A Path for Power

Cumberland Switchyard: Future of the Grid

TVA’s new 500‑kilovolt indoor switchyard is clean, ordered, almost cathedral‑like. If you didn’t know better, you might think you’d walked into an industrial art museum.

But it’s actually a switchyard site in Cumberland City, Tennessee. One of the most advanced switching facilities in the region, this place was built to handle tremendous power with intricate precision.

“It’s unlike anything TVA has ever done at this scale,” said Jason Huffine, senior project engineer. “And it’s a sign of where the grid is going.”

That future – more resilient, more flexible, more weather-proof – starts in rooms like this.

A switchyard is, at its core, a routing center for electricity.

“Think of it like routing trains,” Huffine said. “You align the path, you stop something when you need to, and you redirect when the system calls for it. It’s about sequencing power so it moves safely.”

Most of the time, switchyards live outdoors, exposed to the elements. But this design brings the entire system indoors, protecting vital equipment from storms, lightning and heatwaves.

Perhaps the most innovative part of Cumberland’s new switchyard is that it implements gas-insulated switchgear (GIS), a system that carries high voltages through sealed metal enclosures filled with inert, nonflammable gas. That gas provides strong insulation and suppresses electrical arcs so that equipment can be closer and more compact – a feature that has kept this project within a very small footprint.

The indoor environment also enhances worker safety. Field crews often troubleshoot problems in extreme weather – the same conditions that can cause outages. Housing key equipment indoors removes many of those risks.

“When everything is stable, our work becomes safer,” Huffine said. “You’re not worrying about what’s blowing in, icing over or heating up.”

For switchyards, it’s about sequencing power so that it moves safely and efficiently. That sequencing supports the grid beyond the switchyard’s walls – because as the Valley region grows, power demands grow with it. 

And this switchyard model addresses those needs directly. The engineers built the structure with future expansion in mind, giving TVA the ability to integrate additional transmission lines and generation sources as the region continues to grow.

“This design is about staying ahead,” Huffine said. “We’re not waiting for equipment to wear down or weather to disrupt us. We’re building for what the system will need 10 and 20 years from now.”

Integration manager Jarrad Jones plays a key role in ensuring that installed components meet TVA’s operational and quality standards.

“My role is really about making sure everything we receive transitions seamlessly into energized, operational assets,” Jones said. “What stood out to me was how closely Engineering, Procurement and Construction (EPC) methods align with TVA’s own processes. They bring a fresh perspective that helps us benchmark, refine and continuously improve.”

Projects of this scale are essential to TVA’s ability to grow efficiently.

“Our internal workforce alone cannot meet the region’s accelerating infrastructure needs," Jones said. “By partnering with an experienced EPC team, we can expand capacity while keeping reliability high and allowing TVA teams to stay focused on mission-critical responsibilities.”

For those supporting the project on the ground, the experience has been equally transformational.

Andy Simpson, who brings more than 25 years of substation construction expertise, has helped guide on‑site challenges throughout the build.

“What surprised me most was the willingness of everyone – from upper-level management to the crews in the switchyard – to stay open‑minded to new ideas and solutions,” Simpson said. “I learned a lot of new and different ways of constructing substations that I’ll carry forward to help make TVA even more successful.”

Simpson said the project reinforces TVA’s long-term vision for reliability and innovation.

“Projects like this strengthen TVA’s dedication to improvements that support every community we serve – and the Bulk Electric System that provides stability for the entire United States,” he said. “I’m proud to be part of that mission.”

To help meet the region's growing power demand, TVA has more than 6,200 megawatts of new generation planned and about 3,770 of these megawatts under construction. This includes 1,450 megawatts under construction at Cumberland Combined Cycle Plant, which the switchyard will help serve. Additionally, the TVA Board also recently announced steps to continue operations at Kingston and Cumberland fossil plants, which will enable operation of those units beyond their current retirement dates, pending future permitting activities.

As more communities grow, as extreme weather becomes more frequent and as reliability becomes even more essential, TVA is investing in infrastructure built not just to last – but to lead.