A piezoelectric pad on the Shibuya subway station in Tokyo. Image © Vimeo

We’re always on the lookout for alternative energy options, especially those that are linked with big carbon producers like transportation. But unlike many of the options we’ve shared about before, piezoelectric crystals generate power from mechanical stress, and they can be installed in roads or walkways, as they already have been elsewhere in the world. Now, California is looking to take a step in the same direction with a pilot program, Laura Goldman reports for care2.com:

Energy conservation is probably not the first thing that comes to mind when you think about freeways jammed with idling vehicles.

But in California, which has some of the most congested freeways in the country, that’s about to change. The California Energy Commission (CEC) has approved a pilot program in which piezoelectric crystals will be installed on several freeways.

No, these aren’t some kind of new-agey crystals with mystical powers. Piezoelectric crystals, about the size of watch batteries, give off an electrical discharge when they’re mechanically stressed, such as when a vehicle drives over them. Multiply that by thousands of vehicles, and it creates an electric current that can be harvested to feed the grid.

In fact, scientists estimate the energy generated from piezoelectric crystals on a 10-mile stretch of freeway could provide power for the entire city of Burbank (population: over 105,000).

“I still get stopped on the street by people who ask what happened to the idea of using our roads to generate electricity,” said Mike Gatto, a Los Angeles assemblyman, in a press release announcing the program. “California is the car capital of the world, and we recycle just about everything. So why not capture the energy from road vibrations and put it to good use?”

Piezoelectric-based energy‐harvesting technology is already being used in other countries. Since 2009, all the displays in the East Japan Railway Company’s Tokyo station have been powered by people walking on the piezoelectric flooring. Italy has signed a contract that will install this technology in a portion of the Venice-to-Trieste Autostrada. Israel is already using this technology on some highways, which is how Gatto got the idea for the pilot program in California. A friend returning from a trip to Israel raved about a road that produced energy.

“If piezoelectric‐based technology has the potential to match the performance, reliability, and costs of existing or emerging renewable energy sources, then it can potentially diversify California’s resource portfolio, and ultimately increase grid reliability and reduce costs to ratepayers,” states a report prepared for the CEC in 2014 by international certification body and classification society DNV KEMA Energy & Sustainability (now known as DNV GL).

Piezoelectric technology has been used for years in electric guitars and sonar. The crystals are “in effect the reverse of sonar: a vibration comes in, and an electric pulse comes out,” according to the press release.

Read the rest of the original article here.