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19 April 2010

Hydrogen still in the eco-car race

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Hydrogen, one of Earth's most abundant elements, once was seen as green energy's answer to the petroleum-driven car: easy to produce, available everywhere and nonpolluting when burned

Hydrogen energy was defeated by a mountain of obstacles - the fear of explosion by the highly flammable gas, the difficulty of carrying the fuel in large, heavy tanks in the vehicle, and the lack of a refueling network. Automakers turned to biofuels, electricity or the gas-electric hybrid.

But hydrogen, it turns out, never was completely out of the race. Now Israeli scientists and entrepreneurs claim to have brought hydrogen energy a step closer by putting it in much smaller, lighter containers.

Rather than using metal or composite cylinders of compressed gas that look like bulky scuba gear, hydrogen is packed into glass filaments which, once out of the lab, will be only slightly thicker than a human hair.

These 370 glass capillaries are bundled into a glass tube called a capillary array, about the width of a drinking straw. The scientists say 11,000 such arrays will fuel a car for 400 kilometers (240 miles), take less than half the space and weight of tanks currently installed in the few hydrogen cars now available.

"We have shown new materials that can store more hydrogen than any other system," says Dan Eliezer, chief scientist of C.En Ltd., the company based in Geneva, Switzerland, where the Israelis are developing their invention.

The scientists make no attempt to improve the standard fuel cell, which is not much different today from when it was invented more than 150 years ago. A fuel cell makes electricity from chemical reactions involving hydrogen and oxygen, producing only water vapor as a byproduct. The fuel cell can be compared with a standard car's engine, while the capillary arrays would be comparable to the gasoline tank.

(Associated Press)

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