| Burned or used in fuel cells, hydrogen is an appealing | | | | 500 km trip and also be light enough to haul around a |
| option for powering future automobiles. This nontoxic | | | | car. For a system weighing 600 kilograms (a |
| gas could serve as a pollution-free energy carrier for | | | | reasonable~ size of a vehicle), six kgs. would be |
| machines of many kinds. When it burns, it releases no | | | | stored hydrogen. Liquified stored hydrogen can |
| carbon . dioxide, a potent greenhouse gas. | | | | improve it's stored energy density and could be used in |
| And if hydrogen is fed into a fuel cell stack a battery | | | | cars, it drawbacks notwithstanding. Neverthe less, One |
| like device that generates electricity from hydrogen | | | | world-renowned carmaker BMW is pushing this |
| and oxygen it can propel an electric car or truck with | | | | technology onto the road. The vehicle called |
| only heat and water as by products. Fuel-cell powered | | | | HYDROGEN-7 will incorporate an, internal combustion |
| vehicles could offer more than twice the efficiency of | | | | engine capable of running on either gasoline for 500 |
| today's automobiles. Hydrogen could, therefore, help | | | | Kms. or on liquid hydrogen for 250 kms. |
| ease environmental problems, including air pollution and | | | | Chemical compaction: to raise energy density scientists |
| its hazards. | | | | have been able to take advantage of the chemistry of |
| Weight for weight, hydrogen contains three times the | | | | hydrogen itself. In it~ liquid phase, hydrogen molecules |
| energy of gasoline (petrol) but it is impossible to store | | | | contain two bound atoms each. But when hydrogen |
| hydrogen gas as compactly as the conventional liquid | | | | molecules are chemically bound to certain other |
| fuel. One of the most challenging technical issues is | | | | elements, they can be packed even closer together |
| how to efficiently and safely store enough hydrogen | | | | than in liquid hydrogen. |
| onboard to provide the driving range and performance | | | | Some researchers are focusing on a class of |
| the motorists demand. Feasible storage devices hold | | | | substances called reversible metal hydrides, which |
| sufficient hydrogen to support today's minimum | | | | were discovered by accident in 1969 at the Philips |
| acceptable travel (driving range--almost 500 kms)--on | | | | Laboratories in the Netherlands. Investigators found |
| a fuel tank that does not compromise on luggage | | | | that a Samarium-Cobalt alloy when exposed to |
| room. These tanks have to be filled or recharged in a | | | | pressurized hydrogen gas it would absorb hydrogen, |
| few minutes. Lot many researchers in the U8 Internal | | | | somewhat like a sponge soaks up water. When the |
| Energy Agency are expending considerable effort to | | | | pressure was then removed, the hydrogen within the |
| overcome these limitations. Infact, 17 governments are | | | | alloy reemerged in other words, the process was |
| committed to advancing hydrogen and fuel-cell | | | | reversible. |
| technologies. In 2005 the US Department of Energy | | | | In the US, scientists like Jame Reilly and Gary |
| provide4 $ 30 million to fund the 80 research projects. | | | | Sandrock, pioneered the development of hydride |
| A 500 km. minimum driving range is one of the principal | | | | alloys. This work formed the basis for today's widely |
| operational aims of the auto industry. Engineers believe | | | | used Nickel-Metal hydride batteries. The density of |
| that a~allon of gasoline is equal, on an energy basis, to | | | | hydrogen in these alloys is 150 % more than liquid |
| a kilogram of hydrogen. (One US gallon is almost 3. 8 | | | | hydrogen! Such properties of metal hydrides are well |
| litres) Whereas today's automobile needs about 20 | | | | suited to automobiles. Although the current metal |
| gallons of gasoline to travel 500 km., the typical fuel-cell | | | | hydrides have limitations, many automakers see them |
| vehicle would need only 8 kilograms of hydrogen. | | | | as the most viable low-pressure approaching the near |
| Several automakers have tested about 60 hydrogen | | | | future. Toyota and Honda automotive engineers, are |
| -fuelled prototypes and demonstrated driving ranges of | | | | planning a so-called hybrid approach in a system that |
| 200 to 300 kms. | | | | combines a solid metal hydride with moderate |
| By 2010 some auto companies expect the first | | | | pressure (lower than 10, 000 psi), which they predict |
| production of fuelcell cars to hit-the road. A hydrogen | | | | could achieve a driving range of more than 500 kms. |
| storage system must carry enough fuel for at least a | | | | |