News

Q&A: What to expect on transmission line

By Bill Moss, Published: July 31, 2015

What is the overall plan?

Duke Energy’s Western Carolinas Modernization plan is designed to ensure an adequate supply of electricity decades into the future. Over the past 40 years electricity use in the Asheville area has more than doubled. The demand for electricity in the area is projected to grow by more than 15 percent in the next decade. To meet the need Duke plans to replace the 376-megawatt Asheville coal plant with a 650-megawatt natural gas-fired power plant at Lake Julian. Duke also says if needs to build a 40-mile transmission line from Campobello, S.C., to the Lake Julian plant to ensure adequate electricity and reliability.

What is the transmission line?

It’s the superhighway of electrical wires. The utility plans to spend $320 million to build a transmission tie station near Campobello, S.C., and the new 40-mile 230-kilovolt (kV) transmission line to the Asheville plant. “Related upgrades to transmission and substation facilities will also help overall system reliability and provide a more robust path to move power across the region,” Duke says.

How does the power company choose the route?

“The company identifies potential corridors, including existing transmission corridors, and seeks feedback from the community. A corridor is a study area that represents the potential path of a transmission line. The specific transmission routes will be much narrower and located within negotiated easements. These specific locations will be determined at a later date, following public input and further study to determine feasibility.” While the corridor is 150 feet wide, Duke notified property owners who were within 1,000 feet of the centerline. That means it’s possible, Duke spokesman Tom Williams said, that some of those landowners will not even see the transmission towers.

What do the towers look like?

“Current construction plans call for the lines to be suspended on open-framed darkened lattice steel towers. The average height of the above-ground structures will be about 140 feet, but will vary on the foothills and mountainous terrain. The conductor will be a non-reflective aluminum in order to make it less visible from a distance. Plans estimate an average of 1,000 feet between each structure.” The right of way under the lines is 150 feet wide.

Why can’t the lines be buried?

They could be but probably won’t be. Although Duke says it will look at that option, it adds that “underground transmission lines have not proven to be better than overhead transmission lines because of extremely high cost and environmental concerns.” A “fault in a buried line” would take much longer to fix. Plus, “there can be significant impacts to the environment (e.g., wetlands, trees) …”

Why can’t Duke use existing corridors?

It will for some segments. “Duke Energy will take advantage of opportunities to co-locate the planned transmission lines with existing lines where possible,” it says.

Why not use I-26?

Duke does have a smaller 100kV line running on 90-foot power poles along parts of I-26. Williams said he did not think I-26 was one of the routes. The transmission towers are 60 feet higher and the corridor is 120 feet wider than the right of way under 100kV lines.

What’s the timeframe for the transmission line?

Duke expects to choose a route later this year, survey and acquire right of way beginning next year, start construction in 2017 and complete the line by 2019.

Does my opinion matter?

Duke’s answer: “Yes, we value everyone's opinions. The energy challenges we face – and the solutions developed to meet those challenges — affect all of us. Duke Energy will use input from the public through open houses and other meetings, as well as a dedicated email WCTransmissionEnhancements@duke-energy.com and toll-free phone number (888.238.0373).” Williams added: It’s all about getting input. The maps are a few years old, we know that. If people have concerns, we want to know about them and make the best decision.”

Can farmers grow crops in the right of way?

Yes. Crops that do not reach a mature height above 12 feet (corn, tomatoes) may be planted and harvested on the right of way. “A property owner can build a fence across or along the easement, if it includes a gate at least 16 feet wide to allow Duke Energy trucks access to the easement,” the utility says. (Many older apple trees are more than 12 feet tall.)

How often will maintenance crews show up?

Not often. “Except for emergency situations, a property owner can generally expect the transmission line to be patrolled by helicopter several times a year and patrolled by foot about every five years to identify any needed repairs. Repairs that are identified during these patrols will be scheduled and completed. Trees encroaching in the right of way will be pruned at least every four years, and danger trees outside the right of way that could fall and endanger the safe and reliable operation of the transmission line will be cut, trimmed or removed as needed. Trees planted in landscaped areas within the easement that could grow to a mature height of 12 feet will be removed.”

Does the transmission line pose a health threat?

Duke says no. “Extremely low-frequency electric and magnetic fields (EMF) are all around us — not just in power lines, but also in electrical wiring in buildings, electric motors and appliances, TVs and computers. After decades of research, scientists still have not clearly identified any effects EMF exposure might have on human health.”

Can the transmission line corridor be a greenway?

“Not that I’m aware of,” Williams said. “I’ve never seen that before. We seek to buy the easement so often other people still own the property. You can grow crops that don’t go above 12 feet. You can build a fence. We don’t want to get involved in that because it’s private property.”

Will there be any more public hearings?

The N.C. Utilities Commission will hold hearings on Duke’s application for the whole project, called a certificate of public convenience and necessity. The Federal Energy Regulatory Commission will also hold hearings on the application. Given the great interest the project has generated, Duke is looking at adding more of its own public input opportunities before the end of the year.

Sources: Duke Energy, interviews.