David Shapshak
Hydrogen, the world’s most plentiful substance, may be the energy source of future motor cars. With natural fuel resources diminishing, the need for alternative energy sources has been growing, and scientists have been looking for as efficient an option as petroleum.
While part of the concern is environmental (fuel combustion engines damage the atmosphere), some is forward thinking: there are only so many natural fuel resources. An alternative must be found.
Most attempts have focused on solar power or electric engines. These types of cars have made it through a variety of prototype stages, but are unlikely to be taken up by the world at large for a variety of reasons, including cost, lack of speed and performance and the lack of power points to recharge the car’s batteries.
But hydrogen propulsion answers some of these problems. Hydrogen constitutes more than 90% of matter, occurring in nature in compound form. The lightest of all atoms, it makes up the hydrocarbons such as raw petroleum and water, as well as methane, the main component of natural gas.
It does not have a negative effect on the atmosphere and it can be effectively extracted in huge quantities from hydroelectric plants.
But hydrogen has problems of its own. It must be stored in gas bottles under high pressure or in liquid form, which means cooling it to the extreme temperature of – 253C.
Liquid storage introduces another problem: how to transfer the super-cool liquid. The extreme cold would mean an attendant would have to wear an insulation suit to fill a car’s tank. This, however, can be overcome by using an automated pump system that plugs directly on to the car’s “petrol” cap. A collaborative partnership was founded to construct an experimental filling station, which has been completed and is in use near Munich’s airport.
Buses at Munich airport are experimenting with the high-pressure storage option, with gas bottles on their roofs pressurised to 250 bar – 25 times that of normal atmosphere.
German car manufacturer BMW is test-driving a range of its seven-series cars with liquid hydrogen tanks (hydrogen requires a large-capacity engine to produce the power output that matches a normal mid-range engine, and a larger tank). The luxury-car maker has been working on hydrogen technology for 20 years, and says it is ready for commercial use.
The German government is taking the issue of hydrogen as an alternative energy source seriously and even held a “hydrogen symposium” last year.
However, because of the infrastructure needed to provide it as easily as petrol, hydrogen is still much more expensive than today’s hydrocarbon fuels.
But, says Professor Ulrich Wagner of the Munich Technical University, its potential makes it a worthwhile avenue to pursue, as hydrogen cars will represent 10% of the automobile market over the next 20 years. It will also solve some of the carbon monoxide problems the world is facing from conventional combustion.
Toyota has engineered another alternative energy source car, which uses fuel cells to propel it. However, it differs from most other battery-powered vehicles in that it runs dually on batteries and on a petrol engine. The fuel engine kicks in when extra power or speed is needed, and while its emissions are significantly less than conventional cars, the difference is noticeably less obvious to the driver. The BMW cars will also be “bivalent”, or able to run on conventional fuel.