Solar Roadways uses hexagon-shaped panels that collect energy from the sun and could be part of a smart system that changes lighting configurations to alert traffic to highway issues.
Imagine roadways that generate three times the nation's power needs, melt snow in the winter and have embedded LED lighting that can offer driver alerts and be reconfigured depending on road conditions.
That's the technology that Scott and Julie Brusaw, co-founders of Solar Roadways, are currently testing. In fact, the first prototype for their Solar Roadways project has already received federal funding.
The Sagle, Idaho-based Solar Roadways company is now running a crowdsourcing campaign on Indiegogo.com to raise more money to ramp up production of their hexagonal-shaped Solar Road Panel technology.
The hexagon panels are made up of four layers. There's a half-inch thick glass surface, followed by a layer of LED lights, an electronic support structure (circuit board) and a base layer made of recyclable materials.
The hexagon-shaped Solar Road Panels connect to make a grid (Image: Solar Roadways).
"We can produce three times more power than we use as a nation. That will eliminate the need for coal-fired power plants," Scott Brusaw said.
The polygon panels, which snap together to form circuits, can withstand up to 250,000 pounds of pressure, according to Brusaw. And while glass doesn't sound like the best material for a road, Bursaw said one of the technical specs for the panels is that it be textured to provide at least the traction offered by asphalt roads in the rain.
"We hesitate to even call it glass, as it is far from a traditional window pane. But glass is what it is, so glass is what we must call it," he said. "We sent samples of textured glass to a university civil engineering lab for traction testing... and ended up with a texture that can stop a vehicle going 80 mph in the required distance."
The Solar Roadways would have embedded LED lighting capable of creating numerous traffic patterns and signage (Image: Solar Roadways).
The panels would not only collect energy from the sun, they would be part of a "smart" system that could even talk to cloud-connected vehicles. For example, pressure sensitive monitors could detect if a moose has entered the roadway ahead and warn oncoming traffic.
Five years ago, the Federal Highway Administration funded the couple's first-ever Solar Road Panel prototype. In their second prototype of the Solar Roadway panels, the Brusaws created a beta parking lot. They foresee a time when parking lots and even athletic courts could be use the embedded LED lights to create a myriad of configurations. For example, a basketball court could be changed in an instant into a stick-ball hockey court.
The panels are made up of four layers (Image: Solar Roadways).
Brusaw believes that today's asphalt roadways, which are petroleum-based, will become too expensive in the future.
"I don't believe we're going to have the ability to build asphalt roads in 50 years. What we're proposing is a road that pays for itself over its lifespan - not only pays for itself, but provide a whole slew of new features," Brusaw said.
More than enough power?
Each solar panel produces DC power, which is converted by embedded micro-inverters into 240 volts AC.
Brusaw estimates that there are currently 31,000 square miles of asphalt and concrete surfaces exposed to the sun in the continental U.S. His company's Solar Road Panels could replace highways and byways as well as sidewalks, driveways and parking lots. "Solar road panels will collect that energy, turn the sunlight into electricity and feed the grid. If it's a business parking lot, you're feeding the building," Brusaw said.
The Solar Panels are able to resist up to 250,000 pounds (Image: Solar Roadways).
The solar cells have an 18.5% efficiency rating, the same as photovoltaic cells produced by industry-leading installers such as SunPower Corp.
By Solar Roadways own calculations, if all the hard-packed surfaces most conducive to solar collection were covered in the panels, the collective entire grid could product 13.3 trillion kilowatt-hours of energy. In comparison, in 2012, the U.S. used 3.8 trillion kilowatt-hours of electricity according to the Energy Information Administration.
The Solar Road Panels have embedded heat strips that would melt snow and ice in the winter (Image: Solar Roadways).
Brusaw, who's been visited by utility companies to discuss power grid configurations, imagines a "cable corridor" or underground conduit that would replace existing above-ground power lines.
"Currently, our prototype parking lot feeds that energy into our load center and we use the power in our building. Since the energy produced by our panels is used locally, the need for long-distance transmission lines (and their transformers) diminishes," Brusaw wrote in an email to Computerworld. "We'd slowly turn our infrastructure to a decentralized power grid, where the bulk of the power would be used close to where it is generated."
The solar panel's internal electronic connectors are hermetically sealed, Brusaw said, and external connectors would be protected in weather-proof material and filled with "an anti-corrosion gel," Brusaw said.
Embedded LED lighting in the panels would mark roadway lane divisions and other traffic indicators and a heating element in the surface (like the defrosting wire in the rear window of a car) would prevent the build up of snow/ice accumulation in northern climates. That means no more plows or road salt.
Also, because the panels are heated, there would be no damage from frost heaves.
"Roads won't experience the freeze-thaw cycle," he said. "The Federal Highway Administration contracted with us to design a road system that could pay for itself over time. State DOTs no longer have the money to maintain the current road system."
While roads get dirty, Brusaw said they discovered through experimentation, even an extremely dirty panel only produced 9% less energy than a clean panel. "And that would only be temporary - until it rained or a good wind picked up," he said.
In keeping with the Brusaws' commitment to sustainable practices, current roadways and parking lots would not be ripped up and replaced, but used as a base for the new modular panels where possible.
Interstate highways would be lit at night from beneath (Image: Solar Roadways).
Speed bumps on the road to deployment
Tom Leyden, who has worked in the solar power industry for 25 years and is currently CEO of photovoltaic battery maker Solar Grid Storage, said Solar Roadways' technology appears viable, but he questioned whether it's too costly.
"I don't think this is the cost-effective solution people are looking for at this point," Leyden said. "There are other more cost effective ways to deploy solar."
Leyden, who was formerly vice president of project development at SolarCity, one of the nation's largest solar-cell manufacturers, said the focus in the solar industry today is less on technology and more on reducing cost to capital, or beating the cost of electricity from utilities through solar panel installation.
Last year, solar power was second only to natural gas in generating new electricity in the U.S., so the market is evolving, Leyden said. Over the last decade, solar power installations averaged 66% growth annually.
"There have been many fringe ideas out there," he said. "In Europe, they looked at solar sound barriers along highways. We've considered putting solar cells in space, where you get higher efficiency. All those ideas could be doable technically, but it's a matter of how do you get these projects financed."
Brusaw argued that comparing the cost of an asphalt street to a Solar Roadway is an apples to "fruit basket" comparison.
For an accurate cost comparison between current systems and the Solar Roadways system, you'd have to combine the costs of current roads -- including snow removal, line repainting, pothole repair, etc.
You'd also have to consider power plants and the coal and nuclear material used to power them, as well as the power poles and relay stations required to transmit the power. As Brusaw notes on his website, the "Solar Roadway system... provides all three."
Solar Roadways' latest video explaining the technology.
Lucas Mearian covers consumer data storage, consumerization of IT, mobile device management, renewable energy, telematics/car tech and entertainment tech for Computerworld. Follow Lucas on Twitter at @lucasmearian or subscribe to Lucas's RSS feed. His e-mail address is firstname.lastname@example.org.
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This story, "You could one day be driving on solar-powered smart streets" was originally published by Computerworld.