ROANOKE — If wind turbines are allowed to tower up to 680 feet into the sky from a Botetourt County mountaintop, they would be higher than the tallest ones currently in the United States.
But should the county’s board of supervisors approve a request from Apex Clean Energy to build up to 22 modern windmills as tall as a 50-story building, it wouldn’t necessarily set a new record.
That’s because at least three other wind farms with even higher turbines are likely to go up before Apex completes its renewable energy project, according to Ben Hoen, a research scientist with the U.S. Wind Turbine Database.
Others, in addition to the Rocky Forge Wind Project atop North Mountain, are in the works.
“So, although these heights sound enormous (and they are undoubtedly very tall) they are not unique,” Hoen wrote in an email last week.
Green energy advocates say the latest technology allows taller turbines to more efficiently generate electricity from the wind, reducing carbon pollution from the burning of fossil fuels. Opponents counter that the bigger they are, the greater the problems with noise, shadow flicker, harm to wildlife and spoiled scenic views.
“All the negative impacts of the towers just got a whole lot worse with the 680 -foot height,” Tenney Mudge of neighboring Rockbridge County told the Botetourt County Planning Commission during a public hearing earlier this month.
The commission voted unanimously to recommend that the board of supervisors change its ordinance regulating wind farms and amend Apex’s special exception permit to allow for turbines up to 680 feet tall. When the board first granted approval in 2016, it was for 550-foot tall turbines.
A public hearing on the matter is scheduled for the supervisors’ meeting at 6 p.m. Tuesday.
Currently, the tallest operating onshore turbines in the United States stand at 654 feet at the Big Level Wind Project in Pennsylvania, according to Hoen and the American Wind Energy Association.
Apex said it has data to indicate there are 660-foot tall turbines in Missouri and North Dakota.
The average turbine built in 2019 was 494 feet tall.
“However, more and more projects are choosing taller towers and longer blades to access stronger, steadier winds and open up new areas for development, such as Virginia,” the association said in a written statement in response to questions from The Roanoke Times.
Rocky Forge would be the state’s first onshore wind farm.
The Federal Aviation Administration has approved more than 300 turbines in three projects — yet to be completed — that are higher than 680 feet, ruling that they would not be a hazard to passing aircraft, Hoen said. One is for 699-foot turbines in Illinois.
Hoen is a research scientist who leads the Lawrence Berkeley National Laboratory in maintaining the turbine database. The American Wind Energy Association and the U.S. Geological Survey also are involved in the project.
There are more than 3,000 turbines taller than 680 feet that are currently under consideration in 18 states, he said.
When Apex first proposed a wind farm in Botetourt County, elected officials welcomed the additional revenue it would bring in addition to its contribution to the green energy movement.
The board of supervisors drafted an ordinance to regulate utility-scale windmills, and in 2016 granted Apex a special exception permit that allowed it to build up to 25 turbines no higher than 550 feet.
But the Charlottesville-based company struggled to find a buyer for the approximately 75 megawatts of electricity the wind farm would produce, and an isolated 7,000-acre tract for the project north of Eagle Rock sat largely undeveloped.
Then, late last year, Dominion Energy agreed to purchase the electricity and then sell it to Virginia as part of a renewable energy package that will also include solar power. The agreement was billed as a way to help Virginia meet its goal of getting at least 30% of the electricity consumed by the state’s agencies and executive branch from renewable sources by 2022.
A few weeks later, Apex requested that Botetourt County allow the turbines to be up to 680 feet tall.
“One way that turbines have become more efficient is by getting taller and having bigger rotors; these changes allow them to collect more energy from the wind,” Apex spokeswoman Natasha Montague wrote in an email last week.
“As wind turbine technology improves, it is possible to produce more energy from a smaller number of turbines. Furthermore, these technological improvements are allowing new areas of the country to take advantage of the economic development opportunities associated with wind energy generation facilities.”
Apex told the county that it will build no more than 22 turbines at a height of up to 680 feet. But the towers may not be that tall, it says. And depending on the final height, fewer than 22 could be needed to meet its energy production goals.
In response to questions from the planning commission at its May 11 meeting, development manager Charlie Johnson said the number could range from 13 to 18 if the turbines are built 680 feet tall.
An exact number is “tough to nail down” at this point, he said.
County staff issued a report that expressed concerns about “the lack of specificity with regards to the turbines models and heights.” The planning department proposed changing the county ordinance and amending Apex’s special exception permit, but said it did not endorse the move.
Plans for the wind farm have been met with less community opposition in Botetourt than in other localities, perhaps because its location along 3.5 miles of a ridgeline is far from populated areas.
The project is backed by the Roanoke chapter of the Sierra Club, the Roanoke Valley Cool Cities Coalition, the Virginia Conservation Legacy Fund and Conservatives for Clean Energy, among other groups. Supporters outnumbered opponents by more than 2-to-1 at a board of supervisors meeting in 2016.
But with the increased heights, opposition appears to have sharpened.
Eric Claunch of Eagle Rock says an analysis by Virginians for Responsible Energy shows that the turbines would be visible from McAfee Knob in Roanoke County, a popular spot on the Appalachian Trail about 27 miles away.
“The irony is that in the interest of attempting to protect the environment, the siting of this project does the opposite, with repercussions far beyond the county,” Claunch said.
The Appalachian Trail Conservancy, however, has not opposed the project. “From my perspective, given the distance … it’s difficult for me to see how this is an A.T. issue,” said Andrew Downs, a Roanoke-based regional director of the conservancy.
Computer simulations done for Apex show the wind farm would not be highly visible in many parts of Botetourt County. Even with the taller turbines, “it’s a pretty minimal change to the eye,” Johnson said.
Although the simulations did not include areas as far away as McAfee Knob, the consultant who did the work said it was unlikely the turbines would have a visual impact on the landmark, according to Montague.
Supporters say taller turbines are needed to spur wind energy development in Virginia, where the wind is not as strong as other states that have had wind farms for decades.
A height of 680 feet is on “the tall end of the spectrum,” according to Jeroen van Dam, a principal engineer for the National Wind Technology Center, but is not unrealistic.
Apex says it hopes to complete its wind farm by the end of next year. New approvals are also needed from the FAA and the Virginia Department of Environmental Quality.
When DEQ approved the project the first time, it found that the spinning blades could be a hazard to flying bats. Apex agreed to turn the turbines off at night during the warmer months, when bats are most active.
Of all the turbines built last year, 38% ended up being smaller than their permitted height, Hoen said. Other proposed projects never got off the ground earlier, including several attempts in Southwest Virginia.
“And, again, there are a number of irons in that tall-turbines fire in the U.S.,” he wrote in an email, “so who knows what will happen in the next few years.”