Floating solar

Designed by RETTEW, the Sayreville Solar Array is one of the largest operational floating solar arrays in the nation, located in the Borough of Sayreville, NJ.  

Finding success in the fossil fuels industries, officials at Manor Township-based RETTEW decided about five years ago to dip their toes into renewable energy, specifically looking skyward to the sun.

But that interest at the engineering firm extended beyond traditional ground-mounted arrays. Instead, officials hoped to float them atop water — mimicking technology already popular in Europe.

And last year, they were part of a team that led the completion of one of the nation’s largest on-water solar power systems in Sayreville, New Jersey.

Now, the company is spearheading similar projects in other parts of the country, though none locally.

That’s all according to Jason Wert, an energy and environmental market leader at RETTEW, which employs more than 350 people within a larger four-state footprint.

According to Wert, the engineering firm was able to cement its standing within the country’s energy markets through work in Pennsylvania’s oil and gas industries — at least partially driven by the fracking boom that began in the early 2000s.

“We decided we were a little too strong within that marketplace, and we needed to diversify what we do,” Wert said.

Floating solar

That notion was the impetus for a renewable energy division within the company, which advances solar projects in addition to other green-energy work, he said, noting non-renewable work at the firm also continues.

Within that new division, RETTEW employees complete renewable design and engineering work while also overseeing construction, acting as general contractors, Wert said.

And in 2016, it was awarded a contract by officials in Sayreville, who were looking for a way to power a local water treatment plant while reducing carbon emissions.

According to a 2018 Pennsylvania Department of Environmental Protection report, traditional electricity generation accounts for about 33% of the state’s greenhouse gas emissions. And less than 1% of the state’s electricity comes from renewable energy sources.

Multiple messages, including questions about the project, left with Sayreville officials were not returned.

Floating solar, Wert said, seemed an ideal fit in Sayreville, where a total of 71 acres of still-water fills reservoirs near the wooded Julian L. Capik Nature Preserve before feeding the local treatment plant.

On that water, contractors designed and built a 12-acre floating array capable of generating 5,730,193 kilowatt-hours of electricity in its first year, according to RETTEW figures. According to the U.S. Energy Information Administration, the average household used 10,649 kilowatt-hours in 2019.

Wert offered assurances that on-water construction is thoroughly permitted, with studies needed to determine that it isn’t threatening endangered wildlife or the environment.

Completion of the $7.2 million Sayreville project was announced last October, and it produces enough energy to power 100% of the borough’s water treatment operation, Wert said.

“It’s a little more expensive than traditional solar,” he said, estimating the price is 20% to 30% higher than ground-mounted arrays.


The system is owned by New Jersey Resources Clean Energy Ventures, which deals with power to the borough.

The on-water panels create that power no differently than ground-mounted systems, Wert said.

“Aside from the fact that we are floating it on the water ... it’s really just traditional solar,” he said.

But there are benefits with using floating panels.

Installing ground-mounted solar arrays, Wert said, has sometimes meant cutting away forested area or building atop usable farmland. Floating solar provides an alternative, allowing land to be preserved, he said.

Also, water beneath the floating units keeps them cool, maximizing output, Wert said.

RETTEW officials have announced a second floating solar project in New Jersey, with construction expected to begin in 2021. Other projects also are moving forward elsewhere in the United States, but Wert said it’s too early for details to be revealed.

None are currently planned for Pennsylvania, Wert said. However, he said local employees likely will be involved in work planned elsewhere.

Speaking anecdotally, a spokesman for the Pennsylvania Public Utility Commission said he is not aware of any large-scale floating solar arrays in the state.

But by March 2021, Pennsylvania’s Alternative Energy Portfolio Standards require power companies to ensure that at least 0.5% of the state’s power is made up of solar energy, he said.

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