High in the sky: BPA expands drone program to improve grid safety and reliability

Speeding along one of the Bonneville Power Administration's rights-of-way, a remote-operated drone stops over a downed tree on a transmission line. As it hovers above the damage, a BPA drone operator captures high-quality images and video from several miles away. Improving situational awareness, drone technology is helping line workers stay safe and accident-free during transmission infrastructure inspection and repair operations.

BPA's Aircraft Services team has used drones, technically known as unmanned aircraft systems, for several years to help groups across the agency with tasks ranging from vegetation management to geospatial mapping. But adding drone operators to BPA's field crews is a recent collaborative effort with Transmission Line Maintenance that began in the fall of 2024.

Peter Renggli, aircraft flight instructor for Aircraft Services, and Rob Robertsen, transmission operations and maintenance manager for Transmission Field Services, are at the forefront of the new drone program's development. Together, they have created a cross-functional team with members from their respective organizations and additional personnel from Transmission Technical Services. By November 2025, the team plans to have at least one drone operator in each of BPA's 17 transmission districts.

“It's a crawl, walk and run process," Robertsen said.

Renggli explained that the drones provide excellent visibility for close detail inspections of transmission structures. “We can't do a bottom-up assessment with a helicopter," he said. “With a drone, we are able to fly underneath a line get the perfect angle and take great photos for documentation."

The team currently has two drone operators to help review the program's work standard. Lineman Chris Warnock and lineman foreman III Andy Crosby both have prior drone piloting experience.

With drones featuring the latest technology, including high-resolution cameras, thermal imaging and zoom capabilities, Warnock and Crosby can capture crystal-clear photos and video while keeping a safe distance from BPA transmission structures, like high-voltage transmission lines.

“The high-quality zoom is huge for inspections," Warnock said. “You can zoom in and see the individual strands of wire on a conductor."

Additionally, the drone harnesses the power of AI to provide flight assistance, including collision detection and return-to-user protocols.

“If you try to fly into a structure, the drone will automatically plan a path to fly around," Warnock said. “It's safe, user-friendly and does not require a lot of skill to use."

Also, he added, if the drone loses connection to the controller or is low on battery, it will return to the launch point.

In the field, the program's two operators have already used the drones in various situations. In one instance, Crosby deployed a drone to help oversee the repair of a transmission line switch malfunction.

“I was able to record the operation of the switch and help identify what was causing the problem," he said.

While the drone's 40-minute battery life limits usage, its 40-second deployment time and 45 mph maximum flight speed dramatically shortens the time it takes for field crews to identify points of damage.

“You are flying 40 to 45 miles per hour in a straight line," Crosby said. “With that speed, you could patrol multiple miles of transmission line in just a few minutes."

Robertsen said the team is developing proper documentation and work standards for the program, which they plan to wrap up in July. By October, field crews from each transmission district will have identified two operators to attend trainings.

“We've already purchased drones and have a contract in place," Renggli said. “By November, we plan on issuing one drone to each transmission line maintenance crew." In all, the program will have 22 drones.

In the fall, future drone operators will attend trainings with an outside vendor to obtain their Part 107 commercial drone licenses. From there, BPA will provide further flight training and familiarize pilots with the agency's work standard. As the program matures, Robertsen said there are plans to explore implementation with other Transmission Field Services crafts, like power system control and maintenance operations.