The North Carolina Innovative Transmission Rebuild project will reconstruct the Lee-Milburnie 230 kV transmission line, incorporating advanced conductors and monopole steel structures that will enhance resilience and reliability.
The North Carolina Innovative Transmission Rebuild project will reconstruct the Lee-Milburnie 230 kV transmission line, incorporating advanced conductors and monopole steel structures that will enhance resilience and reliability.
Company Name: Duke Energy
Project Name: North Carolina Innovative Transmission Rebuild
Industry: Electric & Gas Utilities
Project Location: North Carolina, U.S.
Project Partners: Duke Energy Progress LLC; North Carolina Department of Environmental Quality; North Carolina State Energy Office
The project will upgrade and rebuild the existing Lee-Milburnie 230 kV transmission line, leveraging a climate change resilient design incorporating high-temperature, low-sag (HTLS) advanced conductors and monopole steel structures that will enhance resilience and reliability within the existing right of way. This project will bring benefits of resiliency, reliability, and jobs to the communities directly and positively impacted by this project. The project will proactively increase the regional transmission capacity to support the efficient integration of clean energy resources including solar, battery storage, and future wind generation.
The project aligns with all the Principles for Corporate Climate Resilience Leadership, but in particular, demonstrates a commitment to the principles of “Science-Based and Proactive” and “Inclusive and Equitable.” In support of “Science-Based and Proactive,” this project is informed by the Duke Energy Carolinas / Duke Energy Progress Transmission and Distribution Climate Resilience and Adaptation Report, which focuses on mitigating customer impacts from increasing storm intensity and reduced power transmission capacity caused by rising temperatures. The project supports the principle of “Inclusive and Equitable” through its impactful Community Benefits Plan that includes a commitment to Justice40 and Diversity, Equity, Inclusion, Access (DEIA) initiatives, good-paying jobs, and ongoing two-way engagement with local disadvantaged communities and universities.
Project Team: Duke Energy Progress, LLC: Office of the Project Manager; Offices of Community Benefits, Project Integration, Engineering, Permitting, and Construction
Transmission studies have shown the need to upgrade the Lee-Milburnie 230 kV line to enable the interconnection of new clean energy resources like solar, wind, and long-duration energy storage. Duke Energy is meeting this need with a transmission solution that incorporates climate change resiliency into the design, optimizes the existing right-of-way, and facilitates transmission expansion capability by allowing the addition of a second circuit in the future. The project also implements the company’s climate change adaptation framework into an actual transmission line upgrade project that can be repeated across jurisdictions and for other transmission providers.
The project has a planned in-service date of 2031 and will involve rebuilding the entire 40.18 miles of the transmission line, replacing aging assets (such as wooden H-frame poles) with new modern infrastructure and advanced conductors, incorporating switching options with future double circuit design.
The project demonstrates innovation in several ways. Monopole structures will utilize existing rights-of-way, being least disruptive to communities and avoiding any maladaptation by not requiring the establishment of new rights-of-way, which could disrupt additional ecosystems and/or affect additional communities. Monopoles require approximately one-sixteenth of the space of H-frame poles while reaching heights higher than 150 feet, allowing faster installation and shorter delivery times. The project includes the application of HTLS advanced conductors for climate change resiliency and adaptation design such that the lines are reliable and resilient through extreme weather events and facility ratings don’t materially decrease during extreme hot weather.
This project will increase energy reliability and resiliency for more than 14,000 customers—with a focus on disadvantaged communities (DACs). The climate change resilient design will reduce customer impacts associated with interruptions from aging infrastructure, hurricanes, and strong storms, with the following goals:
The design will increase the capability of the transmission line from 541 MVA (megavolt amperes) up to 1195 MVA, which will enable the interconnection of at least 1,600 MW of solar and 260 MW of battery storage by 2030. Deploying a climate change resilient design and implementation through a right-of-way optimization roadmap will allow for repeatability, sustainability, and knowledge transfer to other utilities.
Additionally, the project includes a commitment to work with North Carolina A&T University, one of the nation’s premier Historically Black College and Universities, through its STEPS4GROWTH program, and Nash Community College to provide 80 line worker pre-apprenticeships, 40 line worker certificates, and 10 craft internships–growing a much-needed workforce.