Is the clean car coming?

February 2003

Despite recent setbacks, the battle to break the monopoly of the internal combustion engine is still on. Battery driven cars are out of favour but fuel cell cars and hybrids - combining normal engines with batteries - will be widely used in ten years. It's not often that you find environmentalists protesting about a company's refusal to manufacture a car. But the placards outside the Ford offices in San Francisco last October denounced the company's decision to ditch the Th!nk City model. Following its unveiling in Europe in 2000, it was introduced to the US in a flurry of Los Angeles glitz in January 2002-only to be discontinued months later.

The Th!nk City runs for only 53 miles at a stretch, with a top speed of around 56 mph. But the car is all-electric: it needs no petrol and produces no pollution. It was once billed as the car of the future; now it is a has-been that never really was.

This is the latest in a series of recent blows to the electric-vehicle (EV) industry. General Motors has stopped producing its flagship model, the EV1. Meanwhile, GM and DaimlerChysler (who, along with Ford, constitute the "big three" US car manufacturers) teamed up with other automobile companies to take out a lawsuit against the state of California's "zero-emission vehicle" policy, which stipulates that from 2003, 2 per cent of all vehicles sold in the state should emit no polluting exhaust gases, and 8 per cent should be close to zero emission.

Despite the Californian ruling, there are few full-feature models available to US consumers. One is the Toyota RAV4-EV-of which under 400 had been sold to date. The manufacturers say that there just isn't the demand. Around 1.5m new vehicles are bought every year in California alone, but there are only 5,000 or so electric cars on the state's roads. EV enthusiasts, however, claim that companies aren't really interested in selling them. The number of "clean cars" of all types on the roads is no more than, roughly, 45,000 in the US and 20,000 in Europe.

Why does the challenge to produce a clean car exist at all? The one thing that everyone agrees on is that oil will not last forever. Whilst arguments continue over exactly when global oil production will peak, or how much oil might be hidden beneath the Alaskan tundra, or whether George W Bush covets Iraqi oil even more than Saddam's head, no one doubts that this is the century in which fossil fuels will begin to dry up. When even BP adopts "Beyond Petroleum" as its slogan (though the company subsequently disowned it) you have to suspect that something is up.

There are two separate problems with oil: sources and pollution. US oil reserves may be dry within the decade, which will mean greater reliance on oil from the middle east-the world's most unstable region But even while there is still oil to burn, the consequences of doing so are unwholesome. When petrol is consumed in an internal combustion engine, the main products are heat and carbon dioxide, the principal greenhouse gas responsible for global warming. Car exhausts contribute about 14 per cent of all global fossil fuel emissions of carbon dioxide; in the US the proportion is closer to 20 per cent.

That is not the only problem. Exhaust fumes contain a noxious cocktail: soot particles, which can cause respiratory problems; toxic and carcinogenic hydrocarbons such as benzene; and the deadly, poisonous gas carbon monoxide. Petrol burning also produces nitrogen oxides, which react in the atmosphere to form pollutants that cause breathing problems, eye irritation and the brown pall of smog. Air pollution smothers the world's big cities, choking the citizens to death. Every year, over 3m deaths are caused at least in part by air pollution, according to the World Health Organisation. California's legislative attempts to reduce car pollution may be heavy-handed and over-optimistic, but they are understandable in one of the US states with the worst air quality. (The objections of the car makers to legislation are also understandable, however. "North America is unusual in having the only regulations calling for zero emissions, but simultaneously having the lowest energy prices in the world, which provide limited incentive for customers to choose more fuel efficient vehicles," says Bernard Robertson, a senior vice president at DaimlerChrysler.)

But battery-driven electric vehicles such as the Th!nk City aren't the only solution. Ford claims that its decision to drop the Th!nk range-and indeed the entire Th!nk R&D division, intended "to exclusively develop, market and deliver a wide range of environmentally sensitive mobility solutions"-was made so as to focus on other low or zero-emission vehicles powered by devices called fuel cells or by a hybrid of the internal combustion engine and electric batteries. These two options-fuel-cell vehicles (which are also, in the end, electrically powered) and hybrid electric vehicles-now seem the most likely "green" cars to achieve wide commercial development. Another possibility is the use of cleaner fuels from renewable sources, such as methane from biological waste (biogas) and ethanol, which can be made from corn.

The automobile industry is, in fact, entering a period of uncertainty and experimentation akin to that experienced in the audio and television industries over the past decade or so, and to that currently facing the microelectronics industry. That is to say, survival depends on making fundamental changes, and quickly, to the basic technology; but no one is agreed on the best solution, and some of those being explored will inevitably fall by the wayside. An optimistic view is that the apparent demise of battery EVs represents nothing more than this inevitable wastage and does not spell doom to all green vehicle technologies.

Pessimists, however, point to a series of mountainous hurdles. Consumers will be reluctant to make a large investment in an untested new technology, no matter how good the environmental arguments-especially if they risk seeing their multi-thousand-pound cars become as obsolete in a few years as a Betamax video recorder. And car culture seems to be heading in the opposite direction, especially in the US, where a demand for gas-guzzling "sport utility vehicles" (big, fast and flashy) has driven the average fuel efficiency of cars and trucks to a 21-year low of 20 miles per gallon. The Bush administration has shown itself steadfastly opposed to serious efforts at improving this figure.

And who can criticise consumer reluctance about clean vehicles when there is no infrastructure to support them? Fuel-cell cars need completely different types of fuel from those you will find at the local filling station-but where do you get it from? The oil companies wait for these new vehicles to find a mass market before they put in the relevant pumps, while the car companies wait for the fuel supplies before they risk mass producing the vehicles. How to break the impasse?



GREEN MACHINES

In an industry where marketing depends mainly on sex and speed, electric vehicles-redolent of milk floats and golf carts-were always going to be hard to sell. The car companies have not always helped matters. The low speed models such as Ford's Th!nk Neighbor or DaimlerChysler's GEM are indeed basically souped-up golf buggies. They are designed for short, local trips and have a range of about 25 miles before needing to be recharged. They are classified as "low speed/neighbourhood electric vehicles," with top speeds of typically 25mph. The principle is sound enough-one needs little more than this for the school or supermarket run-but the reality is about as appealing as a Sinclair C5, and could never aspire to be more than a second vehicle for most people.

The late Th!nk City was altogether a different beast. It could accelerate from 0 to 30 mph in 7.2 seconds, and the US version was produced with air conditioning and power steering. It looked sleek and neat and could be recharged by plugging into a normal mains socket. Admittedly this could take four to six hours, but doing it overnight at off-peak rates makes a full charge-up potentially cheap. GM's EV1, modelled on similar lines, cost its users no more in electricity than they spent on petrol (and that is at US fuel rates).

The range of these EVs is, however, limited by their batteries. Some use nothing more than the old-fashioned lead-acid batteries that power the electrics on most cars today. The EV1 can run for up to 120 miles at a stretch when driven by a nickel/metal-hydride battery, first introduced in the 1980s. These batteries hold more electrical energy per kilogram of weight than a lead-acid battery.

Weight is an important factor in EV battery technology: if the battery is very heavy it partly defeats its own propulsive object. This is one reason why rechargeable lithium batteries, like those used in laptop computers and mobile phones, are attractive for electric vehicles: not only do they hold a lot of energy but they are light. Early attempts to use lithium batteries were beset with hazards-they used lithium metal, a highly reactive substance, and one of Mitsubishi's prototype Chariot EVs burst into flames in 1996. But the new lithium batteries are safe, and are used in Ford's prototype e-Ka, which has a range of 120 miles at a cruising speed of 50 mph.

With the simplicity of the plug-in recharging cycle, battery-powered EVs seemed well placed to corner the zero-emission market-until a combination of cost (these batteries are pricey) and overall consumer apathy persuaded the car companies otherwise. Purists could point out that these vehicles weren't really "zero emission" anyway because the electricity from the grid was, in all probability, produced from fossil fuel burning in the first place-the burden of greenhouse gases and pollutants was simply being shifted. But that was never really the issue. Sources of electricity are potentially renewable: for example, hydroelectricity, photovoltaic cells, or wind or wave power. And the pressing problem of noxious emissions in urban centres is avoided by EVs.

In any event, car manufacturers have not ditched the battery-powered car altogether. They are pinning their hopes on the hybrid electric vehicle (HEV), which uses a combination of a petrol-powered internal combustion engine and an electrical battery. The savings in fuel consumption and reductions in emissions that these hybrids offer can be big, and they look promising as a way of easing the transition to cleaner vehicles.

The idea is so simple that it could have been realised decades ago, if battery technology had been up to it. The reason you never need to plug your standard lead-acid battery into the mains is that it gets charged up by the car's motion, in the same way that a rotating wind turbine produces electricity. But this "reclaimed" power is used only for the purposes of powering the headlights, radio, windows and so forth. Why not the wheels too?

HEVs are fitted with electronic sensors and microprocessors that let the vehicle "decide" when it would be advantageous to supplement or substitute the engine's power with that stored in the batteries. Fuel consumption increases, for example, when the vehicle accelerates, or climbs hills, or is started up. It is on these occasions that an HEV's battery kicks in to provide the extra juice. When idling at junctions, jams and traffic lights, the engine may be turned off completely. (In Seattle, to take a typical example, over 80 gallons of petrol are burned up per person each year in cars that are motionless or barely moving.) "Regenerative braking" mechanisms capture some of the energy otherwise wasted in braking (where it dissipates as heat) and use it to charge up the battery. HEVs can achieve twice the fuel economy of conventional vehicles, and have much lower emissions.

The Honda Insight and the Toyota Prius, the two most widely used HEVs on today's roads, are rated as 90 per cent cleaner than an average new conventional car, and can travel between 500 and 700 miles on one tank of petrol. Ford is developing a car called the P2000 Prodigy, described as "a viable candidate for Ford's first mass produced HEV." DaimlerChrysler's premier HEV concept, the ESX3, is still in development. A drawback of these vehicles is that the batteries (lead-acid or nickel/metal hydride) eventually wear out and cost several thousand dollars to replace. But the battery warranties typically extend to 80,000-100,000 miles, by which time you may have saved that much in fuel costs.

The critical question for many motorists is: how does it feel behind the wheel? According to one test driver of the Toyota Prius, "it is no different from any other car, except it's quieter, quicker, and gets better mileage" (in this case up to 66 mpg). And you can watch what the onboard computer is up to in a little animated display panel which shows how the vehicle switches between the internal combustion engine, electric motor and electric generator. It would be hard to find a reason why all new cars are not HEVs, if it wasn't for the cost. But the differential is no longer great, and is falling all the time. DaimlerChrysler's projected ESX model in 1996 would have cost $60,000 more than a standard model. For the ESX2 in 1998 the difference would have been $15,000, and for the ESX3 two years later it would have been just $7,500.



HYDROGEN AND FUEL CELLS

But HEVs are a stop-gap, a palliative to wean us off petrol. Eventually we are going to need other fuels. One such is already widely used in the US: it is called E85, and is a mixture of 85 per cent ethanol (the alcohol in spirits) and 15 per cent petrol. Ethanol burns more cleanly than petrol: it produces carbon dioxide, but less hydrocarbon and carbon monoxide. And the fact that ethanol can be made from the abundant grain of the US midwest makes it an attractive option. Ford, GM and Daimler-Chrysler all make vehicles that run on E85-they need no more than a slightly modified engine-as do Isuzu and Mazda.

There is no fuel, however, that generates more controversy and confusion than hydrogen. Guardian readers witnessed a baffling debate on the "hydrogen economy" in late 2002, provoked by Jeremy Rifkin's claim that it "has the potential to end the world's reliance on imported oil." Is hydrogen an energy source, debated the correspondents, or an energy carrier? Doesn't it cost more energy to make it than we get back by burning it? Isn't the best use of hydrogen as a fuel for nuclear fusion?

Hydrogen power has long been plagued by myths and half-truths. As the most abundant element in the universe and one of the two elements in water (hydrogen, after all, means "water-former"), it seems to promise the irresistible notion of "energy for free." Ever since Jules Verne said in 1874 that "water will be the coal of the future," the "water-powered car" has been a persistent (and chimeric) fantasy.

So let's be clear. Hydrogen can be a fuel: you burn it, like petrol, except that the only chemical product is water, not carbon oxides or hydrocarbons or soot. So it is the perfect green fuel. But first you have to extract it from other compounds, because pure hydrogen is extremely rare on our planet. You can do this in many ways, but they all cost energy-so do we gain anything in the long run? The answer can be yes, for the reasons given earlier: the energy can come from renewable sources, and you don't create localised urban pollution when you burn hydrogen in a car.

It is possible to use hydrogen directly as a fuel: to burn it in an internal combustion engine much like the ones used for burning petrol. BMW's 750 hL car does this, storing hydrogen in liquid form in pressurised, cryostatically cooled tanks. But it is unlikely to catch on, because there is a much better way of getting the energy out of hydrogen. Internal combustion engines are inefficient, squandering between two-thirds and four-fifths of the energy in the fuel. But if hydrogen is burnt in a fuel cell, the efficiency can, in theory, be close to 100 per cent.

When petrol or hydrogen is ignited in air, the chemical reaction between the fuel and air creates heat. A fuel cell conducts the same combustion reaction but in a much more controlled way that channels the energy directly into electricity.

In effect, the combustion of hydrogen involves the transfer of electrons from hydrogen atoms to oxygen atoms. These atoms then join together to form water. A fuel cell consists of two electrodes connected by an electrolyte, a substance that conducts electricity. The electrons flow from the hydrogen atoms at one electrode to the oxygen atoms at the other. The end result is that hydrogen and oxygen are converted into water and electricity.

It is the opposite of the process called electrolysis, in which electricity is used to split water into its components, hydrogen and oxygen. Electrolysis of water was first observed in 1800 by English scientists using the first electric battery, invented that year by Italian Alessandro Volta. Thirty-nine years later, a Welsh barrister, William Grove, realised that the reverse process could be used to generate electricity. He devised the first fuel cell.

But fuel cells were not used as power sources until the 1960s, because they were more expensive than batteries. The first applications were in spacecraft, such as in the Apollo missions. Here cost did not matter: it was the light weight of the cells that counted. Since then, the cost has been reduced far enough to make fuel cells viable for everyday power applications. The leading commercial fuel cell for consumer devices, especially zero-emission vehicles, is called a polymer electrolyte membrane (PEM) cell.

PEM fuel cells have been pioneered by Ballard Power Systems in Vancouver. Ballard cells have been used in the city's buses since 1993, and Daimler Benz (as it was then known) used them in its prototype Necar vans, unveiled in 1994. In 2003, DaimlerChrysler will launch a pilot project in which 30 fuel-cell city buses based on the Mercedes-Benz Citaro model will be operated in ten European cities: Amsterdam, Barcelona, Hamburg, London, Luxembourg, Madrid, Oporto, Reykjavik, Stockholm and Stuttgart. This will test their performance in environments ranging from Arctic chill to the sweltering Spanish summer.

Some fuel-cell vehicles, such as the original Necar prototype, run on methanol, which acts as a "hydrogen carrier." Methanol is a compound containing a high proportion of hydrogen atoms bound to carbon and oxygen. The methanol is first passed over a catalyst that releases the hydrogen, and this is then fed into the fuel cell. Methanol is a better fuel than pure hydrogen in some important respects. In particular, it is a liquid: you can pump it into your tank like petrol. Hydrogen is a gas that can be liquefied only under high pressure and at very low temperatures-which makes it potentially hazardous to store and to transport. But methanol fuel cells are not exactly zero-emission devices: the carbon in the fuel is converted to carbon dioxide.

For zero-emission fuel-cell vehicles, the problem of hydrogen storage remains one of the main hurdles. Many research teams are now looking for materials that can soak up hydrogen and then release it again. Metal hydrides are one possibility, but they are heavy. DaimlerChrysler is experimenting with a hydrogen-rich compound called sodium borohydride. Researchers at the US National Renewable Energy Laboratory (NREL) in Colorado have reported that a form of pure carbon, called carbon nanotubes and consisting of long, hollow carbon tubes several thousand times thinner than a human hair, can store large amounts of hydrogen, as if they were molecule-sized storage cylinders. They claim to have exceeded the storage density goal set by the US department of energy. But other teams have been unable to duplicate their results, so this idea remains in limbo.

The biggest problem may be producing hydrogen in the first place. In principle, it can be manufactured in endless quantities by electrolysing water. But this uses up as much energy in making it as you get by burning it (more, in fact, since there is some waste). That is no objection, though, if the electricity comes from renewable sources like solar cells. The NREL is one of several laboratories studying the "photocatalytic" splitting of water into its elements. They are looking for a material that can absorb sunlight and use the energy to split water, at the same time acting as a catalyst that loosens the chemical bonds holding water molecules together so that they break more easily. Several candidate materials have been discovered, but no one has yet succeeded in making the process efficient enough to provide a commercial source of hydrogen. Success here would be big news, as Stephen Poliakoff acknowledged in his 1996 play "Blinded by the Sun", in which an ambitious scientist falsifies his data to claim photocatalytic hydrogen production in his "Sun Battery."

Other potentially renewable sources of hydrogen include hydrogen-producing micro-organisms such as certain kinds of algae, which use sunlight to split water in a variant of photosynthesis. But most commercial hydrogen comes at present either from electrolysis (which makes it three times as costly as petroleum), or from a chemical process called steam reforming, in which natural gas and steam are reacted over a catalyst at great heat to form hydrogen and carbon oxides. Again, this is an energy-hungry process.



A BUMPY RIDE

If hydrogen could be made cheaply, the transition to hydrogen-powered fuel-cell vehicles would still be a bumpy ride. Would oil companies be prepared to add a hydrogen pump to all of their filling stations? It is not an impossibly utopian scenario, and a Californian project is showing how painless the changeover might be. SunLine Transit Agency in Thousand Palms, which provides public bus transport for the Coachella Valley, converted its fleet to green vehicles in 1994, switching overnight from diesel buses to vehicles powered by natural gas. With the support of public and private sector partners, SunLine is now switching to hydrogen power. It runs two Hythane buses, which burn a blended fuel of 80 per cent natural gas and 20 per cent hydrogen, as well as two zero-emission buses: the XCELLSiS/Ballard ZEbus and a hydrogen fuel-cell bus called ThunderPower, which began operating commercially in the Coachella Valley in November. SunLine also runs the first two-passenger street-licensed fuel-cell vehicle in the US, called the SunBug.

These vehicles are supplied by a hydrogen refuelling station in Thousand Palms, operating since the spring of 2000, where hydrogen is generated on site using solar and grid-powered electrolysis. California is slowly accumulating hydrogen stations: Honda opened a hydrogen production and refuelling station in 2001 at their headquarters in Torrance; BMW has installed a liquid-hydrogen station at their Oxnard facility; the California Fuel Cell Partnership operates a small refuelling station in west Sacramento and a new site opened in Richmond in November.

"Today's model of tomorrow's world" is how SunLine likes to bill itself. The US department of energy, at least, seems to take that prospect seriously, aiming for a "meaningful introduction" of fuel cells for power generation of all sorts by 2005. It wants one tenth of the US total energy consumption to come from hydrogen by 2030. In Iceland-a country with ample hydroelectric and geothermal energy resources, but no fossil fuels-the plans are even more ambitious. Methanol-powered buses are to begin operating in Reykjavik this year and, in the next few years, the city intends to replace all its buses with fuel-cell vehicles. The scheme is backed by Shell, which is building the methanol filling stations, and DaimlerChrysler. The Icelandic government wants to remove all dependence on imported fossil fuels within a generation, and Bragi Arnason, a chemist at the University of Iceland, believes that by 2040 the country will be the first to have a complete, self-supporting hydrogen economy.

Not even the most ardent optimist can anticipate that happening in Europe, the US or Japan. But neither is it possible any longer to characterise the car manufacturers as dinosaurs resisting any movement towards cleaner vehicles. Indeed, as the American commentator Jonathan Rauch has put it: "Breaking the 100-year monopoly of the internal combustion engine is as vast a project as capitalism has ever undertaken. Given the immensity of the risks involved and the billions of dollars of investment required, the project is nothing short of planetary in scale."

No one who thinks seriously about the future of motoring can doubt that a radical shift must get underway within the next decade. That will require changes of habit among consumers and car makers. Good intentions will not suffice, but neither will draconian legislation: persuasive incentives to maker and buyer will have to be found by governments. Green cars cannot be allowed to become the automotive equivalent of organic vegetables: fine for the few who can afford it.