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InTransition Magazine : Transportation Planning, Practice & Progress

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Technical Toolbox

Here Comes the Sun-Powered Infrastructure

Solar Equipment Is Becoming More Common on the Road—One Day It May Even Be the Road

By Karl Vilacoba

About Technical Toolbox

  • Technical Toolbox highlights innovations and emerging technologies making an impact in the transportation sector.

As a childhood car nut, Scott Brusaw dreamed of a world paved with “electric roads,” often drawing highways with power-supplying slots down the middle like the popular toy racetrack sets. Brusaw never shook the idea, even after he grew up and his thoughts turned to a more grown-up issue—climate change. In 2006, the scientific curiosities of his youth and adult years were married thanks to his wife, Julie, who knew Brusaw back in his days as a kid sci-fi artist.

Scott Brusaw stands on a 12-by-12-foot

prototype of the Solar Roadway, recently

completed at his Sagle, Idaho, lab.

“One day Julie was out there gardening and she says, ‘Couldn’t you make your electric roads out of solar panels?’ And I laughed at first and thought, you couldn’t drive over a solar panel. You’d crush it,” Brusaw said. “But then we started batting the idea back and forth and thinking if you made a structurally engineered case that could withstand heavy loads and semi-trucks, you could put anything inside it—including solar cells.”

With the help of a $100,000 U.S. Department of Transportation grant, the Brusaws’ Sagle, Idaho-based company, Solar Roadways, recently completed a 12-by-12-foot prototype. It’s a small start to what they hope will one day make a significant impact on the nation’s energy policies.

From game-changing to subtle, businesses and entrepreneurs across the U.S. are developing transportation infrastructure that relies on solar power rather than the grid. Because the products are expensive, and convincing early adopters to try them can be difficult, many will never experience their moment in the sun commercially. But some inventors, like Brusaw, may see their childhood dreams come true.

Solar Roadways

So what exactly would an “electric road” do? For starters, it could lessen America’s dependence on foreign oil, help preserve the environment, revolutionize driver safety and provide a wealth of intelligent transportation systems (ITS) capabilities, according to Brusaw.

Dan Walden

This artist's rendering offers a glimpse of Solar

Roadways founders Scott and Julie Brusaw's vision

of the future--a highway system paved with solar


The Solar Roadways design has three layers—a super-hard, translucent surface; a center layer of electronics, solar cells and light-emitting diodes (LEDs); and a base plate layer that distributes power and data. The electricity generated by Solar Roadways could be fed into the grid, power nearby buildings or used to recharge electric cars. At night, LED road stripes would light up to guide motorists.

Brusaw envisions a number of “smart” functions for these roads. Electronic components might record data like traffic volume and speeds and wirelessly transmit it to services that aggregate such information to produce traffic reports. Squares in crosswalks could help alert motorists to pedestrians with pressure sensors that light up beneath their feet, not unlike the sidewalk in Michael Jackson’s “Billie Jean” video. The same concept could be applied to highways, with the lights indicating where animals recently crossed, tipping off drivers to the potential hazard ahead.

By Brusaw’s own admission, these capabilities are still a ways off. The technology is still in its early testing stages, but what he’s seen so far has been promising, and well-moneyed investors are paying attention, he said. The company believes the Solar Roadway’s best chance for achieving widespread adoption is in starting small with parking lots, driveways, playgrounds and other traditional asphalt surfaces that endure less of a pounding than a highway.

There are some obvious questions about the technology’s feasibility, but Brusaw believes there will be ways to deal with each of them. For instance, he hopes a blast-proof glass used by the military for troop transport vehicles can address durability. Heat elements embedded in the roads would have to keep them passable during snowstorms, although he said this function would consume most of the structures’ power reserves. There’s also the question that dogs even the most mainstream solar technologies—won’t this be expensive? Certainly, Brusaw said, but the cost of asphalt isn’t getting cheaper, and using it doesn’t produce any of the societal benefits Solar Roadways could.

“If we could replace all of our asphalt surfaces, we could produce more power than we consume as a nation,” Brusaw said. “We could get off of oil and coal entirely.”

Solar Trees Take Root

And while a technology like the Solar Roadways faces challenges getting off the ground, others are already firmly implanted in it. Or hanging above it.

In the fall, Dell’s headquarters in Round Rock, Texas, became the latest site to incorporate shade-providing Solar Trees in its parking lot. The Solar Trees, designed by La Jolla, Calif.-based Envision Solar International, are solar panel-lined canopies that vehicles can park beneath, protecting them from the weather and sparing drivers from the unpleasant blast of hot air when they open their car doors in the summer.

A Solar Grove at Dell's Round Rock, Texas, headquarters

provides shade for 50 cars while producing 130 kilowatts

of power annually.

The Round Rock installation provides shade for over 50 parking spaces and is estimated to produce more than 130 kilowatts of power annually, enough to spare an estimated 145,000 pounds of greenhouse gas emissions per year. The Solar Trees provide a pair of charging stations for electric vehicles and hybrids.

“The panels are up and operating as planned,” Dell spokesperson Michelle Mosmeyer said. “Employees enjoy the shaded parking, and it’s great knowing we’ve got two charging stations for employees who might want to plug in an electric vehicle. We’re excited at the possibilities that projects like this one present.”

The Solar Trees were the brainchild of Envision CEO and founder Robert Noble. In 2004, Noble, then an executive with a San Diego architecture firm, was approached by solar equipment producer Kyocera International about designing a solar carport. On its surface, the project seemed small-scale for a firm as large as the one he worked for, but Noble said the prospect “lit me up.”

In order to pose as minimal of an obstruction as possible for cars, Noble’s idea was to suspend the solar canopies on only one column—a design that reminded him of the trunk of a tree. The term Solar Tree was coined, and a family of catchy product names followed.

“I remember in a meeting, a Kyocera executive said, ‘Hey, we have 25 trees. This is a Solar Grove,’” Noble recalled. “We really had fun with it, and it was serious, too.”

Following the success and positive publicity from the Kyocera project, Noble launched Envision, which became a publicly traded company in May. Solar Groves have been built for facilities as diverse as hospitals and a McDonald’s parking lot in Pacific Beach, Calif.

Everyday Applications

The majority of solar-powered applications in transportation infrastructure today are low key and unglamorous, so much so that a driver may not notice them. Traffic signs that aren’t required to be lit at all times—for example, speed radar display signs or push-button activated crossing beacons—are becoming self-sufficient in increasing numbers, thanks to attached solar devices.

Last year, the San Francisco Municipal Transit Agency (SFMTA) launched an effort to replace 1,100 streetcar and bus shelters with new solar transit shelters by 2013. Solar equipment on the roofs power LED lights and information displays in the shelters, with any excess electricity fed into the grid.

From top to bottom, the shelters were designed with sustainability in mind—they’re built with a high percentage of recycled materials and the solar technology uses an organic dye-based film that’s more environmentally friendly to make than silicon-based solar panels, according to the city.

SolarPath Sun Solutions, of New York City, has built a global business by designing solar versions of everyday equipment. Among the company’s most popular offerings are energy-independent road signs, in-ground lights that act as brighter highway reflectors, recessed walkway lights and street lights.

Jon Robins, a market development and sales specialist for SolarPath, said “There’s very little reason to use grid-dependent lighting anymore.” A 4-6 hour charge can power a LED street light for seven days, plus they require little maintenance, no utility line hookups and stand up well to the elements. He estimated a typical fixture can last between 25 and 30 years.

With such upsides, why aren’t technologies like solar street lights more prevalent in the U.S.? According to Robins, one major sticking point is their higher upfront cost than conventional equipment. The fact that some products can pay themselves off through power savings over time doesn’t necessarily make them an easy sell to public sector customers that are under pressure to budget as little as possible each year, he said. In addition, Robins said a number of bad apple companies selling “junk” and providing poor service have hurt the industry’s reputation and caused potential customers to think twice about going solar.

There is agreement around the industry that countries like Japan and Germany—partly due to ingenuity, partly due to the economic necessity spawned by their higher energy prices—are ahead in solar technology production and use. According to a report released in April by the Solar Energy Industries Association, the U.S. increased its overall solar electric capacity by 37 percent in 2009, yet this 481 megawatts in new capacity only placed fourth in the world for the year, far behind leader Germany (3,000 MW). The U.S. (2,108 MW) also ranked fourth in cumulative solar electric capacity behind Germany (8,877 MW), Spain (3,595 MW) and Japan (2,628 MW) in 2009, and generates only 1 percent of its total energy from solar sources, according to the report.

While acknowledging that “we have to play some catch-up,” Noble is optimistic the U.S. will more strongly assert itself soon. When it does, Noble predicts the country will sift through the existing technologies, focus on what works best, discard what doesn’t, and take the products to the next level.

“I believe Americans have a creative gene. It’s sort of embedded in us, so we tend to figure these things out in the end,” Noble said.

—Karl Vilacoba is the managing editor of InTransition.

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