MIDDLESEX COUNTY, NJ — When you walk into Amazon's 1-million-square-foot fulfillment center in Carteret, it's difficult to grasp its size.

Sure, the parking lot is bigger than many. And from the outside, the warehouse certainly looks huge. But it doesn't hit you until you head upstairs, walk a path called the “green mile” and come to a balcony overlooking the first floor.

You can only see part of what's below. The rest is beneath and behind you. But, like a distant forest dense with tiny trees, the room suddenly seems huge. Instead of vegetation, though, there are yellow “pods” stuffed with items—books, Dixie plastic utensils, soap and whatever else you might want. To your left, a mountain of shelves cradles oversize inventory. Little orange robots buzz past, shuffling pods from storage to their human co-workers.

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The room goes on. And on. And on.

Pods crowd the first floor of Amazon's Carteret facility.

That's why Ali Naqvi, a senior manager for Amazon, considers that spot his favorite in the fulfillment center. It was a fitting stop for a tour featuring Rep. Frank Pallone Jr., who represents New Brunswick in Congress, and local media—which aimed yesterday, Aug. 29, to underline not only what Amazon is doing for the local economy, but also its recently opened rooftop solar farm.

And for both of those issues, size matters.

How so? For starters, Amazon's representatives said, the sprawling rooftop hosts 22,000 solar panels over 30 acres, which can generate 7.5 million watts of power. That's enough to run 600 homes or up to 80 percent of the electricity required by the facility. And all that, company officials and government leaders said, has big ramifications.

“When a company like Amazon decides to move to solar renewable,” Pallone said, “we're very happy because that lessens the amount of greenhouse gas and ultimately eliminates—or hopefully cuts back—on the problems of climate change.”

The rooftop solar farm.

Naqvi said Amazon liked the solar project because it's good for business and the environment. What's more, it makes use of space that would otherwise go unused.

The tour eventually moved to the rooftop solar farm. After climbing a tall set of construction stairs, visitors encountered row after row of the panels. In the middle stood a giant, mock, Amazon-branded light switch.

As cameras shuttered open, Pallone pushed it up. The gesture was more symbolic, as the farm went online earlier this month, according to Guy Winters, chief operating officer of Pro-Tech Energy Solutions, a company that helped launch the project.

And it took a big production to get the job done. At one point, 250 workers toiled on the roof, setting up the green energy system. In all, it took about six months, flickering on around Aug. 10, Winters said. It's due to save Amazon and partner companies money through tax credits and more, he added.

That's also good news for Amazon employees, officials said. Naqvi noted that staffers may enroll in a certification program that will enable them to care for the solar panels.

Amazon workers sign a solar panel.

The work force is another reason why size is key at Amazon.

Roughly 3,000 staffers work at the Carteret fulfillment center, the company said, boosting the local economy. They stand at the perimeter of the jungle of pods, plucking items and placing them into totes, which will eventually bring them downstairs and—after an even more robust journey—to your doorstep.

But they don't do it alone.

“At any given time,” Naqvi said, “we have about 500 robots active on the field.”

The robots are short, bright-orange rectangles. They glide across the floor, pushing pods of goods to their destination. Unchained with that extra weight, Naqvi said, the robots—called “drives” can stroll at 10 miles per hour.

Amazon said this facility is one of the largest robotics plants around. Roughly 900 drives live there. So do automated imaging machines that track inventory, and constantly shuffling conveyors.

Here, in this industrial park just off the Turnpike, the work never stops. The fulfillment center is open 24 hours per day. That's because, like the building's size and workload, Amazon's order list also appears to be never-ending.