BUSINESS

Fuel cells

A new kind of gas station
 

Oil and car firms are finally agreed on how to make fuel-cell cars a reality
 

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AS A United Nations conference on climate change opened in Milan this week, the Bush administration restated its opposition to the Kyoto Protocol. Paula Dobriansky, America's undersecretary of state for global affairs, criticised the treaty as “an unrealistic and ever-tightening regulatory straitjacket”. The right way to tackle warming greenhouse-gas emissions was to embrace new technology that transforms how energy is produced and promotes, not impedes, economic growth.

One such technology is the fuel cell, whether used to power cars, heat houses or replace conventional batteries in mobile phones and laptops. A fuel cell is a sort of battery that produces electricity if it is fed hydrogen. The hydrogen combines with oxygen in the air to produce electricity and hot water. Unlike old-fashioned electric cars, the battery in a fuel-cell electric car should never go flat, provided it does not run out of hydrogen fuel.

There are two big obstacles to fuel cells becoming the green saviours that the Bush administration, among others, hopes for. The cost of manufacturing a fuel-cell electric engine needs to fall by 90% to compete with petrol engines, and each country using fuel cells would need a completely new distribution network to deliver the fuel needed for the cells. Mass production is likely to lower engine costs, perhaps sooner than many expect. But the infrastructure problem has always seemed even more formidable.

Sceptics have long insisted that building such a delivery system would prove too costly: $100 billion in America alone. But the oil giants and the carmakers, once hostile to a new technology that threatens their investment in conventional vehicles and fuel-delivery networks, could prove the doubters wrong. Pushed by environmental regulators in California—where the new governor, Arnold Schwarzenegger, wants to build a “Hydrogen Highway”—they are now getting together to plan an affordable alternative strategy: tapping into the existing nationwide natural-gas grid to produce hydrogen gas for fuel cells at existing petrol stations (known by Americans, confusingly, as “gas stations”). This compromise could be a crucial milestone on the road to a hydrogen economy.

As evidence of the increasing probability of change, Bill Ford, boss of Ford Motor and great-grandson of the company's founder, stated recently that “fuel cells will finally end the 100-year reign of the internal combustion engine”. Indeed, hydrogen-powered buses have already taken to the streets of Vancouver, Stuttgart, Chicago and Sacramento. London will soon have some fuel-cell buses. Fedex and UPS are trying out fuel-cell delivery-trucks.

These fleet vehicles work out of central depots, where storage of hydrogen is simple. The vehicles have a predictable range. So refuelling on the road is not critical. Getting fuel cells into private cars was bound to prove far trickier, and take longer, due to the need for refuelling points to be as ubiquitous as today's petrol stations.

Yet most of the big global car firms are within a couple of years of selling fuel-cell vehicles: General Motors, Ford, Toyota, Honda and DaimlerChrysler are leading the way. The main reason? From 2008, they must ensure that 10% of their new cars meet California's “zero emissions” law. If they do not, they could risk heavy penalties or possibly be shut out of the world's fifth-biggest economy.

Until now, the likeliest solution to the car-refuelling problem was to make hydrogen from petrol. The big oil companies wanted this, as it would minimise the impact on their business. The idea was that tiny chemical plants on board vehicles would convert gasoline to hydrogen for the fuel cell. Lobbied hard by Exxon Mobil, the world's biggest oil and gas company—and the most curmudgeonly on matters green—America's Department of Energy spent millions on researching how to produce hydrogen efficiently from gasoline. Another variation used methanol: DaimlerChrysler spent ten years and $1 billion on this before giving up. Nearly all of the big car firms have now ditched these clunky solutions, since extracting hydrogen from petrol or methanol adds considerable weight and complexity to cars, yet still produces some tail-pipe emissions.

Oil firms and carmakers are now hoping to feed the fuel cell directly with hydrogen. Filling stations would be hooked up to the natural-gas grids that criss-cross all rich countries, and reformer plants (being developed by United Technologies and others) would then extract the hydrogen from this hydrocarbon gas at the petrol station, allowing drivers to “fill her up”. Honda, Japan's second-largest car firm, and Plug Power, an American fuel-cell firm, have even developed an “energy station” that makes hydrogen for a fuel-cell car from natural gas at home—providing heating and water for domestic use as well.

GM now sees the potential in turning gas into hydrogen. In a new report, it argues that a roll-out of 12,000 hydrogen pumps in urban areas and along main highways could give 70% of America's population reliable access to the fuel at a cost of only $10 billion-$15 billion. Larry Burns, GM's head of research, compares that to the $160 billion (in today's money) spent by federal government on building highways nearly five decades ago and concludes: “Fuel infrastructure will not be the show-stopper for fuel cells. This is quite doable.”

Now all the carmakers need to “do” is drive down the costs of fuel cells from their current level—GM claims $500 per kW but most experts say higher—to the $50 per kW of petrol or diesel engines. That will take some years. Even so, thanks to the power of mass production to diminish costs and the desire of politicians seeking to appease activists, the first green cars could soon be appearing in your rear-view mirror.

Fuel cells were invented before the internal combustion engine, but have only recently become commercially viable. They work by combining hydrogen and oxygen to produce electricity, while avoiding both combustion and emissions any nastier than water and heat. Cost, bulk and unreliability were barriers to their widespread use, but research by companies such as Ballard Power Systems has helped to overcome these.

Fuel cells hold the promise of revolutionising two industries: power-generation and motor cars. Spurred by tightening emissions laws in California and elsewhere, car makers are developing a new generation of hydrogen-powered vehicles. They have the support of big business, but making and storing hydrogen fuel effectively and safely remains problematic (using carbon is one solution). The absence of a hydrogen-fuel infrastructure is another hurdle, though Iceland and America are making progress in this area.

Governments in America and Europe are encouraging the adoption of hydrogen power, though for different reasons. In the not-to-distant future miniature fuel cells could supplant conventional batteries in most electronic devices.

How a fuel cell works
 

IT GETS wet and hot and that’s all. This, in short, is the attraction of a fuel cell. In simple terms, it gobbles up hydrogen and combines it with oxygen from the air to generate electricity, avoiding combustion and by-products any nastier than water and heat.

Although there are rival varieties of fuel cell, the most promising is the proton-exchange membrane. This is a sandwich of two electrodes, a cathode and an anode, with an electrolyte stuffing called a polymer membrane placed in between.

At the anode, hydrogen gives up its electron with the help of a platinum catalyst. While the hydrogen passes across the membrane in the form of positively charged ions, its electrons, which cannot cross the membrane, instead stream around an external circuit, rather as electrons do if you connect the poles of a battery. And as with a battery, this current can power a car or a computer. When the hydrogen ions reach the cathode, they are reunited with electrons and combine with oxygen to create water and heat.

If the fuel that is used is pure hydrogen, then the process will live up to its clean image. But if the hydrogen is made on board by a “reformer” that consumes hydrocarbon fuels, such as methanol, natural gas or petrol, the whole process will be slightly polluting—though far less so than engines today.

Fuel cells

Intel on wheels
 

Can a small Canadian company overthrow the internal-combustion engine?

VISITORS to Ballard, a chemical-to-cars firm based in Burnaby, outside Vancouver, are welcome to walk around the laboratories and workshops where small-scale manufacturing of fuel cells is under way. They are free to talk to the chemists who have found cheaper ways to make the components of a fuel cell. Here is the polymer membrane that used to cost $750 a square foot; and here also the graphite frame that cost $100 a few years ago. Ballard can now make both for only $5 each. But along one side of the laboratory is a windowless, cream-painted plywood wall; and what happens behind it is strictly off-limits.

That is where a team of 30 engineers is working out how to mass-produce fuel cells, so that they can replace the internal-combustion engine in cars and buses. A few years ago fuel-cell engines were more than 100 times dearer than petrol engines; today the ratio is ten to one, and falling. “We’re only at the beginning of reducing costs,” says Firoz Rasul, the firm’s chief executive. “We aim to be competitive with whatever is already used.”

Fuel cells promise to retain all the benefits of individual mobility, while removing the nasty stuff that comes out of exhausts—including much of the carbon dioxide, which is implicated in global warming. Ballard has a fleet of prototype, fuel-cell-powered buses lurching around the streets of Chicago. At the Detroit Motor Show in January, Ford plans to reveal a fuel-cell car based on Ballard technology that it hopes will make as great an impact on the 21st century as the Model T did on the 20th. William Clay Ford, who was appointed chairman-designate of the firm last month, has long been keen to demonstrate the firm’s green credentials.

Fuel cells work by taking hydrogen and oxygen and putting them through a chemical reaction to produce electricity and water. Mounted on a car, they provide a supply of electricity to power an electric motor, with water coming out of the exhaust pipe. Since hydrogen is volatile and awkward, the vehicle carries methanol or even gasoline in its tank; a small chemical “reformer” strips the hydrogen from the hydrocarbon fuel. The system is so efficient that very little carbon dioxide is produced.

For most of its life, Ballard has concentrated on science. Versions of fuel-cell technology were developed chiefly for use in space and in warfare, where getting the job done mattered more than the cost. Ballard was little more than a contract-research laboratory working for, among others, the Canadian defence ministry. But about ten years ago its engineers realised that a technology called “proton-exchange membrane”, invented by America’s General Electric in the late 1950s, might have civilian uses. That meant bringing the costs of fuel-cells down to earth from outer space.

Thanks to its research, Ballard has a strong hold over the fuel cell’s intellectual property, owning around 300 patents at the last count. But if it is to become the Intel of the industry, making the components at the heart of the fuel-cell engine, it still has an awful lot of work to do.

The chief task, entrusted this summer to the 30 engineers at work behind the cream-painted wall at Burnaby, is to turn Ballard from a research laboratory into a mass-production company. The firm has set itself the target of cutting costs by the 90% needed to make fuel cells competitive in vehicles by 2003. One of the original managers, Mossadiq Umedaly, vice-president and finance director, left in June because there was no role for him in the new structure. In the summer the firm appointed a new chief operating officer, Layle Smith, who is a seasoned troubleshooter from Dow Chemical. His expertise has been in turning round troubled manufacturing units. Another senior executive in charge of power-generation fuel cells has a background in American utilities.

At the moment, Ballard is concentrating on five products in three markets. As well as two fuel-cell systems for vehicles (one for cars, another for buses and lorries), there are separate systems for large and small generators—fridge-sized units running on natural gas to provide electricity for a building that is not attached to the grid. The most futuristic product is a tiny fuel cell to produce power for use in portable applications, from hedge trimmers to mobile telephones.

But Ballard has set itself a much harder task than that faced by the early semiconductor firms. At least they were supplying a completely new sort of device. Ballard, by contrast, is trying to displace existing technologies, in which huge industries have invested decades of research and training. America’s clean-air legislation is a help, but Ballard has also wisely sought to recruit industrial partners which have a stake in the old technology. Mr Rasul realised that not only would this provide the know-how needed to put a fuel cell into an engine or a power unit; it would also help Ballard to get fuel cells into more than just its own prototypes.

Ballard has an impressive pack of industrial partners. Daimler-Benz (as it was until its merger with Chrysler) was the first. It has a 25% stake in Ballard. Since 1993 it has built an alliance with the Canadian firm to work on fuel-cell systems suitable for use not just in laboratories-on-wheels, but in real vehicles, such as versions of the latest Mercedes A-class small car.

Other car makers were at first unimpressed by fuel cells. But last December, Ford bought 15% of Ballard; now these two, plus Daimler, are tightly bound in several joint ventures. One joint venture, known as DBB Fuel Cell Engines, is led by Daimler and based in Stuttgart. It takes fuel cells from Vancouver and fits the auxiliary pumps, valves and control systems needed to make them work in a car. The other main joint venture, Ford-led Ecostar, takes the machinery from Stuttgart and fits it into electric motors, transmission and control equipment to make a fuel-cell engine that can turn the wheels of a car or a bus. A similar series of joint ventures has been put together to develop fuel cells to generate electric power.

Ballard is now the supplier of choice for six out of ten of the world’s top car companies. But not everything is going its way. It faces competition from Allied Signal and International Fuel Cells (part of United Technologies Group) in America, De Nora in Italy and Siemens in Germany. Among the car makers, General Motors and Toyota are also developing fuel cells. All these competitors are experts in mass production. Similarly, in the power market, Ballard faces competition from electrical companies, such as Mitsubishi in Japan and Westinghouse, Plug Power and ERC in America.

There is also a lingering question whether fuel cells will ever amount to more than niche products—for vehicles in regulated markets or as a power source for customers who need high-quality uninterruptible electricity, such as chip factories. It is a bad sign, for instance, that the firm’s share price (see chart) is as responsive to endorsements from politicians eager to curb emissions as it is to industrial news. Yet Ballard has reason to be optimistic. Firms such as Royal Dutch/Shell and BP are keen to become green “energy” companies, not just oil companies. They are promoting the use of gasoline or even natural gas as the source of the fuel cell’s hydrogen. Once the oil industry joins Detroit, Ballard’s bus will have all the top people on board.

At last, the fuel cell
 

A device that has been neglected for a century and a half is about to take its rightful place in industrial civilisation

LOVELY technology, shame about the cost. That is the usual comment on fuel cells—a method of generating power that is 40 years older than the petrol engine. Fuel cells helped to put a man on the moon by providing astronauts with electricity and water but they have, so far, proved far too expensive for most down-to-earth applications.

That, however, is changing fast. Over the past few years engineers have been designing fuel cells that will be useful outside space agencies. Their main motive has been the growing demand for pollution-free energy sources. But, as they approach their goal, they seem to have created something that may revolutionise two industries—power generation and motor cars.

Fuel cells produce electricity by reacting hydrogen and oxygen together electrochemically, rather than by combustion. The “exhaust” from this process is water—there are no noxious pollutants such as carbon monoxide and oxides of nitrogen. Nor, at least from the fuel cell itself, is there any carbon dioxide (CO2) that might contribute to the greenhouse effect. That makes fuel cells a double friend to the environment: if put in vehicles, they would not pollute the city streets; if put in power stations (or vehicles, for that matter) they could not add to any global warming that might be going on.

Though the practical reality is a little more sordid—realistic commercial designs for fuel cells often derive their hydrogen from chemical reactions that generate CO2, and some of the chemicals involved are, themselves, greenhouse gases—widespread use of fuel cells could still bring about significant reductions in greenhouse-gas emission (see chart) and would certainly improve the air quality in cities. It is these arguments, and the threat—or, in some cases, fact—of legislation to back them up, that have stimulated research into cells which might actually be candidates for use in vehicles and commercial-electricity generation. And, perhaps to the surprise of even the researchers themselves, this research has proved fruitful.

As a result, a commercial fuel-cell bus will be launched next year using an engine developed by Daimler-Benz. A car—cheap enough to compete with petrol vehicles—should, it is claimed, follow in 2003. Two years after that, Daimler expects to be turning out 100,000 fuel-cell engines, both for its own new A-class Mercedes and to supply other car manufacturers.

Fuel-cell power generation, meanwhile, has already arrived. A collaboration between Toshiba, a Japanese electrical company, and International Fuel Cells (IFC), which is part of United Technologies, an American conglomerate, is jointly mass-producing a unit known as the PC25. This is designed for people who need a reliable and (unlike a petrol-driven generator) clean power source, and are prepared to pay a little over the odds for it.

If this technology is indeed becoming commercial rather than experimental, it will have had a veritably mammoth gestation. The principle of the fuel cell was developed in 1839 by William Grove—a man who, although he ended his career as a judge, began as a physicist.

Fuel cells work by “reverse electrolysis”. As every schoolboy knows, water can be split into its constituent elements—hydrogen and oxygen—by the application of an electric current, and Grove, who was professor of experimental philosophy at the now-defunct London Institution, and a friend of Michael Faraday, was an early student of electrolysis. During his researches he discovered that when he disconnected his electrolytic apparatus, the process seemed to work backwards. This observation formed the basis of his invention.

So a fuel-cell consists of a fuel supply (hydrogen), an oxidant (oxygen, usually from the air) and two electrodes (the anode and the cathode) on either side of an electrolyte. This latter is a material that conducts electricity by the passage not of electrons, but of electrically charged atoms, or ions.

During the electricity-producing reaction, hydrogen atoms give up electrons at the anode and become hydrogen ions in the electrolyte. Electrons released at the anode travel through an external circuit to the cathode. On the way they can be used to power any form of electrical apparatus, such as a motor, just as a current from a battery might (see diagram above). At the cathode, the electrons and the hydrogen ions combine with oxygen molecules to form water (and also release some heat in the process).

The principle, therefore, is quite simple, but the chemical reaction is difficult to produce. There are five types of fuel cells, with varying degrees of promise and problems, but only two are anywhere near being practical propositions.

All five cells use catalysts to speed up the reaction, and several also rely on high temperatures. The most expensive sort of fuel cell is the alkali cell used in space vehicles. It enjoys the highest ratio of power to weight, but it needs expensive metals, such as platinum and gold, to coat its electrodes. Worse, its electrolyte is made of potassium hydroxide, which tends to react with CO2 in the air to form potassium carbonate. That means it needs a supply of pure oxygen, which adds even more to its expense.

Two other types of cell—molten-carbonate and solid-oxide cells—run at 600°C and 1,000°C respectively. This means they do not need expensive hydrogen as fuel. Instead, they can use methane, which is available cheaply in natural gas (and can also be made in an environmentally friendly way from plant material, known in the trade as “biomass”). At such high temperatures, and with the assistance of some steam and oxygen, methane (which is a hydrocarbon molecule compounded of four hydrogen atoms and one carbon atom) is easily reformed into hydrogen and CO2.

These cells do not need costly platinum coatings on their electrodes to act as a catalyst, either. But both types have their problems. The solid-oxide fuel cell requires fancy ceramics for its electrodes and an exotic mixed oxide (yttria and zirconia) as an electrolyte, while the electrolyte in a molten-carbonate cell is so hostile that its electrodes tend to give up the ghost regardless of their composition.

Only the remaining two cells, therefore, look like serious candidates for commercialisation. One, the phosphoric-acid cell, is the darling of those who hope to replace behemoth gigawatt-producing power stations with handy local ones. The other, the proton-exchange-membrane, or PEM, cell, should be able to assist in that and should also, its champions believe, become the main way of powering vehicles.

Phosphoric-acid cells run at 200°C. This makes them more manageable than the other two “hot” cells, but still allows them to use methane. The PC25 actually operates as a “co-generation” unit—that is, it exploits both the electricity from the cell and the incidental heat produced when the hydrogen and oxygen react. On this basis, it costs around $3,000 per kilowatt of capacity to manufacture—about double that of conventional generators.

At that price, the IFC/Toshiba consortium already has orders for at least 185 PC25s from organisations that need high-quality uninterruptible power supplies for sensitive medical or computing equipment. The Japanese and American governments have, however, been offering subsidies to the two companies to try to get the price down still further, so that the technology becomes cheap enough for general use. Success looks possible—the current price per kilowatt is half what it was two years ago and mass production would surely cut it further.

That, combined with the deregulation of the electricity market that is happening in many countries, would, so the visionaries hope, lead to the emergence of hundreds of power-service companies, supplying local, tailor-made electricity rather than bulk utility-style power delivered over cumbersome transmission lines.

This may seem like wishful thinking, but there are already signs of a trend towards such “distributed generation” involving small gas-turbine power stations. If fuel cells are cheap enough, they would make formidable competitors for these—and in Japan, Toshiba has teamed up with Fuji and Mitsubishi to install 100 fuel-cell generators ranging from 50kW to 11MW in order to see if the idea is viable. Though the Japanese government has been subsidising these field trials, the companies’ plan is to have commercial products by 2001, and to install 2,000MW-worth of capacity by 2010.

Electrical-power generation is, of course, fundamental to a modern industrial economy. But the application that is really starting to exercise people’s imaginations is transport. Indeed, the most optimistic commentators (not all of them in the pay of the fuel-cell industry) are talking of electric motors powered by PEM fuel cells taking over the role now played by internal-combustion engines.

Two car companies seem to be taking this possibility particularly seriously. Coincidentally, one of them is Daimler-Benz—the outfit that put the four-stroke internal-combustion engine into horseless carriages in the first place. The other leader is Toyota.

PEM cells go back to the late 1950s. They were developed by General Electric in America, and they have a solid electrolyte (the eponymous PEM). This operates at a reasonably low temperature—around 80°C—but until recently it required daunting quantities of expensive platinum as a catalyst to make the reaction happen. In fact, a stack of cells powerful enough to drive a car would have set you back $30,000 for the platinum alone.

That was the problem faced by Ballard Power Systems, a high-tech Canadian company, when it started working on PEM fuel cells in the mid-1980s. Only when it teamed up with a British speciality chemicals and metals company, Johnson Matthey, in 1993, did the firms find a way to cut back the platinum. They worked out how to adapt Matthey’s catalyst technology (developed, in a beautiful irony, for cleaning up cars’ petrol engines through catalytic exhaust converters) for use in PEMs.

Johnson Matthey’s technology was a method of dispersing the platinum in a catalyst in a way that maximises its surface area (the catalytic brick in the exhaust of an average car contains a surface area of platinum equal to three soccer pitches). As a result the cost of the platinum in a PEM big enough to power a small car has plummetted to a more manageable $140.

But Ballard has not only been smart in the way it has deployed its technology. It has also made clever use of industrial partners. In 1996, it formed a joint venture with General Public Utilities in America to work on a PEM fuel cell for use in power generation. And on the transport side, it tied up with Daimler-Benz. As these joint ventures develop, the industrial partners have a direct, financial interest in seeing products emerge from the collaboration.

Daimler-Benz, for instance, is investing $350m in Ballard. It is buying a 25% stake in the business, and is pooling its fuel-cell technology and related assets with the company. The two firms also have a joint-venture company—two-thirds of it owned by Daimler—to market the engines. Another industrial partner is Johnson Matthey, which has taken a small stake in Ballard.

The point of these partnerships is not just to bring much-needed capital into Ballard (since it went public it has anyway become a darling on America’s Nasdaq stockmarket). As Firoz Rasul, the company’s boss, points out, fuel cells need more than just the basic stacks and electrodes to earn their keep. They need whole systems, for control and so on, that are adapted to the particular application they have been designed for. Thus it takes a power company to see how best to adapt them into electricity generation. And it takes a car company of the stature of Daimler to work out how to tailor them to best effect in cars or buses.

So how close has all this dramatic progress brought the fuel-cell vehicle? And how well do present prototypes stand up to comparison with conventional petrol-engined vehicles? Both Daimler and Toyota have unveiled small cars with prototype fuel-cell engines. Toyota’s is a version of its small sport-utility vehicle, the RAV4, and it has a range of 500 kilometres (a little over 300 miles). The fuel-cell version of the A-class has a range of 400 kilometres. This is about the same range as a tankful of petrol will give you and almost three times as far as a battery-powered electric car can go without re-charging.

Both of these vehicles actually have their tanks filled with methanol, rather than hydrogen. The hydrogen is produced on board by a small chemical reactor using a process similar to the one that makes hydrogen from methane. This is an important point in the economics of running these cars, since methanol is a liquid, and therefore easier to handle than gaseous hydrogen or methane.

Even so, the two vehicles—still pre-mass-production prototypes—have a long way to go to match a petrol car’s economics. Today’s fuel cells cost about $5,000 per kilowatt to make, whereas a petrol engine costs about $50 per kilowatt. Industry experts reckon that the fuel cell will have a commercial future starting from the moment it gets the cost per kilowatt down under $200. Tweaking and mass production are the keys to bridging the gap.

Daimler and Ballard think they can shrink the size, weight and cost far enough to make the fuel-cell-powered A-class profitable with a production volume of 250,000 cars a year. Both they and Toyota believe that one big selling point will be the efficiency of fuel cells, leading to much lower fuel consumption than that of petrol engines (see chart). A PEM cell converts 30% of the energy in its fuel into useful work, compared with barely 20% for an internal combustion engine, so Toyota is confident that even its early models will be at least 50% more economical than petrol engines.

Both these prototypes are now on display at the Tokyo Motor Show. They are rather different vehicles: the Mercedes is a straightforward fuel-cell-powered electric car, but Toyota’s model is more complex. It has a smaller fuel cell (25kW compared with the Mercedes 50kW) together with a battery and a system for “regenerative” braking (when the brakes are put on, the electric motor acts as a dynamo generating power to be stored in the battery).

Toyota is generally wedded to the principle of such “hybrid” electric cars. In December, it will launch the world’s first commercial model, a Corolla that has a small petrol engine for use on the open road and an electric battery for city driving. So Toyota’s fuel-cell strategy is a development of this more conventional engineering.

All this activity seems to have caught the big American car companies on the hop. Only two years ago, Detroit dismissed fuel cells as blue sky research that would take decades to come to market. Now, they are born-again fuel-cell enthusiasts. Ford, General Motors and Chrysler are all working with Ballard or IFC to develop their own fuel cell prototypes. Indeed, Chrysler is concentrating on a petrol-fuelled version of the fuel cell—stripping hydrogen from the hydrocarbon ingredients of petrol with minimal emissions (of course). There would therefore be no need for anyone to spend heavily on an alternative fuel network. Delphi, a subsidiary of General Motors, is also interested in this route. It is working with two oil companies, Arco and Exxon, to develop better hydrogen-stripping reactors.

Several of Daimler’s European competitors are also crying “me too”. Renault, Volvo and Volkswagen all claim to be experimenting with fuel-cell cars. Only BMW seems to be standing aside. It is betting that, if hydrogen ever does take off as a fuel for cars, it will be burned in internal-combustion engines similar to today’s.

What do all these developments add up to? Daimler says it will review progress in two years’ time, but it already talks like a company that has seized the future. Its boast of 100,000 fuel-cell engines by 2005 indicates that it believes that this source of clean power, so elusive for decades, is at last taking to the road. The firm that brought the world the petrol-engined car 100 years ago is about to launch the product most likely to kill it.

Fuel cells and cars

The turning-point?
 

Another step towards a fuel-cell-powered car
 

AP

Also available with seats

MORE than 700 vehicles are on display at this year's Detroit motor show. One stands out. Among the serried ranks of cars and “sport-utility vehicles” is what looks like a giant skateboard. This is Autonomy, a prototype built by General Motors (GM) to explore the design changes that might come about if internal-combustion engines are replaced by fuel cells. The Bush administration's announcement in Detroit of a new programme, called “Freedom Car”, to develop fuel-cell-powered vehicles, encouraged fuel-cell enthusiasts.

In any good design, form follows function. Given a petrol or diesel motor, most engineers have opted for an engine compartment at the front of the vehicle, and a driveshaft that delivers power to the wheels. A passenger compartment sits behind the engine, and a luggage space is installed behind the passengers.

Arriving at an optimal version of this design took time. The first horseless carriages looked like the horse-drawn models from which they had evolved, and it was decades before they shook off the essential boxiness that resulted. General Motors' top managers do not want to repeat that process if fuel cells take over. So about a year ago they asked the company's engineers to start from scratch and design a fuel-cell-based platform that might form the basis of GM's advance into the new technology. The result is Autonomy.

At its simplest, a fuel cell combines hydrogen with oxygen to produce water and a flow of electric current. That electricity can be used to operate a motor, or, in the case of Autonomy, four motors—one attached to each wheel. In addition, unlike the power-generating elements of internal-combustion engines (the cylinders), which have to be arranged in a precise geometrical relationship with each other, fuel cells can be slung together any old how, so long as the wiring is correct. That means they do not necessarily have to be lumped together as an engine block, in the way that cylinders must.

Autonomy reflects the fact that a fuel-cell stack can be made flat and thin. The prototype is barely 15cm thick, although it is as long and wide as a conventional chassis. It contains not only the fuel cells and the storage system, but the motors, suspension and electronic control system. As GM envisages the concept, vehicle bodies would not only be manufactured separately from the chassis, but might even be sold separately. That would be possible because, rather than having mechanical links from controls to working parts, a motorist behind the wheel (or joystick, or whatever) of Autonomy would be driving “by wire”, rather like a jet-fighter pilot.

Autonomy has four attachment points for bodies, which might look like those of a conventional saloon, a coupé, a pick-up truck or even a sport-utility vehicle. Or they might take a new form never before seen—perhaps incorporating a new approach to safety. Indeed, it would be possible to have several different bodies, and to change them as need or desire saw fit.

There are several obstacles to overcome before a production version of Autonomy hits the road. One is price. A fuel-cell power-pack still costs about 100 times as much as a comparable internal-combustion engine. Prices are coming down, and performance and reliability improving, but the real motive for pushing fuel cells is their lack of noxious emissions. This allows them to pass environmental controls imposed by places such as California.

How to design a vehicle that can store hydrogen fuel on board safely, and in large enough quantities?

A potentially more serious challenge is how to store the hydrogen fuel on board a vehicle safely, and in large enough quantities. Hydrogen is a gas, which means that it has to be compacted somehow if a usable amount is to be carried. When mixed with air, it is also an effective explosive. Many solutions have been proposed: liquefaction, compression, absorption into solid compounds called metal hydrides, and on-board extraction from more conventional fuels such as petrol or natural gas are four that are peddled routinely.

One of General Motors' rivals, Chrysler, has now come up with a fifth possibility which is, in its way, as unconventional as Autonomy. The company's prototype Natrium minivan relies on a chemical called sodium borohydride. This is a fancy name for the hydrogenated version of borax laundry powder.

Natrium carries 175 litres of a 20% solution of sodium borohydride in water. Step on the throttle and the mixture is pumped past a catalyst made of ruthenium. This strips the hydrogen out of the compound, and feeds it to the vehicle's fuel-cell stack. The used slurry is then stored until it is time to refuel, when it is pumped out while a fresh batch is loaded.

Whether sodium borohydride could prove a feasible solution to the hydrogen-storage problem remains to be seen, but it is an ingenious idea. Both it and Autonomy demonstrate that the big car makers are taking fuel cells seriously. The American government has also stepped in by announcing a switch of support from studies of conventional fuel efficiency to studies of fuel cells, though cynics may note that this will tend to increase sales of petrol until the cells are introduced. But if they are, it will represent the most dramatic change in car technology since Carl Benz first chugged out of his garage in 1885.

Fuel cells meet big business
 

A device that has been a technological curiosity for a century and a half has suddenly become the centre of attention

“THE stone age did not end because the world ran out of stones, and the oil age will not end because we run out of oil.” Thus Don Huberts, who is convinced that fuel cells, which generate clean energy from hydrogen, will soon begin replacing power stations and cars that mostly burn coal, oil or natural gas.

Such dreamy talk would mean little coming from an environmentalist or an academic. Although such people have long been praising fuel cells, technical and commercial obstacles have largely kept the technology in the laboratory, barring the odd foray into space and the oceans. But Mr Huberts works for an oil company. And as head of Shell Hydrogen, a new division of Royal Dutch/Shell, his conviction reflects a dramatic shift in the thinking of big business.

The moment when an experimental technology becomes a commercial one is hard to define, but the new interest of oil companies, car makers, and power-engineering firms—almost all the industries that have a stake in the business, in fact—is a sign that fuel cells are crossing the line. Now that the energy business thinks that fuel cells are coming, they probably will.

To catch a glimpse of the fuel cell’s future, consider Iceland. Even though Iceland gets nearly all of its heat and electricity from clean hydro-electric and geothermal sources, its vehicles still use petrol and diesel. Look across Reykjavik’s spectacular waterfront at midnight in July, and you may see the smog dimming the bright, arctic sky. Bragi Arnason, a wizened academic known to his countrymen as “Professor Hydrogen”, has been trying to change that for two decades. Earlier this year he got his way, when the country pledged to become the world’s first hydrogen-powered economy.

This attracted Shell, DaimlerChrysler, a German-American car giant, and Norsk Hydro, a Norwegian energy firm experienced in making hydrogen. With local partners, they have set up a joint venture in the country. The project’s first phase, which kicks off later this year, will introduce Daimler’s fuel-cell buses, powered by hydrogen made using renewable energy. After that, predicts Mr Arnason, Iceland will start replacing all its cars and buses, as well as its fishing fleet, with fuel-cell-powered transport. Ultimately, Iceland sees itself exporting both hydrogen and its fuel-cell expertise.

But the companies have another objective too. Philip Mok, in charge of Daimler’s entry into Iceland, explains that the car maker wants to learn how to work with the oil companies. Car companies know that their plans to introduce fuel-cell vehicles will succeed only if a fuel is available. And that means persuading oil bosses that fuel cells are both a serious technology and a potentially profitable one.

There is some urgency. Car makers have been unveiling increasingly sophisticated prototypes in the past few years. In 2004 or 2005 Daimler and several rivals plan to launch commercial fuel-cell cars in America and Europe. Billy Ford Jr, head of Ford and the great-grandson of the car firm’s founder, even proclaims that fuel cells are “the only clean propulsion system”, and believes they will be the driving force behind his company in the next century.

Fuel-cell technology has been around for 150 years, so why is it attracting attention now? The reason is that a happy coincidence of greenery, market liberalisation and technology is finally making fuel cells cheap.

The first push came from politicians. Car makers began to take fuel cells seriously after California decreed that, by 2004, a tenth of all cars they sold in the state must not produce emissions, on pain of being barred from the market. The Californian edict was a boon to fuel-cell research. Car firms and fuel-cell specialists, such as Ballard, will have spent some $1.5 billion on R&D by next year.

Their results have been so promising that oil companies could not ignore the technology. One oil boss says they produced more technological breakthroughs in five years than battery research has in the past thirty. Such have been the advances that market incentives, not mere regulation, are now motivating firms.

Research into proton-exchange membrane (PEM) fuel cells, the most promising variety (see article), has reduced the amount of platinum needed, and made the electronics cheaper. Five years ago, for example, the amount of platinum required by a stack of PEM fuel cells for a car cost $30,000; now, it needs about $500-worth.

Thanks to such advances, the cost of a fuel cell has already fallen from the stratosphere to only a few thousand dollars per kilowatt of generating capacity. Car firms still have a lot to do: for fuel-cell systems to compete against the internal-combustion engine, their costs must come down to about $50-100 per kilowatt. Car makers are betting that mass production will help them close the gap after 2004.

By then, power-generation companies hope to be well established. Market research by Arthur D. Little, a consultancy, suggests that consumers will spend $1,000 per kilowatt for the benefits offered by small combined-heat-and-power units. Power generation is already “riding the coat-tails of the car companies’ cost reductions,” says Barry Glickman of GE Power Systems, part of the American conglomerate. He expects the cost of PEM fuel cells soon to be competitive with a range of alternative technologies, from coal to gas-fired generation.

Although the first generating products are already on the market, most are pricey and specialised. Within two years, consumers will be able to buy the first mass-market fuel cell. GE, working with America’s Plug Power, says it has developed a PEM fuel cell the size of a washing-machine, designed to provide electricity and, eventually, heat for a house or small office. The firm intends to start selling such generators in 2001 for $7,500 (dropping to half that price by 2005). Insiders believe this will become a billion-dollar industry within five years of its launch.

Firoz Rasul, Ballard’s chief executive, thinks that GE’s numbers are optimistic, but even he agrees that the eventual market for power generation will be enormous. John Loughhead of Alstom, a French firm that is Ballard’s partner in power generation, reckons that, if fuel cells really take off, they could account for as much as a tenth of the $50 billion a year global market for power-generation equipment ten years from now.

Two other forces are helping fuel cells in power generation. Energy deregulation in Europe and America allows new firms to set up cheap, efficient power sources (such as fuel cells) close to the consumer. Meanwhile, there is a proliferation of electronic devices in houses and offices, which would benefit from the high-quality power promised by fuel-cell generators.

Although people think the fuel cell is coming, not everyone agrees what fuel it will use. Despite Iceland’s enthusiasm, there is unlikely to be a market for hydrogen for some time. The lack of infrastructure and the difficulty of storage mean that other, dirtier ways of delivering hydrogen to fuel cells will almost certainly come first. The favourites are methanol or petrol in cars, and natural gas or propane for power generation. Each could be “reformed” to make hydrogen, without sacrificing all the fuel cell’s benefits.

One reason for the uncertainty is the tension between those, such as car firms and fuel-cell researchers, who see the direct use of hydrogen as the cleanest and most elegant use of the technology, and oil bosses, who worry that going direct to hydrogen is expensive and impractical, given current technology. Some fret that, if consumers get their hydrogen from their suppliers of natural gas, oil companies may even start to lose business.

But not all oilmen agree. BP’s Bernie Bulkin worries about gearing up to supply a less-than-ideal fuel such as methanol, only to find that a few years later everything has to be switched again to supply hydrogen. And some fuel-cell people, such as Ballard’s Mr Rasul, think that forging ahead with interim fuels would allow fuel cells to penetrate the market while the glitches in hydrogen storage and distribution are sorted out.

And there is yet another possibility. Exxon, one of the world’s biggest oil companies, has been cool toward fuel cells over the years. Its boss, Lee Raymond, is no environmentalist, and he maintains that the idea of man-made global warming is rubbish. Yet the firm decided recently to enter fuel-cell partnerships with General Motors and Toyota. The consortium is developing fuel-cell cars that will use cleaner petrol, to be distributed at its existing stations. Exxon hopes this will make consumers readier to accept the new technology. Although fuel cells using petrol would produce carbon dioxide, the main greenhouse gas, they would nevertheless be more efficient than the internal-combustion engine and produce none of the particles that cause pollution in cities.

This heterodoxy will probably rankle both idealistic Icelanders and the hydrogen experts at the car companies. However, they should take comfort. As Texaco’s Graham Batcheler explains: “We came around late to fuel cells, but we now recognise that the oil and gas business is going to change...whatever fuel emerges eventually as the choice for fuel cells, we want our consumers to fill up at a Texaco station.” In other words, even the traditional purveyors of fossil fuels, realists to a fault, now believe in fuel cells. For a technology that has depended on visionaries for 150 years, that is quite a breakthrough.

REPORT: ENERGY

The fuel cell’s bumpy ride
 

Motor manufacturers are betting heavily on fuel cells as the engines for tomorrow’s cleaner cars. But how to make and store the hydrogen fuel?

 

HFCLetter

Green but no slowcoach: a Cobra with hydrogen in the tank will attempt to break the 108mph land­speed record for fuel­cell cars this summer

THE thundering tom-toms just might be a sign of big changes ahead. Not long ago, dozens of people from around the world descended upon an idyllic country retreat in Canada for a most energetic pow-wow. The motley crew sat in a giant circle with native drums of every imaginable size and shape, and banged away till green inspiration struck. They then strategised about how to move the energy world beyond the filthy but durable workhorses of today—fossil fuels and internal combustion engines. They agreed that the future belongs to fuel cells, which produce clean energy by combining hydrogen with oxygen without combustion.

Now, here is the weird part: those peculiar percussionists were not wild-eyed greens, but sober technical experts from the world’s biggest car companies, energy firms and research laboratories. Indeed, the whole shindig was organised by the new hydrogen division of BP, an oil giant. The reason for their enthusiasm was that, more than 150 years after its invention, the fuel cell is finally about to become a commercial reality.

In simple terms, fuel cells combine hydrogen and oxygen to produce electricity, while avoiding combustion and emissions any nastier than water and heat. Although there are variations on the theme, the most promising type of fuel cell is the “proton-exchange membrane”. This is a sandwich of two electrodes—an anode and a cathode—with a polymer membrane serving as an electrolyte stuck in the middle (see illustration, or click for an animated version). At the anode, hydrogen gives up its electron with encouragement from the platinum catalyst. While the hydrogen ions (protons) slip through the membrane, the electrons are forced to travel around an external circuit, producing a current that can power a car or a computer. When the protons reach the cathode, they join with the electrons and combine with oxygen from the air to create water and heat. The result is clean energy with no harmful emissions.

Already, it is clear that the electricity industry will be turned on its head by fuel-cell “micropower” units that are about to come on the market. Given the inadequacies of today’s battery technology for such things as laptops and mobile phones, it seems likely that tiny fuel cells will transform the market for portable power, too.

But some think that fuel cells might even reach hydrogen’s promised land: to become the power source of choice for transport. Nearly all of the world’s leading motor manufacturers are trying to develop fuel-cell cars. Goaded on by government threats of “zero emission vehicle” mandates in California and curbs on carbon emissions in Europe, they are pouring billions of dollars into fuel-cell research. They vow to have fuel-cell cars on the market by 2004.

So the hydrogen revolution is about to transform ground transport? Do not hold your breath. In fact, fuel cells might yet prove to be a costly and humiliating flop in cars, even as they take off in other applications. The reason is that the world is just not set up to deliver hydrogen on demand.

In tackling that slightly awkward problem, fuel-cell fans fall into two camps. One camp thinks that hydrogen infrastructure will be far too costly to build for decades to come, and so wants to use some interim fuel during the transition. Such voices point to studies suggesting that building a hydrogen infrastructure could cost $100 billion or more in America alone. The other camp reckons that the investment needed will be much less, and insists that going direct to hydrogen is the only sensible option. Who is right, never mind who will win, is unclear.

Everybody agrees that the greenest and most elegant way to feed fuel cells is using hydrogen fuel directly. Indeed, some day in the future, the hydrogen may even be derived from renewables. Until that Utopia arrives, many firms plan to use interim fuels such as methanol or petrol and extract hydrogen on board the vehicle using a “reformer”. Such cars would not be emission-free, but would still be much cleaner than today’s vehicles.

The methanol champions argue that, unlike petrol, their fuel can be produced from a variety of sources ranging from natural gas to “biomass” (ie, plant matter, cow dung and such like). This may make methanol attractive in poor countries, which use a lot of biomass. Rich countries may prefer methanol because it would reduce their dependence on OPEC.

Advocates note that there are big plants today producing methanol; indeed, there is a global glut. They suggest that this is enough to feed early fuel-cell cars, and so help to achieve mass-market economies of scale—at which time hydrogen can make a graceful entry. Maybe. The danger is that as methanol fuel cells take off, output will have to be increased and retail distribution expanded, leading eventually to stranded assets. Sceptics argue that it might be cheaper to go straight to hydrogen.

Even so, DaimlerChrysler gushes about its “direct methanol” fuel cell, which needs no reformer at all. It recently demonstrated a 3 kilowatt version which powered a go-kart. If perfected, this would be a genuine breakthrough. However, huge technical hurdles remain and commercialisation looks a decade or two away.

“Car makers are pouring billions into fuel–cell research and vow to have fuel–cell cars on the market by 2004.”

The best argument for methanol reformation is that it clearly works, while petrol reformation remains in doubt. That is chiefly because petrol—a far more complex fuel than methanol—contains carbon-carbon molecular bonds that take a lot of energy to break. Petrol reformers must operate at high temperatures (ie, 800°-900°C), while methanol reformers run at perhaps a third of that temperature. The methanol backers gloat that they have more or less solved the chief technical puzzles: Daimler’s new NECAR5 boasts a reformer that powers a 50 kilowatt fuel-cell stack, while petrol reformation remains stuck in the laboratory.

But the petrol researchers insist they have made great progress in recent months. Bill Innes of Exxon Mobil claims that his firm’s fuel-cell alliance with General Motors and Toyota, which has been spending $100m a year on research, has made a breakthrough with its laboratory reformer. He is hoping to install it in a fuel-cell vehicle by the end of this year.

However, even if his team can get the size and cost to reasonable levels, it will be difficult to ensure that the fuel-cell has a snappy response. That is because the complicated workings of a petrol reformer tend to slow the response of the fuel cell to an intolerable level. Exxon Mobil claims that its equipment solves this problem by controlling the fuel composition precisely. But that is a task that today can barely be done on the laboratory bench. Whether and when this can be done on the open road is unclear.

If petrol reformation takes off, methanol will lose out. After all, petrol is ubiquitous and familiar and the world is set up to deal with it on a massive scale. However, there is a wild card that could still cause petrol reformation to fail in the market, argues Robert Williams of Princeton University. That is the recent arrival of highly efficient hybrid cars such as the Toyota Prius and Honda Insight that combine petrol engines with electric motors. He argues that as long as the main competition for the petrol fuel-cell car was the conventional internal combustion engine car, the economic case made some sense. The higher initial cost (an extra $5,000, including the reformer) could be more than offset by the likely doubling of the fuel efficiency plus the environmental benefits. However, these new hybrids achieve levels of fuel efficiency and emissions comparable to those of petrol fuel-cell cars today—but at a much lower cost, even when the manufacturers’ hidden subsidies are discounted. It is quite possible that petrol fuel-cell cars could lose out to hybrids and thus fail to capture the market share needed to succeed.

Encouraged by the clouds hanging over reformers, some argue for a move direct to hydrogen. Before contemplating the economics, however, enthusiasts for such an approach must first surmount three hurdles that opponents claim are insurmountable: safety, storage and supply. The easiest to tackle is safety. Hydrogen is often perceived as dangerous, but that reputation is largely undeserved. It is true that hydrogen is inflammable. But methanol is corrosive and extremely toxic, and petrol is both a carcinogen and easily ignited. A related factor is that hydrogen is a gas at room temperature and disperses rapidly, unlike methanol and petrol. With public education and garage-style handling, hydrogen can be at least as safe as today’s fuels.

A tougher challenge is storage. The problem is that hydrogen has the smallest atomic structure of all elements. That causes two problems when trying to handle it. One is that, being so tiny, hydrogen atoms can wiggle through the crystal lattice of the material used to contain it. The leakage from a pressurised hydrogen tank could be significant. The second problem is a consequence of the fact that, being so small, hydrogen is also exceptionally light. In a typical gaseous storage system, it has only a tenth of the volumetric energy density of petrol.

The obvious answer is to compress the hydrogen. Impco, the leader in this field, has devised an ingenious all-composite tank that can hold enough hydrogen at a pressure of 5,000 pounds per square inch (psi) to travel 300 miles. The tank meets stringent safety standards and is expected to cost only about $1,000. Holding more than 40 gallons of hydrogen, it is still far bulkier than the average petrol tank. But the firm is testing a tank capable of storing hydrogen at 10,000psi, which should be much more compact.

The best way to store hydrogen, however, may well be in some solid form. That would offer advantages of safety as well as convenience. Some experts point to the promise of so-called carbon nanotubes—a form of carbon that experiments suggest could reversibly store astounding quantities of hydrogen. But that is fantasy for the time being. A more tangible approach involves metal hydrides, which store and release hydrogen in the way that the batteries in some of today’s mobile phones and laptop computers do. The firm that pioneered the rechargeable nickel-metal hydride battery, Energy Conversion Devices (ECD) of Troy, Michigan, claims to have repeated the same trick with fuel cells.

Though rivals are sceptical, ECD’s Alastair Livesey says tests prove that its new metal hydride can be recharged in just a few minutes; will last for over 500,000 miles; and can travel 300 miles without refuelling. The tank will weigh about 220 pounds—twice the weight of a full petrol tank—but be only slightly larger, and drivers could fill it up with hydrogen at filling stations. The firm and its oil industry partner, Texaco, believe they can get this project from the research phase to the mass market within five years.

But what about supply? In itself, hydrogen is just a fuel, not an energy source. Hydrogen is the most abundant element in the universe, but rarely exists in its free state on earth—being found normally in combination with oxygen (as water) or carbon (as methane and other hydrocarbons). As a result, it always takes energy to free it for use, whichever way it is produced.

One approach is to strip hydrogen out of hydrocarbons. Firms already do this today by reforming natural gas at centralised plants. The hydrogen produced in this way is used to make ammonia fertilisers and to “lighten” heavy grades of crude oil. The earth’s vast reserves of coal could also be tapped. The production costs of hydrogen from such centralised approaches could be competitive with that of petrol, but the snag is that an expensive system of pipelines or tankers would still be needed to get that hydrogen to consumers.

Another approach is electrolysis, which zaps hydrogen free from water using electricity. This process is energy intensive, so large-scale electrolysis is likely to take off first in places with cheap, clean sources of hydro-electricity. However, it does benefit from the fact that its two prerequisites, electricity and water, are fairly well distributed around the world.

Even if safety, storage and supply are sorted out, does a direct shift to hydrogen make economic sense? It might, provided three big “ifs” are fulfilled—if the hydrogen is phased in over time, if governments give hydrogen strong regulatory support, and if manufacturers produce hydrogen cars that consumers actually want to buy.

To reduce the cost of manufacturing fuel cells and win public acceptance, central and local authorities will have to encourage a shift to hydrogen for fleet vehicles such as city buses, delivery trucks and so on. Since such vehicles are roomy, compressed hydrogen tanks will not be much of a penalty. Fleets of commercial vehicles have the added advantage of refuelling at central depots. So, setting up the infrastructure for refuelling them will be less of a problem. Already, hydrogen buses have been roaming the streets of Vancouver and Chicago. The World Bank believes such vehicles could play a role in helping to reduce urban smog in poorer parts of the world.

Phasing in hydrogen infrastructure is thus the first part of the puzzle. The oft-cited estimates of $100 billion or more for that are outlandish. That is because duplicating today’s petrol infrastructure, from day one, is simply not necessary. Experience with the introduction of diesel in America and unleaded petrol in Germany shows that even if only 15% of forecourts offer it, a new fuel can become widely accepted.

Directed Technologies, a consultancy based in Arlington, Virginia, argues that hydrogen can be produced in a distributed way economically. One option is to tap into the existing natural-gas grid to reform hydrogen. Firms such as International Fuel Cells of South Windsor, Connecticut, are now developing small reformers to do precisely that. These can be placed at petrol stations, supermarkets or even office blocks. Stuart Energy, a firm based in Toronto, is building tiny electrolysers for a car that can produce hydrogen from off-peak electricity. It aims to sell these for $2,000. Electrolysis is especially suited to the early years of hydrogen-powered cars because it is inherently scalable. Hydrogen electrolysis units make economic sense with only 25-50 cars sharing them. By contrast, the smallest hydrogen reformers need 300 users or so to be cost-effective.

Thus the economics of a hydrogen roll-out are not complete nonsense. Even so, explicit government supportmay still be needed. A new study by Dr Williams and Joan Ogden and Eric Larson, two colleagues at Princeton, suggests that, after the initial introduction, direct hydrogen fuel-cell cars will offer significantly lower costs and greater benefits to their users, as well as to society as a whole, than rival fuel-cell options. Unfortunately, the initial hurdle is so high that market forces alone may not spur the necessary investments. Dr Williams thinks the direct-to-hydrogen route will fail unless governments embrace zero-emission mandates like the Californian initiative. But if they do that, the Princeton group expects hydrogen fuel-cell cars to be successful. Within 20 years, they argue, the world could then enjoy extremely low vehicle emissions—and consumers would pay no more than they do today for transport.

That points to the most crucial factor of all in deciding the fate of fuel cells in transport—the actual consumer benefits. The clearest advantage fuel cells offer over the internal combustion engine is the potential for very low or zero emissions. But that may not be important to consumers. A more meaningful benefit is likely to be the fuel cell’s superior efficiency. Today’s internal combustion engines are notoriously inefficient, converting only about 15% of the heat content of petrol into useful energy. Even in their primitive state, fuel cells can already manage at least twice that efficiency. As fuel-cell technology matures, a rising level of efficiency will mean falling operating costs.

The switch to fuel-cell cars promises other differences that consumers may find attractive—a much quieter ride, a constant torque regardless of speed, a clean “engine off” energy source for power-guzzling electronics and a simpler transmission system requiring less maintenance. And, maybe, the fuel-cell car could even be a source of revenue for home-owners. Plugging it into the home electricity supply and transmitting the power generated by the car back to the grid while it sits in the garage could earn a profit on the energy market.

Contrary to conventional wisdom, going direct to hydrogen is not necessarily a folly. However, it is still possible that firms betting on such a technically superior option may get trumped in the marketplace by rivals peddling an inferior but more accessible technology—be that fuel cells with reformers in the tank or petrol-engined hybrids. Don Huberts, boss of Royal Dutch/Shell’s hydrogen division, says: “That is why everyone is placing bets on several horses. By no means is it clear today which the winner will be.” The race is on and whichever type of fuel-cell car is the eventual winner, the world will be a cleaner place.

Space-age soot
 

In order to power tomorrow’s cars, researchers are scrambling to exploit the hydrogen-absorbing properties of carbon

“THERE may be chimneys out there somewhere producing this stuff right now,” gushes Nelly Rodriguez, a researcher at Northeastern University in Boston. Her enthusiasm seems a bit odd, given that the object of her affection is a crumbly, black bit of soot that looks as though it has indeed come straight out of a chimney. Yet if Dr Rodriguez is right, this carefully synthesised bit of elemental carbon could help usher in an era of clean, hydrogen-derived energy.

Enthusiasm for the use of hydrogen as a fuel is growing by the day. The main reason is the pace of innovation in fuel cells, which are, in essence, batteries that use hydrogen to produce electrical energy efficiently, and without generating air pollution or greenhouse gases. There is one thorny question, however, that hydrogen enthusiasts have yet to answer satisfactorily: how exactly will this miracle fuel be stored? Hydrogen, after all, is a gas at room temperature, and is also flammable. Some experts argue that physical storage, as a compressed gas or in liquefied form, is the best solution. Others advocate chemical storage of hydrogen, in such fuels as methanol or cleaner petrol. Both approaches would require expensive investments in fuel infrastructure.

But there is another storage medium that could avoid these complications: carbon. A growing number of scientists now believe that carbon structures, called nanotubes and nanofibres, could provide a clean and efficient way to store hydrogen. This has unleashed a breathless and, at times, acrimonious race among scientists to find the most efficient structure for hydrogen storage, a competition that was on display a few days ago at a conference of the Materials Research Society (MRS) in Boston.

Elemental carbon had long been thought to exist in only three physical forms: graphite, diamond and an amorphous form, of which charcoal is an example. In recent years, however, scientists have discovered that carbon exists in several rather more unusual forms: as football-shaped molecules (consisting of 60 carbon atoms) known as “buckyballs”, and as related structures known as nanotubes and nanofibres. Imagine a sheet of carbon atoms laid out on a hexagonal grid, like chicken-wire. Nanotubes are like rolled up sheets, while nanofibres consist of tall stacks of small sheets in various configurations.

It has long been known that some solid materials, called metal hydrides, are capable of storing small amounts (about 1-2% of their own weight) of hydrogen at room temperature. Some metal hydrides are capable of storing more hydrogen (5-7% of their own weight) but do so only at impractical temperatures of 250°C or higher. Carbon nanotubes and nanofibres, however, seem to be able to absorb hydrogen well, even at room temperature. This opens up the prospect of soot-like materials, where each grain is a tiny carbon “sponge” able to hold hydrogen. Such materials could be used to make hydrogen cartridges that would slot into fuel-cell cars, making refuelling as simple as pulling into a filling station and swapping an empty cartridge for a full one.

Nobody really knows why carbon nanomaterials are good at storing hydrogen. Michael Heben of America’s National Renewable Energy Laboratory, a pioneer in the field, believes that it is something to do with the structure of the nanomaterials’ surfaces. Molecules of the gas seem to fit into pores in these surfaces, though exactly why they prefer some pores over others is unclear.

This idea is supported by the work, recently published in Science, of Mildred Dresselhaus of the Massachusetts Institute of Technology and a group of Chinese colleagues. The researchers synthesised a small quantity of nanotubes by passing high-voltage electrical arcs through graphite dust mixed with a carefully chosen catalyst—one of several competing methods. The nanotubes naturally cluster together into tiny bunches, and were found to be able to store 4.2% of their own weight of hydrogen. Crucially, the samples are easy to make, the results are reproducible and the process takes place at room temperature.

Although this is impressive, America’s Department of Energy has calculated that carbon materials will need to be able to store 6.5% of their own weight of hydrogen in order to make fuel-cell cars practical (defined as having a range of 500km, or 310 miles, between refuelling stops). Dr Dresselhaus says her analysis suggests that reaching this benchmark will be quite a challenge.

Which is why Dr Rodriguez’s results are so controversial. Last year, she reported that her group had synthesised a nanofibre material capable of storing 65% of its own weight of hydrogen. Her results met with widespread scepticism, for she has refused to reveal exactly how she synthesised the material. She and Terry Baker, her husband and collaborator at Northeastern University, insist that they need to keep the process secret for commercial reasons.

Other experts, many of whom turned up to the MRS conference last week, have been openly critical of the Northeastern researchers, who stayed away. But their remarkable claims have lit a fire under their rivals. In the months since, researchers have reported a series of advances. Seung Mi Lee of South Korea’s Kunsan University and her team announced a nanotube material at the conference that, they claimed, could store more than 14% of its own weight of hydrogen. Rivals from Singapore’s National University claimed to have achieved nearly 20% by doping nanotubes with lithium, though only at high temperatures. And a group from the Chinese Academy of Sciences claims to have achieved 10-13% using nanofibres.

Dr Rodriguez and Dr Baker remain unbowed. They insist that their results are reproducible, and that corporate clients who have tested their materials (under a vow of silence) have been satisfied. Part of their secret, they say, is in the catalyst that they use to grow their carbon nanofibre. A combination of carefully prepared powdered metals is gently placed in an atmosphere of ethylene, carbon monoxide, and hydrogen, and gently heated. The result, they claim in a paper that will appear this month in the Journal of Physical Chemistry, is a nanofibre material with an extremely high ratio of surface-area to volume. This means that far more hydrogen-friendly pores are exposed than with other materials.

So how do Dr Rodriguez and Dr Baker explain why their results are so far out of line with Dr Dresselhaus’s far more cautious prognosis? Experts such as Dr Dresselhaus, they say, assume nanomaterials are rigid; perhaps, they speculate, the molecular planes of their nanofibres expand “like a concertina” to accommodate more hydrogen. But, they admit, there is plenty that they do not know. “Our ultimate proof,” sniffs Dr Rodriguez, “is in the pudding.”

According to Dr Heben, most scientists, himself included, are still sceptical. Yet even he concedes that these carbon nanomaterials are so complex that it is difficult to predict their properties theoretically. Perhaps, he speculates, the explanation lies in entirely new and unanticipated kinds of hydrogen-carbon interaction. If so, then Dr Baker and Dr Rodriguez, now widely seen as either frauds or flukes, may come to be seen as the father and mother of the hydrogen age.

More about fuel cells

Iceland powers up
 

You can now buy hydrogen from a garage in Iceland
 

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LIKE a kettle near boiling point, the countryside outside Iceland's capital is perforated with vents and geysers letting off steam from the volcanic cauldron simmering just below the island's surface. This steam, together with hydroelectricity, provides 72% of Iceland's energy. But that is only the start. In a bid to become the world's first “hydrogen economy”, the government hopes to raise the figure to 100%.

This explains the excitement felt when a new pump was added recently to a service station just outside Reykjavik. Instead of petrol or diesel, it pumps hydrogen. Although this is not the world's first hydrogen filling-station, it is the first to be open to the general public. It is designed for vehicles that are powered by fuel cells, which react hydrogen with oxygen from the atmosphere to produce electricity. The other first is that the hydrogen itself is produced by the electrolysis of water—the electricity in question coming from all that environmentally friendly energy.

The only fly in the ointment is that there are, for the moment, no customers. But that will change when the country's bus fleet starts to convert to fuel-cell-powered vehicles in a few months' time. Eventually, the government hopes that private drivers will follow suit. In retrospect, Leif Eriksson, the Viking explorer who sailed from Iceland and discovered Greenland, got the names backwards. It is Iceland which is bidding to become the world's greenest country.

Hydrogen power

These fuelish things
 

AP

The fuel cell is enchanting politicians on both sides of the Atlantic. It is too soon, though, for them to dream of freedom from fossil fuels
 

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WHERE in the world can you find hydrogen? At first blush, that might seem a ridiculous question: hydrogen, after all, is the commonest element in the universe. The problem is that it is rarely found in its free state on earth. If you want to get your hands on some hydrogen, you generally have to strip it away from carbon, as found in hydrocarbon fuels, or from oxygen, as found in water. Either way, energy is required to produce it. And that, in a nutshell, is the big drawback lurking behind all the recent hoopla surrounding the charms of hydrogen energy.

The hoopla began at the end of last year, when the European Commission unveiled a grand, euro2.1 billion ($2 billion) “hydrogen vision”. Romano Prodi, the commission's president, even declared that he wanted to be remembered for only two things: the European Union's eastward expansion, and hydrogen energy. Now, George Bush, America's president, has produced his own $1.2 billion hydrogen plan (he even examined a hydrogen-powered car, and made sure he was photographed doing so). In speeches directed at the car industry in Detroit and, on February 10th, at the oil industry in Houston, Mr Bush and his team have been making the claim that the rise of the fuel cell will consign the internal-combustion engine to the dustbin of history. And if that were not enough, Democratic rivals in Congress—trying to keep up—have just unveiled their own hydrogen initiative.

Fuel cells are devices that work rather like batteries, converting chemical energy into electricity and heat. All fuel cells combine hydrogen with oxygen to produce power. These nifty power plants can be used to run anything from a mobile phone to an office complex. Their greatest attraction is that they can do all this without generating emissions any more harmful than water vapour.

The catch, of course, is that it is first necessary to find a source of hydrogen. If renewable energy is used to split water into hydrogen and oxygen by electrolysis, then the energy produced by a fuel cell is genuinely emission-free. But if energy from a hydrocarbon such as petrol or coal is used, there will still be some unwanted emissions. That applies even if the route taken is steam reformation, in which the hydrocarbon is reacted with water vapour to liberate the hydrogen in both, rather than being used to make electricity for the electrolysis of water.

The emissions from steam reformation, though, are less than those created when the same amount of hydrocarbon is burned in today's combustion engines. This is because fuel cells produce electricity efficiently, without combustion. And, if techniques for capturing and “sequestering” the carbon dioxide produced by hydrocarbons are perfected, it would make hydrogen from fossil fuels a great deal cleaner still.

Europe and America do not see eye to eye on the question of how best to generate hydrogen. Europe is putting more emphasis on renewables; America, by contrast, is keen on the possibility of deriving hydrogen from fossil fuels.

At the moment, using renewables is an expensive way of generating hydrogen (see table). So why is Europe heading in this direction? Alessandro Ovi, one of Mr Prodi's advisers, explains that Europe's push for hydrogen is motivated largely by a desire to meet its commitments to cut greenhouse gases under the Kyoto treaty on global warming. Accordingly, the EU has adopted demanding targets for increasing the share of renewable energy to 22% of the region's electricity supply by 2010, up from about half that today.

Such a target for renewable energy sounds pretty green, but there is a snag: wind and solar energy are intermittent, and unlike other commodities—be they bananas or natural gas—there is no good way to store electricity for later use. No way, that is, unless you use renewable energy to produce hydrogen, and store this instead. It can then be used when the power grid is facing peak demand and the price of energy thus increases. Dr Ovi thinks hydrogen could transform the economics of renewables and play an essential role in the EU's clean-energy strategy.

Mr Bush's plan pushes instead for hydrogen via fossil fuels, because greenery is not the only attraction of fuel cells. Mr Bush insists that hydrogen is a good way to bolster his country's “energy independence” from Middle Eastern oil. Hydrogen can be made from America's plentiful supplies of coal, as well as from locally produced biomass and renewable energy, says John Marburger, Mr Bush's top science adviser. Thus, America's reliance on oil from fickle foreign regimes will decline. That vision of energy independence through fossil hydrogen is also gaining popularity among the leadership in coal-rich but oil-starved China.

Does that mean the American approach is ungreen? Not necessarily. Even if fossil fuels were used to produce hydrogen without sequestration, fuel-cell-powered cars would still produce zero local emissions on roads. (Wags call this “drive here, pollute elsewhere”.) Further, hydrogen is likely to be produced by some green sources anyway: in the Pacific north-west, hydro-electric power is dirt cheap at night, and on the windswept Great Plains renewables or biomass may prove more economic than fossil fuels.

If America pursues its hydrogen vision by using fossil fuels with techniques such as sequestration, a technology Mr Bush has repeatedly applauded, its hydrogen embrace will indeed be greener than green. What is more, if Big Oil also gets behind hydrogen—as it is now starting to do thanks to the new push from the Texan oilman in the White House—the thorny question of where you can find hydrogen could one day become very simple to answer. Right at your corner petrol station.

Miniature fuel cells

Batteries not included?
 

Will tiny versions of the fuel cells now being developed for cars soon power laptop computers too?
 

Get article background

AS VIDEO telephony, broadband internet links and other high-powered features are added to laptop computers, personal digital assistants (PDAs) and mobile phones over the next few years, the energy demands of these devices will soar. The Samsung Advanced Institute of Technology, the research arm of the chaebol of that name, estimates that such upgraded portable devices will require power sources with at least 500 watt-hours per kilogram of energy stored in them. Lithium-ion batteries, today's best, can manage half that, but even the most optimistic estimates suggest that only a 30% improvement could be squeezed out of such batteries.

But there may be an alternative. Miniature fuel cells, which generate electricity by reacting hydrogen with oxygen, can do much better than batteries—at least in a laboratory. The question is whether they can ever do so in the real world. This was the subject of a conference organised last week in New Orleans by the Knowledge Foundation.

The key to making fuel cells small is to replace the hydrogen—or, rather, to deliver it in a non-gaseous form, since it is hardly practical to fit portable electronic devices with pressurised cylinders. In the long run, there may be ways round this, for instance by absorbing the gas in metal hydrides or carbon nanotubes. But in the short term the solution seems to be to deliver the hydrogen as part of a hydrogen-rich compound, such as methanol. This is a liquid, which means it is easy to handle. Sachets of methanol fuel, purchased at newspaper kiosks, rather like refills for cigarette lighters, could be inserted with little fuss into electronic devices.

There are two ways to get the hydrogen out of methanol in a way that a fuel cell can use. One, being pursued by several companies, notably Motorola, is called reformation. This attempts to replicate in miniature the complicated networks of piping, heaters, vaporisers, heat exchangers and insulation that the petrochemical industry uses to extract hydrogen in bulk from methane, a chemical one oxygen atom different from methanol. That is hard—doubly so, since reformation works best at 200°C.

There are some variations on the theme, but most of those building miniature methanol reformers use an approach not much different from the one used to make circuit boards for computers. They laser-drill holes into tiny ceramic wafers to guide the flow of fluids. Then they stack these one on top of another, like layers of a sandwich, sinter them together at a temperature of 800°C, and laminate them. Presto, a mini-chemical plant.

The alternative to reformation is to feed the methanol directly into the cell, and rely on a catalyst to break it up at the electrodes, where the hydrogen is separated into its constituent electrons (which form the current that the cell produces) and protons. The trouble with this approach is that pure methanol tends to get everywhere, and thus wrecks the cell. Diluting it with water reduces this problem, but also reduces the power output.

At least one firm, however, thinks it can get round this. MTI MicroFuel Cells, based in Albany, New York, boasts some top researchers poached from the Los Alamos National Laboratory in New Mexico. One of them, Shimson Gottesfeld, told the conference that the firm has developed a cell that can use undiluted methanol. This, he claims, allows it to achieve more than three times the energy density of lithium-ion batteries.

Dr Gottesfeld was reluctant to go into details. But the secret seems to lie in some clever internal geometry, which eliminates the need for pumps. That, in turn, reduces the tendency for methanol to go where it is not wanted. However the trick is performed, though, MTI has working prototypes. It also has a contract. Its cells are due to go to market next year as part of a hybrid power-pack (that is, one which also involves batteries) being built by a large equipment firm called Intermec for use in handheld computers.

Better ways of handling methanol are not the only possibility, though. Another is to find further alternatives to elemental hydrogen. That is the route chosen by Medis Technologies, an Israeli-American firm. Its fuel is a mixture of glycerol and sodium borohydride. These react in the presence of a platinum and cobalt catalyst, generating protons and electrons in the same way as methanol—or, indeed, pure hydrogen.

Although many at the conference were sceptical, suggesting for example that the Medis cell works only when it is standing up, the firm remains bullish. Gennadi Finkelshtain, Medis's principal scientist, acknowledges his device's sensitivity to its orientation, but insists that he has a solution in the works. The fact that he has persuaded General Dynamics, a big defence contractor, to form a partnership with him to supply the American armed forces with the new device suggests that the problems cannot be too great. Medis showed off a prototype recharger for a “ruggedised” military PDA that it says it will start manufacturing next year.

None of this adds up to a revolution in portable power, of course, but it is a tantalising start. As so often with new technologies, military applications are important drivers. The American army is keen to have more energetic and longer-lived power sources for such things as climate-controlled bodysuits, advanced mobile-communications equipment and more sophisticated sensors. But consumers will soon be able to purchase lightweight fuel cells, too. Even though they are unlikely ever to be compact enough for use in mobile phones, they could act as portable chargers for such phones. And in devices that are only a bit larger, they could, indeed, end up replacing batteries.

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