Considering that Las Vegas streetlights are now being powered by nonstop tourist foot traffic and Hawaiian homes are consuming electricity produced by the natural sway of waves, it only makes sense that researchers in California are itching to harness clean energy from one thing that the state, for better or worse, has a whole lot of: soul-crushing freeway traffic.
While the basic technology to capture the energy produced by cars and trucks moving along, let’s say, the 5, 405, 10, 101, 280, or 580 does indeed exist, the large-scale implementation of a traffic-to-power piezoelectricity scheme has never been attempted. But as the San Francisco Chronicle reports, researchers anxious to turn California gridlock into one of the state’s top renewable energy sources are looking into it.
In fact, the Chronicle reports that the California Energy Commission recently dedicated $2.3 million in funding for two independent studies dedicated to testing the viability of large-scale clean energy projects in which California’s major roadways would be embedded with piezoelectric panels that capture the kinetic energy produced by passing vehicular traffic — the more frequent and heavier the traffic the better. The harvested energy is transformed into an electrical charge and sent to a nearby battery for storage. The stored electricity would then be used to power lighting and electronic signage along that particular stretch of road. Any excess juice would be sent back to the main power grid.
Officials estimate that in the ballpark of 400 cars and trucks per hour would need to pass over an array of tiny, asphalt-embedded electricity generators for such a scheme to be economically viable. And unlike solar and wind power — both of which rely on atmospheric conditions — traffic throughout much of California, particularly Southern California and the Bay Area, is constant, reliable.
It’s easy to surmise that Interstate 405 — one of the most congested freeways not just in Southern California but the entire nation — during rush hour (or any time of day, really) has the easy potential to be a massive energy producer. It’s lovely to imagine that the hellish, blood pressure-elevating traffic on the 405 can be transformed into a thing of good. But, of course, at the end of the day, clean energy produced by car vibrations won’t necessarily get frustrated motorists to their destination any quicker.
In addition to demonstrating a new and innovative means of clean energy production, the scheme is geared to help the California Legislature meet its goal of producing half of the state’s power from renewable sources by 2030.
“There’s a lot of traffic in California and a lot of vibration that just goes into the atmosphere as heat. We can capture that,” Mike Gravely, an electrical engineer with the California Energy Commission, tells the Chronicle. “The technology has been successfully demonstrated.”
As the Chronicle notes, within two or three years, the successes — or failures — of the two new pilot projects will give officials a better indication of whether or not harvesting power from the state’s busiest roadways is indeed viable and should be expanded.
Supported by $1.3 million in state funding, the first pilot is being conducted at the University of California, Merced where engineering professor Jian-Qiao Sun has conceived a 200-foot-long stretch of test roadway embedded with piezoelectric converters. The second $1 million pilot will be conducted in San Jose, where clean energy startup Pyro-E (winner of the Department of Energy’s 2013 National Clean Energy Business Plan Competition) will develop a piezoelectric array along a stretch of test roadway. The goal? To demonstrate that 5,000 homes could be potentially powered by the traffic moving along just a half-mile stretch of road.
The 405: Southern California's next great green power producer? (Photo: Byron Howes/flickr)
Energy-producing vibrations cause some trepidation
While plans to tap into California’s abundance of vehicular traffic as a renewable power source are generating a good amount of excitement and optimism, it’s a tough sell.
For one, skeptics worry that the cost — and potential infrastructural damage — involved with retrofitting existing roads with embedded energy converters would outweigh any economic benefits. (Both of the two, state-funded viability studies take into consideration potential road damage and whether or not piezoelectric arrays can even compete economically with other renewables.)
“The state just passed a $5 billion (per year) tax measure to fix roads, and one of the main things we want to do with pavement to keep it lasting longer and costing less is not put stuff in it that is potentially going to shorten its life,” John Harvey, a professor of civil and environmental engineering at Pavement Research Center the University of California, Davis, tells the Chronicle.
Harvey notes that roadways aren’t designed to rattle ‘n’ shake — the fact that traffic-to-energy schemes inherently rely on vibrations to produce electricity gives him pause. A car moving over a vibrating stretch of roadway could also increase fuel consumption.
And as the Associated Press wrote in September 2016, pilot projects testing the viability of similar technologies in countries such as Israeli and Italy have proven unsuccessful and been subsequently abandoned. So there's that.
"Whenever you’re talking about a new technology, there’s always a bit of skepticism,” says Mike Gatto, a California assemblyman who introduced a failed 2011 bill that proposed transforming busy stretches of road into mini-power plants. “When the hippies said you could put silicone in the desert and get a charge from the sun, people were like, ‘Right, man.’ Now there’s solar power everywhere.”
On that note, it’s worth mentioning that California is producing too much solar power. In fact, last year the state was forced to curtail — waste, essentially — over 305,000 megawatt hours of clean energy (enough to power 45,000 homes) because the state’s electric grids simply aren’t large enough to accommodate such a glut. Much like Amsterdam's too-many-bikes woes, it's an unusual and enviable problem to have but a problem nonetheless.