California probes whether special crystals could make roads generate power

Billed by one politician as "the car capitol of the world", the state of California is to put money into finding out if its clogged roads could generate electricity with the help of a special kind of crystal.

The California Energy Commission is investing $2m to study whether piezoelectric crystals embedded in asphalt could be used to produce power from the action of cars driving over them.

Piezoelectric crystals give off energy when compressed, leading supporters to see the state’s busy highways as a vast potential distributed power supply.

If it works the technology could help California reach its stated goal of generating 50% of its power with renewables by 2030.

California is the car capitol of the world, and we recycle just about everything. So why not capture the energy from road vibrations, and put it to good use?– Mike Gatto, a Los Angeles Democrat

While the technology works in other applications, the state needs to know if it could be applied to roads in a way that makes commercial sense.

November 18 is the deadline for companies or universities willing to organise field tests to submit their phase 2 applications for the funding.

Unfortunately for renewable technology enthusiasts, it appears that similar projects elsewhere in the world have not succeeded.

But the commission remains hopeful.

"It’s not hard to see the opportunity in California," Mike Gravely, the commission’s deputy division chief of energy research and development, told the Associated Press (AP). "It’s an energy that’s created but is just currently lost in vibration."

A key question is whether devices encasing the crystals could withstand endlessly being driven over.

"One would need to consider which would last longer: the pavement or the devices," Joe Mahoney, a professor of civil and environmental engineering at the University of Washington in Seattle, told AP. He noted that highways need to be resurfaced every 10 to 30 years.

The biggest champion of the project is California state assembly member, Mike Gatto, a Los Angeles Democrat who has been pushing for the adoption of the technology since 2011.

In that year he introduced a bill for two piezoelectric pilot projects but the legislation was vetoed by California Governor Jerry Brown. Gatto then pestered the Energy Commission to study the issue, and they announced the funding in July.

"I still get stopped on the street by people who ask what happened to the idea of using our roads to generate electricity," said Gatto at the time. "California is the car capitol of the world, and we recycle just about everything. So why not capture the energy from road vibrations, and put it to good use?"

Gatto claimed that engineers in Israel, Italy, and Japan had successfully installed piezoelectric generating devices in roads and railways, but AP found that two of these projects seem to have failed or been dropped.

The Israeli company, Innowattech, whose pilot test attracted global attention in 2009, is now in the process of liquidation, AP reported, adding that the Israeli roads authority said the project had been unsuccessful.

Innowattech was also planning to install crystals in a section of Italian highway but pulled out, according to Salini Impregilo, the Italian construction company involved, AP reported.

Gatto was disheartened when AP put these developments to him, but said he still believed the technology was viable.

"Hearing these details for the first time – obviously, they’re not heartening," he told AP. "I don’t want anything to be coloured by one tiny experiment by one company in a different country."

He added: "It’s probably that there are cost issues that might have been present in Israel that might not be present here."

Image: Traffic in Los Angeles, California (Prayitno/Wikimedia Commons)

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