Electric power may become universal at last

1 February 2007

The first seriously legless land-transport came with the ‘iron horse’, also known as the steam locomotive, which was heat-engined and coal-fired. Railways’ first no-muscle-drive dry-land competitors were road vehicles, some of which were renderedauto-mobile by heat engines and some by battery-powered electric motors, but the electric cars were soon ousted by their noisy, smelly rivals, and have only in more recent times enjoyed hope of a comeback. However, for mass transit, the heat-engined locomotive has long given way to your and my favourite motivation – the electric kind.

Railways have had a tough time against roadways during the century or so in which liquid hydrocarbon fuel plenty has made mass transit escapable for relatively affluent motorists conveying few or no passengers. That luxury may dwindle, at least for a while, until our notorious contemporary fuel problems are sorted out, but the importance of mass transit is growing again as traffic conditions worsen, general pollution increases and natural resources decline.

Electric power has immense potential here. It already dominates the railways’ supply of traction but before long it may liberate trains from traction through wheels. Visionary engineers have experimented with magnetically levitated stock – not rolling stock – driven without traction wheels along track that acts as a linear electric motor.† And at long last there appear to be prospects for the construction and commercial operation of what are affectionately known as ‘maglev’ railways.

The propulsion of aircraft has, regrettably, never been a job for electric motors, but magnetically levitated trains are being ‘flown’, just clear of their track on the ground, driven along by the track’s electromagnetic field: and, in time, such trains could be competing with fast airliners. Though held aloft by magnetic rather than aerodynamic lift, the trains are of course still, like aircraft, subject to aerodynamic drag, but, like aircraft, they can still reach very high speeds.

The idea of maglev trains dates back to the 1930s but it has been realised only slowly, and mostly in Germany, where it originated. Even there, scepticism has hindered its uptake, and some technical glitches en route have not helped. The latest mishap, last September, killed about a score or more of passengers on a German test track. The last I have heard, however, suggests that at least Japanese and Chinese proponents have not given up their projects.

Unashamedly partisan, I should like to see electrically powered transport triumph in the air, even if only at altitudes measured in centimetres. Especially now that high-flying aviation is so much under a cloud because of its climate-threatening emissions. One modern answer to greenhouse gas emitters is of course the hydrogen fuel cell, and there have been intimations that such cells could provide the power to propel aircraft as well as to drive their auxiliary and ancillary equipment. Hydrogen fuel cells have, notably and historically, supplied power for spacecraft.

Even if fuel cells proved feasible for aircraft propulsion, hydrogen might still sneak heat engines back into aviation in defiance of electric power technology. For, at least in theory, hydrogen could fuel future aircraft engines of the internal combustion variety without exhaling a whiff of greenhouse gas. The hydrogen could be produced by electrolysis of water, using climatologically relatively inoffensive hydroelectric or nuclear power. Thus certain types of electrical generation could at least partly remove the heat engine’s dominance of transport.

The long-postponed return of the electric automobile is also expected now, and by some in high places. At the USA’s Los Angeles motor show the chairman and chief executive of no less a corporation than General Motors, Rick Wagoner, has reportedly said: ‘We see a logical journey from standalone, largely mechanical automobiles to vehicles that run on electricity’. And GM is still, I believe, the world’s biggest manufacturer in the business.

Hitherto, as far as I am aware, no very great protests have been made about the pollution of outer space by combustion products, so it might be thought that established rocketeering methods would preserve the supremacy of combustion artefacts for extra-terrestrial propulsion. But our people are not shy of the cosmos either. Such things as ion thrusters will no doubt keep electrical space-travel power systems at the height of modernity, when the time comes to evacuate our plundered and overheated planet.

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