As Nashville grows, the infrastructure supporting it must evolve. At the intersection of Gay Street and 2nd Avenue North, Nashville Electric Service’s (NES) completed Central Substation represents a significant investment in the capacity, reliability and resilience of downtown’s electrical system.
T.W. Frierson partnered with TMP and Aubrey Silvey Enterprises in the design-build delivery of the 35,000 square foot facility for NES, replacing a substation originally constructed in 1914. Serving roughly one-third of downtown Nashville’s core business district, the new substation strengthens a critical part of the city’s electrical network while supporting continued development, including the expanding East Bank corridor.
For T.W. Frierson, the project also builds on a valued relationship with NES, bringing our team back together with a repeat client to deliver infrastructure with a lasting community impact.
High-Voltage Infrastructure Designed for Performance
At the heart of the facility are four transformers, each rated at 24/32/40/44.8 MVA and operating at 69 kV to 13.8 kV. These transformers step down incoming high-voltage electricity for distribution to downtown customers, providing increased capacity and operational flexibility compared with the legacy system.
The facility also includes 13.8 kV, 3,000-amp, arc-resistant indoor switchgear. This equipment controls and protects distribution circuits, with an arc-resistant design that enhances operator safety. Together, the transformers and switchgear support four 69-kV lines and 13 distribution circuits, creating a modern electrical backbone for the downtown core.
Coordinating a Complex Underground Network
A substantial portion of the project’s complexity sits below the surface. Extensive underground duct banks provide protected pathways for the electrical cables connecting the facility’s systems and carrying power into the surrounding network.
The project included approximately 50,000 feet of high- and medium-voltage cable, 60,000 feet of low-voltage cable and 70,000 feet of copper below ground. Installing this infrastructure required careful attention to routing, elevations, connection points and construction sequencing within a constrained downtown site.
Underground duct banks must align with equipment locations and building entry points while accommodating other buried systems. Because these pathways become difficult to access or adjust once encased in concrete and covered, coordination before installation was especially important.
The team used Virtual Design and Construction (VDC) early in the project to coordinate underground work. Modeling helped the team visualize the relationships among systems, review routing and identify potential conflicts before construction. That process provided a shared reference for coordinating the dense network below ground.
The work also included replacing aging lead cable with modern infrastructure, improving long-term reliability while reducing maintenance demands.
Building Beside Live Power
The new facility was constructed directly adjacent to the existing substation, which had to remain operational throughout construction. Maintaining electrical service to downtown customers added another layer of complexity to an already demanding project.
Site activities, underground installation and structural work required disciplined sequencing and close coordination with NES. Working near energized equipment meant safety planning and protection of existing infrastructure had to remain central to each phase.
The transition from the existing substation to the new facility required detailed planning around system connections and cutover activities, with continuity of service guiding the work.
Precision Above Ground
The project’s structural scope included 105 tons of structural steel, 342 tons of reinforcing steel and approximately 3,160 cubic yards of concrete.
The exterior brought its own technical demands. T.W. Frierson’s self-perform business unit, Design Systems Builders, LLC, installed approximately 10,000 square feet of 18-gauge perforated aluminum panels, combining straight and radius designs in a custom four-width pattern. Custom curved steel supports required precise alignment with the precast concrete elements. Additionally, our in-house overhead door company, Armory, installed the facility’s bi-fold doors which required additional coordination between the building structure, attachment details and exterior finishes.
These interfaces reinforced the value of carrying detailed coordination from the underground systems through the building envelope, including opportunities to expand model-based coordination on future projects.
Infrastructure Built on Trust
Throughout construction, the team’s approach reflected the importance of its relationship with NES. In feedback shared during the project, NES Civil & Environmental Engineering Manager Dray Moultrie recognized TWF’s commitment to quality, responsiveness and transparent communication when working through challenges.
The completed Central Substation brings that collaboration into service for Nashville. From the extensive underground network to the high-voltage equipment above it, the facility strengthens the infrastructure downtown depends on today and creates capacity for the growth ahead.
