Asheville - Enka Transmission Line Project
Past and expected growth in Buncombe County and the surrounding area has prompted the need for a regional transmission system enhancement. To ensure the continued reliability of the transmission system that serves this area, Duke Energy Progress plans to invest approximately $25 million to convert an existing 115-kilovolt (kV) electric transmission line to 230 kV and add a new 115-kV transmission line between the companyís Asheville Plant at Skyland and the Enka substation at 414 Sardis Road.
The project includes upgrading the existing Asheville-Enka transmission line, currently operating at 115 kV, to 230 kV. That portion of the project has been completed.
The second phase of the project includes construction of a new 7.6-mile 115-kV transmission line between the Asheville plant and the Enka 230-kV substation. That portion of the project is scheduled to be in service in late 2012 and will require acquisition of easements from some property owners.
The new transmission line will be built on 100-foot-wide property easements. Duke Energy Progress evaluated routing options between the plant and substation to determine the route that poses the least overall impact (to property owners, the environment, cultural and natural resources, etc.). The route was chosen after an evaluation process that included significant input from property owners, local governments, state and federal resource and regulatory agencies and other interested parties.
The new line, like the existing line, crosses several environmentally sensitive areas, including the French Broad River, the Pisgah National Forest, the Blue Ridge Parkway and a portion of Biltmore Company property. Portions of the new line will be closer to some existing homes and other structures than the current transmission line.
- The upgraded line and the new line and related facilities are needed to ensure that the electric system that serves the region remains reliable and continues to meet federal standards for reliability. Those standards were revised and strengthened after the major Northeast blackout of August 2003.
- The new facilities will help enhance the bulk power import capability into western North Carolina. Such capability is a critical part of ensuring a reliable electricity supply to the households and businesses that depend on us.
- Without the transmission system upgrades, this area could be exposed to extended power outages in the near future, potentially creating the types of electric system concerns that have plagued other parts of the country in recent years.
- Electricity is far too important for our customers to risk service interruptions or problems with power quality due to inadequate facilities. Duke Energy Progress has an obligation to ensure that the electric system is maintained and upgraded appropriately.
- The electric system must keep pace with growth to ensure a continuous, reliable flow of electricity to homes and businesses. Duke Energy Progress is pursuing a balanced strategy for meeting the regionís growing energy needs. The balance includes expanded energy-efficiency programs and demand-side management, investments in renewable and alternative energy technologies and state-of-the-art plants when needed. In addition to expanding load-management technologies, we must enhance the transmission and distribution systems to help ensure reliability of electricity to homes and businesses in the region. This project is one of several major transmission system upgrades under way or planned over the next several years to benefit our customers.
The project includes two main components: upgrading of the existing 115-kV line to 230 kV, which has been completed, and siting and construction of a new 115-kV transmission line.
Surveying and mapping of the selected route and initial right-of-way acquisition for the new line began in 2009. Clearing began in 2011, followed by construction of the line. The project is expected to be in service by December 2012.
The schedule and selected route are based on the best available current information. Some components of large-scale projects can change based on changes in growth and usage projections and other criteria.
Duke Energy Progress believes public participation is critical to the success of the project. Among other communication initiatives, we held a public information meeting in the area on Nov. 18, 2008. After receiving significant input from property owners, local governments, state and federal resource and regulatory agencies and other interested parties, a route was selected. The route represents the best overall choice that minimizes impacts on property owners, the environment, cultural and natural resources and other considerations. Progress Energy has notified area residents whose property is affected by the selected route.
Duke Energy Progress has acquired easements for the new transmission line from property owners. That portion of the project requires new rights of way 100 feet wide, plus rights to remove or cut back danger trees and install guy wires outside the right-of-way corridor. Right-of-way requirements in some areas might vary from the 100-foot width, depending on existing facilities or other co-location opportunities. (Danger trees are trees that could fall from outside the right of way into the line or easement, causing outages or safety concerns.)
Regulatory Approval Process
The project crosses a number of environmentally sensitive areas and will require a number of permits and regulatory approvals. Given its voltage rating (less than 161 kV), the project is exempt from a formal filing with the N.C. Utilities Commission for a certificate of public convenience and necessity. However, Duke Energy Progress will follow its standard process for ensuring significant public involvement. The project has undergone several environmental agency reviews and obtained associated permits (including erosion and sedimentation control and temporary construction storm-water permits, river crossings, etc.) and received regulatory approvals, including approval from the National Park Service for the crossing of the Blue Ridge Parkway, and from the U.S. National Forest Service for crossing the Pisgah National Forest.
Overhead vs. Underground
Duke Energy Progress investigated the possibility of putting the line underground. The reliability of underground transmission lines is a major question across the United States, as relatively few have been constructed. A fault in a buried line, caused by a manufacturing defect, an accidental dig-in or even geologic conditions, would take much longer to locate and repair than a similar fault in an overhead line. Other adverse factors regarding underground transmission lines are the effects they can have on wetlands and soil erosion and the decreased electrical capacity they can carry. Buried transmission lines can be much more disturbing of sensitive areas than overhead lines. Burying lines does not preclude the need to remove trees, and construction impacts would be considerable (with heavy construction equipment, blasting and the need to build access roads and other facilities). Mountainous terrain poses additional environmental challenges for underground lines.