A Solar Innovation Could Turn Rooftops Into Moneymakers
Employees of SunEdison install photovoltaic solar panels on the roof of a Kohl’s department store in Westampton, New Jersey. (Photo: Robert Nickelsberg/Getty Images)
There are certain things you’d expect to hinder solar panels’ ability to generate electricity, such as cloudy days. But for serial technology entrepreneur Bill Gross, wind is the main adversary.
“Wind is the enemy of solar,” said Gross, noting it can blow lightweight but expensive solar panels right off the roof.
That’s not an issue when photovoltaic panels are deployed on big solar farms, as they’re anchored to the ground with heavy-duty steel and concrete. Such a solution is too heavy for residential and commercial rooftops, however, and solar panels must be either installed nearly flush to avoid catching wind or anchored at a slight angle—a design that severely limits the amount of energy the panels can capture from the sun as it moves across the sky.
Motors allow ground-mounted solar panels to track the sun, and now Gross’ California-based start-up, Edisun Microgrids, has developed technology to allow panels installed on rooftops to do the same. The result: a 30 percent boost in rooftop electricity production, the company claims. If so, that could be a game changer, accelerating the switch to renewable energy from fossil fuels.
A rendering of Edisun Microgrids' tracking solar panel system on a flat rooftop. (Photo: Edisun Microgrids)
“That’s a huge boost when you’re talking about shifting the economics on whether it is profitable or not profitable to install rooftop solar,” Gross said.
Gross expects the technology to make waves on commercial rooftops, where the solar potential of billions of square feet of space remains largely untapped.
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“In the U.S. alone, there’s roughly 50 billion square feet of flat, commercial rooftop space, and solar panels are on only 2 percent of those rooftops,” Gross said. “We see our system being suitable and economically profitable in the current energy market on about 37 percent of those roofs.”
PV Booster’s chief innovation is a patented front-mounted pivot point, which allows each panel to tilt front to back and rotate side to side while keeping a low profile—something other tracking systems haven’t been able to do. Each panel is outfitted with a low-voltage motor and microprocessors programmed to track the sun, keeping the panels flat during high winds and inclement weather.
“We’ve seen other companies try to develop something like this, but this has such a lower profile than anything else. We haven’t seen anything like it,” said Stephen Gates, founder of solar developer Neighborhood Power Corporation.
His company has installed and financed solar arrays at thousands of homes and businesses in Connecticut, Massachusetts, New Jersey, Hawaii, and the Dominican Republic and is now moving into Africa.
“Since these panels produce more energy for a longer amount of time, we can cut down on the amount of panels we have to put on a roof, and we can actually lower our carbon footprint from installations,” Gates said. “The tracking system opens up a lot more possibilities for installations—especially in the Midwest—where it didn’t make sense money-wise to install solar before.”
Gross expects the cost of a PV Booster system to be about 10 percent higher than that of a typical fixed solar rooftop system.
“Take a traditional 100-kilowatt commercial rooftop system, installed at about $3 a watt; so that’s about $300,000—around the average price right now,” he said. “So we cost 10 percent more, but we increase the power production by 30 percent. Over the course of your system, you’re paying about $270,000. That means you can pay back the cost of your solar system sooner, and you end up with a more powerful rooftop array.”
About 250 PV Booster systems are being tested at a site in Pasadena, California, near Edisun Microgrids’ headquarters. The company is unveiling the product at the Solar Power International conference in Las Vegas on Sept. 12, and Gross said the company already has orders for three megawatts of installations.
PV Booster is not Gross’ first foray into solar. He parlayed his early start-up software success into a technology incubator called Idealab. His solar ventures include eSolar, a solar farm builder that pioneered tracking technology.
“PV Booster is an apt name,” Gates said. “Fly into any airport and you’ll see the potential of those rooftops—this is an opportunity to tap that space.”
Correction: Sept. 7, 2016
An earlier version of this article attributed a quote from Stephen Gates to Bill Gross.