What it takes to build America's largest single-site solar manufacturing facility

At Illuminate USA’s sprawling solar-module factory in Pataskala, Ohio, the first thing you notice is that the robots have personalities.

One autonomous guided vehicle wears oversized googly eyes above its sensors. Another announces itself with a chirpy electronic rendition of the Ohio State fight song as it glides across the production floor carrying another load of material. The machines move continuously among eight production lines inside a 1.1 million-square-foot facility that Illuminate calls the largest single-site solar-module manufacturing operation in North America. 

Illuminate itself represents an unusual marriage of American energy development and global solar expertise. The company is a U.S.-majority-owned joint venture between Chicago-based Invenergy and LONGi, one of the world's largest solar manufacturers.

Illuminate USAThe scale becomes clearer as you follow one panel through the plant. Production begins with glass. A sheet slides into position beneath a laser-guided alignment system, where a transparent EVA encapsulant film is laid across its surface. Rows of photovoltaic cells are strung together and connected by wire; metal busbars tie those strings into the electrical system. Another layer of encapsulant completes what employees casually call the “solar sandwich.”

Before the module can move farther, it passes through a series of inspections. The timing matters. Once the panel enters a laminator operating at roughly 280 degrees, the cells are permanently sealed between layers of glass and encapsulant. Lamination takes about 30 minutes; curing consumes another three hours. If something inside is wrong, there is no easy repair afterward.

Junction boxes and aluminum frames come next, followed by electrical testing and a final inspection. Roughly six hours after the first sheet of glass enters the line, a finished utility-scale solar module is stacked, wrapped and prepared for shipment. The company says that choreography now repeats roughly 28,000 times a day.

That is the obvious story here: an Ohio manufacturer that began production just two and a half years ago, employing, according to the company, more than 1,600 people, and capable of producing about 5 gigawatts worth of solar modules annually.

But Kurt Wagner, Illuminate USA’s chief operating officer and its first employee, is preoccupied with something less visible.

“We have to grow into being a company that’s as mature as our annual production volume and our annual sales volume says that we are.”

That line changes the meaning of everything around it.

Building a company

Illuminate USAFactories are built in phases, while organizations are built in habits. Illuminate's physical construction happened remarkably quickly. The first production line entered service in early 2024. Within months, all eight were running. From the outside, it looked as though the difficult work had been completed.

Inside the company, leadership saw something different.

Every morning begins with the same priorities. Safety comes first. It isn't a slogan posted on a wall or recited before a shift change; Wagner and his team describe it as the foundation upon which everything else rests. Only after safety comes quality. Then efficiency. Then the equally difficult task of delivering millions of solar modules to customers exactly when they're expected.

Those priorities sound familiar because they are. Every mature manufacturer measures yield, throughput and uptime. Illuminate does, too. But the company's leaders talk less about metrics than about the routines that produce them.

That way of thinking permeates the factory. Operators monitor multiple automated stations simultaneously. Trainers circulate the floor helping employees who, in many cases, had never built a solar panel before joining Illuminate because there simply weren't many places in the United States doing this kind of work at scale. Standard operating procedures evolve continuously. Quality checks occur throughout the process because after lamination, mistakes become permanent.

"The 90% focus day to day," Wagner said, "is there's so much room to just operate what we have today better and better." The goal is to ensure panel number 28,000 is built with the same precision as panel number one.

That distinction explains why Wagner keeps returning to the same words: consistency, repeatability, stability. Startup culture often celebrates disruption. Manufacturing rewards discipline.

The building may have opened two years ago, but the company is still being built.

The factory outside the factory

For all the attention paid to domestic manufacturing, the conversation usually stops at the factory gate.

Illuminate's leadership thinks about what happens beyond it.

Every module leaving Pataskala represents dozens of upstream decisions made somewhere else. Glass manufacturers invest in new furnaces. Aluminum suppliers expand production. Solar-cell manufacturers qualify new production lines. Logistics companies build distribution networks. Each link depends on the others.

That's why Wagner repeatedly described Illuminate as the "tip of the spear" for rebuilding domestic manufacturing. The idea insists on sequencing: Illuminate built demand first, and now it needs upstream manufacturers to make their own investments in American production.

Illuminate USAA supplier doesn't spend hundreds of millions of dollars building a U.S. factory because policymakers encourage it. It does so because someone is prepared to buy enough product to justify the investment. Illuminate wants to become that customer.

Domestic solar-cell manufacturing has expanded over the past year, and new solar-glass capacity is beginning to come online as well. Illuminate last year announced a five-year agreement with SOLARCYCLE, beginning in 2028, to supply recycled solar glass produced in the United States. Company leaders describe relationships like that as evidence that a domestic supply chain is beginning to take shape—not overnight, but one investment at a time.

Today, the majority of components used to manufacture solar panels are still produced overseas, both for Illuminate and for the broader industry. While domestic suppliers are beginning to certify products and ramp production, Wagner acknowledged that a fully U.S.-sourced module would remain difficult to build at current production volumes.

That observation says as much about American manufacturing as it does about solar: Factories are visible, but supply chains are not.

The latter take longer to build because every company in the chain must solve the same problems Illuminate already has: constructing facilities, hiring workers, developing training programs, establishing quality systems and earning customers' trust.

Viewed that way, the Pataskala plant is less a destination than a starting point. The solar modules leaving the building each day are tangible evidence of domestic manufacturing returning to the United States. Less visible—but perhaps more important—is the industrial ecosystem still assembling itself around them.