Potential in kinetic energy capture
Washington - Amid a search for greener and sustainable energy, one US company is introducing a way to capture energy from rolling cars and trucks which is otherwise wasted, to generate electricity.
Although the notion of "harvesting" kinetic energy is not new, the "rumble strip" devices by Maryland-based New Energy Technologies appear to be among the the first coming to the market offering a way to generate energy from moving vehicles.
"We take some of that rolling resistance and capture it and convert it to electricity," company chief executive John Conklin told AFP.
The firm previewed its MotionPower strips at the civic centre in Roanoke, Virginia.
As drivers slowed down, or came to a stop, their vehicle tires depressed small rumble strip-like treadles, allowing for the capture of kinetic energy.
This captured energy was converted to electricity, which powered a series of brightly illuminated lights displayed to drivers.
Because the amounts of electricity generated are relatively small, the best use would be in areas where the electricity can be used locally instead of transmitting over a distance.
Conklin said this type of system has tremendous potential in high-traffic areas, such as sports venues, shopping malls, and toll and border crossings, to power lighting and other electrical systems.
"We know there are 150 million registered vehicles that travel six billion miles a day in the United States - that's a tremendous amount of kinetic energy," he said, adding that the firm has developed its own technology without any government support.
"Our goal and approach is to design and deploy this at a cost-competitive payback," which would be more cost-effective than using solar panels, he said.
Scientists have long seen a potential for harvesting kinetic energy using such methods, but the applications have been limited.
Mechanical engineering professor Lei Zuo and colleagues at Stony Brook University note in a research paper that only 10 to 16% of the fuel consumed by cars is used to drive the vehicle and much of the energy is wasted, and describes the potential for harvesting energy through a regenerative shock absorber. Others have captured energy from braking systems.
City College of New York researchers led by Yiannis Andreopoulos see potential in road-embedded piezoelectric systems - using pressure from cars to squeeze crystals that generate electricity - which have been used in Israel among other places.
"In general is quite feasible to tap on energy which otherwise goes wasted," Andreopoulos told AFP, although he added he was not familiar with the New Energy system.
"Technically the main problem is the efficiency in the conversion of kinetic energy of the vehicle to electrical charge... There is no fuel cost involved and the only parameter to consider is the initial cost and the time to break even beyond maintenance and reliability."
Andreopoulos said any power generated from such systems would be "incremental" but that "if we add them all together a significant impact may result".
New Energy says its system relies on "peristaltic action," which refers to contractions which drive pressurized fluid to generate power.
The company says it is developing several systems which can be adapted for light vehicles or heavy trucks, in low-speed or high-speed situations.