Fuel for tomorrow

29/11/2000

Fuel for tomorrow the world faces two big challenges in the new millennium. One, to meet energy demand and two, combat rapidly worsening air quality. The solution to both the challenges lies in producing cleaner energy. Our main source of energy is oil, a limited and polluting resource. Humankind has consumed more of it in the last 50 years than in its history. Our vehicles continue to burn non-renewable petroleum fuels.

The cause for worry is not just the depletion of reserves of petroleum fuels. The air pollution caused by combustion in vehicular engines is as vexing a problem. Diesel exhaust has traces of over 40 substances that are listed by the California Air Resource Board as toxic contaminant and probable human carcinogens. In petroleum-fuelled vehicles, alkenes and benzene, together with polyaromatic compounds, add to the carcinogenic nature of vehicular emissions. Vehicular exhaust accounts for more than 65-70 per cent of air pollution in the metropolitan cities of India.

Aware of the gargantuan problem at hand, concerted efforts are being made world over to develop the technology for an alternative, renewable and clean fuel and hydrogen is fast emerging as one such alternative.
Gas for the future Hydrogen can become an excellent alternative fuel. It can be produced from water. Therefore, it is universally available. On combustion, it reacts with oxygen to form water again. A characteristic that allows us to call it a renewable and non-polluting fuel. About 160 years ago, William Grove, a British scientist, discovered how to generate electricity from hydrogen using a hydrogen fuel cell a kind of battery in which gaseous hydrogen and atmospheric oxygen reacts to form water, producing an electric current in the process. A thin, semi-permeable membrane keeps the two gases hydrogen and oxygen apart in the cell and allows the chemical reaction to proceed in a controlled manner. Grove did demonstrate the possibility of producing energy from the hydrogen cell but the technology remained impractical. The power generated was economically inefficient. Nobody, in that age of steam engines, imagined that vehicles one day would be powered by the same method.

Powering the Future tells the amazing story of how a tiny Canadian company, owned by Geoffrey Ballard and his colleagues, revolutionised the simple hydrogen cell mechanism. They brought back to humankind Grove's neglected invention, in a better, more usable form. The book, in the first few chapters, chronicles the events and describes how, from a humble beginning, in a makeshift laboratory, in a motel in the us, the company fought against stiff odds and intense competition.
After Grove William Grove in 1846 had constructed a bank of 50 cells, calling it the gaseous voltaic battery. Grove's invention languished in obscurity until 1889, when two scientists attempted to turn it into a practical device. They replaced the oxygen in the cell with air and the pure hydrogen with an impure industrial gas obtained from coal. A virtually solid electrolyte and platinum as catalyst were used to produce 1.5 watt of power from the cell. Commercial potential, though, remained a dream till the 1990s.

Throughout the first half of the twentieth century, attempts were made to build fuel cells that could convert coal or carbon directly to electricity. Though the experiments were not too successful then, they led to the creation of molten carbonate cells, one of the five leading fuel cell technologies in use for stationary power generation.

Meanwhile a hydrogen- oxygen cell, with an alkaline electrolyte, using the inexpensive nickel as catalyst had also been developed.The cell required preheating to at least 150

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