Fuel for thought

As oil stocks run out and environmental pressures intensify, the car industry is turning to fuel cell technology.

Never in history has the relationship between humans and technology had such profound and far-reaching consequences as the addiction of people to cars.

Motorised transport in the UK has increased ten-fold since the 1950s. In the US, since 1969 the vehicle population has grown six times as fast as the human population. Americans own 34 per cent of the world’s cars. Between 1900 and 1984 they scrapped more than 640 million vehicles.

Since the 1950s, some of the disadvantages of motor vehicles have become increasingly apparent. They consume half the world’s oil and create a quarter of greenhouse gas emissions. Cities are congested and polluted, with car use linked to smog, and life-threatening illnesses such as asthma and bronchitis. Moreover, the big car companies are rushing into partnerships to build cars in China, where there were fewer than two million cars in 1996, a figure that could increase 50-fold by 2015.

‘If ever a human invention has reached a critical moment in its history, it is the internal combustion car,’ says Jim Motavalli in a new book published this week. Motavalli, who is editor of E:The Environmental Magazine in the US, has written about the motor industry for 15 years.

Not just wishful thinking

The car, he argues, has hardly changed in its lifespan: ‘For 100 years we’ve defined it as 1,600kg of steel rolling on rubber tyres.’ And for most of that time it has been powered by an internal combustion engine. But, he predicts, it is now becoming clear that the combustion engine is on its way out. ‘The notion that internal combustion is in its last days is not solely environmental wishful thinking, but also the opinion of a growing number of top-level motor executives,’ he says.

It also seems to be the opinion of the government-backed Automotive Innovation and Growth Team, which, The Engineer revealed last week, is to call on the government to develop and underwrite a plan to set up a hydrogen refuelling infrastructure.

Motavalli claims to have detected among the big car makers a seriousness about clean cars where before he found only ‘a wilful denial of serious environmental concerns’. This took the form of attacking the evidence for global warming and deflecting blame with claims that today’s cars are 90-96 per cent less polluting than those of 35 years ago, and that ‘a 1996 model car can be driven about 60 miles and still give off fewer smog-forming emissions than a 1965 model parked in the driveway all day with its engine off’.

Motavalli senses changes in attitude, which he puts down to a genuine realisation that the end of cheap oil may be at hand. Demand could soon exceed supply, and world production could peak as soon as 2007, according to some estimates.

What will replace the internal combustion engine? The answer seems to be some form of electric car. This could be a relatively familiar battery-powered electric vehicle. A transitional phase could be some form of hybrid, combining combustion and electric power to overcome battery cars’ problem of limited range. But the ideal solution seems to be the fuel cell EV.

For those who find it hard to imagine the car without a combustion engine Motavalli points out that in the early days of the car the dominance of internal combustion was by no means a foregone conclusion. Faced with driving round on top of a tank of highly inflammable petrol, many people preferred steam or electric power.

But, being self-contained, the petrol engine slowly won favour. Improvements made to it from 1905 onwards — most decisively, the invention of the self-starter – saw off the competition. steam more or less died out by 1910 and electric power a decade later.

One result of this is that pure, battery-driven electric cars are not much more advanced than they were 90 years ago. if powered by lead-acid batteries, their range is limited. Nickel-metal hydride cells are better, but expensive, while other types, such as lithium-ion cells, have disadvantages related to the hazardous nature of their chemicals.

EVs are thought of as ‘zero emission’ but it is often forgotten that the electricity they produce may well come from a fossil fuel power station. Even then, however, they produce a 13th of volatile organic compound emissions of the average petrol car, a sixth of its nitrogen oxide emissions, and less than 1,000th of its carbon monoxide. They can potentially make a significant difference to local pollution levels in cities.

The vision that is capturing the imagination of environmentalists and car firms alike, though, is the fuel cell. Again, this is not new technology. The principle of using hydrogen as a fuel and generating electricity in a reverse of the process of electrolysis was first demonstrated in 1839. The only by-product is water. Fuel cells were used in the US space programme because they could generate electricity at the same time as producing drinking water. ‘If hydrogen is produced from renewable resources, like photovoltaics and wind power, cars would become virtually emission-free,’ says Motavalli.

But there’s the rub. Though the technical problems surrounding fuel cells have mostly been solved, fuel remains a stumbling block. At present, hydrogen is produced only in small quantities: if it is to power vehicles production facilities need to be set up. There is no infrastructure for distributing hydrogen. It has to be stored and transported under pressure, requiring a new network of filling stations with pressurised tanks – perhaps with photovoltaic cell arrays to produce their own hydrogen. But this means billions of pounds of investment.

Then there are safety concerns, though Motavalli makes a strong case that these are accepted because they are familiar.

So it is likely that the first fuel cells will use some form of liquid fuel – probably methanol. The advantage here is that because it is a liquid it could be distributed by the existing petrol station network. But to be used in a fuel cell it first has to be broken down, in a process called reformation, to produce hydrogen. A reformer is a complex piece of equipment which adds weight to the car, and getting it to respond quickly enough acceleration is needed has caused problems for engineers. And, of course, such a car would still be powered by fossil fuel, and would still emit roughly similar amounts of CO2 to a direct injection diesel.

Nonetheless, companies such as DaimlerChrysler, GM and Ford insist they are on track to have production-ready cars by 2004 (see sidebar). Hybrids such as the Toyota Prius and Honda Insight are already here.

Of course, says Motavalli, all this could be missing the point if we only replace gridlocked fossil fuel burning cars with gridlocked clean cars. He admits that curing society’s car addiction may prove difficult. Meanwhile, cleaning up the car would be a start. He quotes energy campaigner Dan Becker: ‘We need to change America’s love affair with the car. It’s hard to influence the thinking of 240 million Americans, but only 12 companies make the bulk of the world’s cars. It’s much easier to turn them around.’

Sidebar: On the road to revolution

All the big car makers are carrying out serious R&D on fuel cell cars. The latest development is GM’s Autonomy concept, unveiled at January’s Detroit motor show.

This is designed around a fuel cell powertrain, with drive-by-wire technology for steering, braking and other systems. The cell and all the working parts are contained within a 150mm-thick skateboard-shaped chassis, to which a range of customised bodies could be added. Customers of the future could even lease multiple bodies and swap them for different uses. A universal ‘docking port’ at the centre of the chassis connects all the body systems and controls to the chassis.

Wagoner describes Autonomy as ‘potentially the start of a revolution’ in car design and use. GM vice president of R&D Larry Burns says it would allow an almost endless variety of vehicles to be built on just two or three common chassis designs, emitting only water from the tailpipe and using renewable energy.

GM has also demonstrated fuel cell versions of existing models, such as a Zafira people carrier and a Chevrolet pick-up, and it expects to have fuel cell vehicles in production for fleet use in two to three years. These could be refuelled from a central hydrogen station.

Consumers may have to wait until the end of the decade for a hydrogen fuelling infrastructure, but GM also believes it is within two years of perfecting a reformer that would allow fuel cell cars to run on sulphur-free petrol as a ‘bridging fuel’. Remaining problems with the reformer include size, weight and the high precious metal content (for catalysis) and hence cost, but GM demonstrated a Chevy S-10 gasoline fuel cell pick-up truck last August.

In Europe DaimlerChrysler led the way with the Necar I (new electric car) in 1994. It formed an alliance with fuel cell specialist Ballard of Canada, and was later joined by Ford and Volvo. Necar I was a large Mercedes-Benz van, the interior of which was entirely taken up by the fuel cell, with hydrogen tanks on the roof.

By Necar III the equipment fitted into an A-Class, though it took up the whole of the vehicle behind the front seats. Necar III used methanol, but the reformer suffered from acceleration problems. In the latest evolution, Necar IV, the fuel cell equipment was fitted within the A-Class’s sandwich floor. It ran on liquid hydrogen, though using this presents problems because of the extremely low temperatures at which it has to be stored.

Last year DaimlerChrysler delivered a hydrogen fuel cell van, a modified Sprinter, to a courier company in Hamburg, on a two-year trial, and plans to launch a car derived from Necar IV in 2004.