some bat species eat the insects that attack our crops. “Like the bees that pollinate our crops, the bat is one of these organisms that we kind of take for granted. But we shouldn’t.”

Peterson does point to solutions: painting the turbine blades black, for instance. Also, if bats become a problem during a pilot study, researchers could attach devices to the turbines that emit ultrasonic sounds that humans wouldn’t hear but would keep bats away.

According to the impact studies from Denmark, most birds maneuver with ease between turbines or completely around wind farms. Still, Peterson says that some parts of North Carolina’s sounds are blanketed with birds during migration season. These areas — from the shoreline to two miles out — are the same places that proved to be off-limits because of fisheries.

Peterson also studied the benefits that wind turbines could bring to marine life, such as the creation of artificial oyster reefs where turbine bases would sit on the ocean floor.

There are two ways to anchor a 465-foot-tall wind turbine in water, according to the Danish firm Ramboll Wind, which was on Elfland’s project team and designed about 65 percent of the water-based turbine foundations in use around the world. One way is to place the turbine on a two-hundred-meter-wide concrete slab that sits on the ocean floor. This gravity-based system would be covered with thousands of tons of rocks that could serve as reefs for marine life. To use the gravity-based system, though, the ocean floor has to be relatively flat and very stable. North Carolina’s sounds are known to be kind of shifty. One day there’s a channel to the shoreline; the next day it’s a sandbar.

The second way to anchor a turbine foundation is to pile drive something called a monopile into the sea floor. The turbine sits on this cylindrical monopile. This system is less expensive and will be used in the Pamlico Sound pilot study.

Click to read photo caption. Image courtesy of the North Carolina State Archives.

When Elfland needed someone to figure out where wind turbines could be anchored, Peterson and Seim recommended Stanley Riggs, a geologist at East Carolina University who has spent much of his career mapping the ocean floor off the North Carolina coast and researching the geology of the Pamlico Sound. Like the other researchers, Riggs found many coastal regions ill-suited for wind-turbine installation. But large areas near the Virginia border, south of Cape Lookout, and surrounding Cape Hatteras are well-suited for wind development. One of these areas is northwest of Hatteras Island in the Pamlico Sound.

Seim says that ecological risks and ocean-bottom geology are two of the three main things that limit coastal wind-farm development. The third is military use.

“Coastal areas are very popular with the military,” he says. “They’ve lost a lot of operating space since the 1950s, and they don’t want to lose any more because it’s becoming increasingly hard to find training areas. Eastern North Carolina is one of their favorites.”

Elfland met with the U.S. Marine Corps and her team also made sure that the U.S. Navy’s training grounds were excluded from lists of possible wind-farm locations.

When all was said and done, the researchers concluded that there was one place in North Carolina waters that looked suitable for a pilot study: a twenty-five-square-mile area in the Pamlico Sound.

“We were working independently, so when we came together it was like a revelation,” Peterson says. “Where the wind is best there is also the most favorable bottom for anchoring these things. And on top of that, this area avoids most of the conflicts.”

He uses the word “most” because it’s difficult to predict every conflict. Cables will be buried under the ocean floor to run electricity from the turbines to the onshore power grid. The cables will produce an electromagnetic field. Sea turtles, among many other creatures, have internal guidance systems that depend on Earth’s natural magnetic field. Electromagnetic fields could screw up their radars and could even pose a problem for migratory fish.

“We’re concerned about that,” Peterson says. “It doesn’t seem to me that there would be a response to the buried cable. But it wouldn’t be too hard to generate those sorts of fields in the lab and have fish swim by to see if they behave normally.” And, he says, a small pilot study in the Pamlico Sound would go a long way toward addressing this concern and most others.

One thing that’s easier to measure is how a wind farm affects people. No one wants to harm the fishing or seafood industries, and the UNC study indicates that such harm can be avoided. But a lot of people also don’t want gigantic wind turbines looming over the picturesque landscape.

The pilot study will be located ten miles north of Hatteras Island and eight miles west of Avon. The turbines would be visible on the horizon but would appear to be about one inch tall. If there were subsequent wind-farm development in the prime federal-lease blocks identified by Seim, then those turbines would be about twenty miles offshore and not visible from the coast.

When Elfland, Seim, Peterson, and Riggs presented the UNC study at a public meeting in Buxton, about 250 residents filled a high school auditorium to hear them out and ask questions. A few people opposed the idea of wind turbines in the sounds. But then former UNC-Wilmington chancellor James Leutze asked for a show of hands: who preferred oil drilling and who preferred wind development? The response was quite loud. By a nine-to-one ratio, the people preferred wind.

Seim says, “We concluded that you could generate enough electricity from wind turbines off the coast to power the entire state. You’d have to put up a tremendous number of turbines, and the power grid infrastructure would need to be upgraded. But even if you developed one-sixth of the offshore region suitable for wind farms, you could generate twenty percent of the state’s power needs.”

Harvey Seim is a professor in the Department of Marine Sciences, and Pete Peterson is a distinguished professor in the Institute of Marine Sciences in Morehead City, both in the College of Arts and Sciences. Rachel Noble, who directs the Institute for the Environment Morehead City Field Site, led the group of undergraduates who conducted research as part of the institute’s Capstone Research Project. Stanley Riggs is a distinguished professor of geology at East Carolina University. The Renaissance Computing Institute used its Weather Research and Forecasting Model to make models for Seim’s work on wind-power estimation.