It's a wonder, sometimes, that we need gas or coal at all. It seems like every day, there's a new potential source of energy out there. We know about the obvious ones -- wind and solar power. Then there are lesser known like wave energy, where people are hoping if we can harness the energy from the ocean, we might be able to create fuel cells to drive our cars.

And now the latest: traffic energy.

According to TG Daily, a technology news portal, an Israeli company called Innowattech has figured out how to collect energy from cars driving on the road. They install something called piezoelectric crystals underneath the road, and the highway vibrations are then captured by the crystals and converted into electricity. Apparently, for every kilometer (0.62 miles), you can get up to 500 kilowatts (500,000 watts), which will power approximately 100 homes.
The more cars on the road, the more electricity. These crystals are connected to an electric line running between poles, which have a device that collects and distributes electricity onto the grid.

They'll start testing their system on a stretch of highway in northern Israel in January.

According to Innowattech's web site, they could use their system not just on roads, but railways and runways, each of which would have powerful vibrations. If you're having trouble envisioning any of this, Innowattech has a brief animated video showing how this would work.

I have to admit, it sounds appealing. One of the benefits over, say, wind power is that you wouldn't need to clog up vast acreage with wind turbines, as their web site suggests, and this type of power isn't dependent on the weather in the way that solar power requires the help of the sun. On the other hand, I do think weather might play an occasional part in how traffic energy works. For instance, if it was used in the United States, and there was, say, a blizzard and suddenly no cars are on the road, would thousands of houses lose power?

That said, my guess is that a system employed like that would have safeguards -- like storing energy -- to protect from a problem like that.

In any case, it's yet another thing to watch as we travel the long road to developing green energy.

Geoff Williams is a freelance journalist and the author of C.C. Pyle's Amazing Foot Race: The True Story of the 1928 Coast-to-Coast Run Across America (Rodale).