How we know: On-record interviews with Rosendin SVP David Lincoln and ULC Technologies' Ali Asmari in ENR, Feb. 4, 2025. Panel-rate figures from field trials are ULC's numbers. Rosendin hasn't released costs.
ConstructionCase study
A solar contractor built its own robot crew to lift 80- to 100-lb panels. Here's what the field trials showed.
Rosendin and ULC Technologies spent a year and a half developing a three-robot system, ENR reports, and it has had a year of field trials. Its SVP says the crew got smaller and the robot works. He also says the most expensive part was overbuilt.
From the archive. First reported by ENR, February 2025. Where it stands now: Unknown, as of October 2026, no current source found. Why I saved this: An electrical contractor built its own robot crew to lift 80- to 100-lb solar panels, and a time-motion study showed a four-person crew could drop to two. Its SVP also said the most expensive part was overbuilt, which is unusually candid.
February 2025 — Rosendin, an electrical contractor that builds utility-scale solar farms, put a custom robot crew on its hardest manual job: setting solar panels onto racks. ENR reported the robots are now deployed on Rosendin solar projects across the country. Here's what changed, what it cost, and what went wrong.
Cost and outcome (as of February 2025)
- Cost: Not disclosed. ENR described "a return on investment in sight" after the trials. (ENR)
- Crew: A time-motion study showed a four-person setting crew could drop to two. (ENR)
- Output, one trial (Rosendin): 350 panels in 8 hours with two operators. (ENR)
- Output, field trials (ULC): Under a minute per panel, about 60 an hour, or 600 in a 10-hour shift. (ENR)
- Old way: A traditional crew sets 100 to 120 panels per 10-hour shift. (ENR)
- Status: Deployed on Rosendin projects after a year of trials. Lincoln says Rosendin and ULC "are now working to value engineer some robot components." (ENR)
The job
Panel setting is the heavy, repetitive core of a solar build. Each panel weighs 80 to 100 lb and measures 3 by 6 feet, sometimes up to 4 by 8. Crews lift them onto racks 4 to 8 feet off the ground. A large solar farm can hold about a million of them, according to ENR. Lincoln told ENR that setting panels makes up about 25% of the labor on a solar PV project. Strains and sprains were a major safety problem.
That's a lot of lifting at sites that are often far from any city, where crews are hard to staff. So Rosendin went looking for a machine to do the lifting while electricians kept doing the skilled part.
Who built it
Rosendin didn't buy an off-the-shelf robot. It co-developed the system with ULC Technologies, a Hauppauge, N.Y., robotics firm. ENR reports "a year-and-a-half of development" and a year of successful field trials. ULC based the design on a machine it already built for utility work, its Robotic Roadworks and Excavation System, ENR reported.
How it works
The system is three tracked robots. One panel-setting robot carries a six-axis arm with a vacuum suction cup that lifts each panel from a stack onto the rack. Batteries run its electric motors, and an onboard diesel generator recharges them. Two carrier robots each hold 30 to 35 panels and shuttle them from the laydown yard, so the setter never waits for stock.
Each robot loads a KMZ file, a digital map of the site layout. It finds its position with GPS and lidar, a laser sensor that measures distance, so it knows where the next panel goes. Once the arm places a panel, human operators confirm it sits right and drive the screws. The robots won't advance until an operator confirms the panel is mounted. Every operator wears an emergency stop on the hip.
What changed
The clearest change is crew size. Rosendin's time-motion study, which clocks every step of a task, showed the setting crew could go from four people to two. In one trial, Lincoln said, two operators set 350 panels in eight hours.
ULC's Asmari gave a higher number from field trials: under a minute per panel, about 60 an hour, which works out to 600 in a 10-hour shift. That's ULC's figure from trials, not a production log. For comparison, ENR reported a traditional crew sets 100 to 120 panels in a 10-hour shift.
Why it matters
Most construction robots on the market are sold by vendors to contractors. This one runs the other way: a contractor scoped the job, co-developed the machine with ULC, and tested it on its own sites. That makes Rosendin's numbers more useful than a vendor brochure, with one catch. The company hasn't said what the robots cost, so nobody outside can check the payback yet.
What went wrong
- The drivetrain was overbuilt. ENR reports the drivetrain, the motors and tracks that move the robot, is "the most expensive sticking point" and could maybe use a more widely available option. Lincoln said: "We over-designed it a bit." Rosendin and ULC "are now working to value engineer some robot components" before wider production.
- The numbers come from trials. The 350-panel day was one trial. ULC's 600-panel estimate is a projection from its own trials. Neither is a season of production data.
- Hardening took time. ENR reported that making the multi-ton machines tough enough for rough sites, weather, puddles and slopes up to 30° took time, and remote-site power forced a battery-plus-diesel design.
- What we don't know yet: what a unit costs, how many units exist, and how they hold up over a full project.
Our follow-up question for Rosendin
After value engineering, what will one robot crew cost per panel set, counting operators, fuel and maintenance, compared with a manual crew on the same site?
Sources
- Jeff Rubenstone, “Rosendin Electric Deploys Custom Robots to Install Solar Panels,” *ENR*, Feb. 4, 2025. enr.com
© 2026 Real World Wire. Written October 25, 2026.