Phil Wrigglesworth

DURING a keynote address at the Consumer Electronics Show in Las Vegas in January, the boss of General Motors (GM), Rick Wagoner, unveiled the Cadillac Provoq, a new hydrogen fuel-cell concept car. With a drivetrain emitting only water vapour, a 300-mile range and a top speed of 160kph (100mph), the vehicle, said Mr Wagoner, represented “the promise of truly sustainable transportation”. It was a promise that sounded vaguely familiar.

A decade earlier, in 1998, Mr Wagoner's predecessor, Jack Smith, told the Detroit auto show that GM had a plan to produce a production-ready fuel-cell vehicle “by 2004 or sooner”. That same year, Ford's incoming boss, Jacques Nasser, said that he saw fuel-cell cars as being a viable alternative to petrol cars for many people during the course of his career (he was replaced in 2001). And as recently as 2004 California's governor, Arnold Schwarzenegger, rhapsodised about “hydrogen highways” all across the state by 2010.

Ever since the writings of Jules Verne in the 19th century, the idea that hydrogen would one day displace fossil fuels has attracted many adherents. Most recently, the dream has centred on hydrogen-fuelled cars, powered by fuel cells—electrochemical devices that combine stored hydrogen with atmospheric oxygen to generate electricity and water vapour. (This means the car produces no CO 2 emissions directly, but whether it is emission-free overall depends on the source of the energy used to produce the hydrogen. The hydrogen is more of a temporary store of energy from other sources than a fuel.)

But the promise of hydrogen-powered personal transport seems as elusive as ever. The non-emergence of hydrogen cars over the past decade is particularly notable since hydrogen power has been a darling of governments worldwide, which have spent billions of dollars in subsidies and incentives to make hydrogen cars a reality.

Proponents of hydrogen fuel-cell technology point to advances that have been made in the size and efficiency of fuel cells, and the appearance of a smattering of hydrogen filling-stations in a few parts of America and Europe. Carmakers are also keen to publicise the handful of trials that are providing them with data on the real-world performance of hydrogen fuel-cell cars.

This year GM and Honda are deploying a few such vehicles, which are being put into the hands of carefully selected drivers. GM has recruited celebrities, journalists, businesspeople and members of the public to test a fuel-cell version of its Chevrolet Equinox. Honda has started leasing small numbers of its FCX Clarity, which it describes as a “production model” to drivers in California.

But aside from these high-profile, low-volume projects, the logistical, technological and economic problems facing hydrogen fuel-cell cars mean that they are very unlikely to make it to market any time soon. One thing holding back hydrogen vehicles is a chicken-and-egg problem: why build cars if there is nowhere to fill them up, or hydrogen filling-stations if there are no cars to use them?

Just around the corner, honest

Earlier this year GM said that despite its own rapid progress on hydrogen fuel-cell vehicles, America's energy industry and government were lagging behind when it came to building hydrogen filling-stations. Mr Wagoner even said that this might mean that hydrogen cars would be deployed elsewhere first—such as China. Honda, meanwhile, is covering itself by developing a Home Energy Station, which drivers of fuel-cell vehicles can use to make their own hydrogen at home, by tapping into the domestic natural-gas supply.

“The real challenge as we move toward retail is that we need to change the nature of the fuelling system,” says Catherine Dunwoody, executive director of the California Fuel-Cell Partnership (CaFCP), an industry body. She says that in order for fuel-cell cars to become a reality, hydrogen filling stations have to move from serving fleets of corporate or municipal vehicles to being able to serve private customers.

Phil Wrigglesworth

Duncan Macleod, vice-president of Shell Hydrogen, admits that there has been a “disconnected debate” between the carmakers and the fuel companies, but says discussions with carmakers over the past year have been much more productive. He says Shell's solution to the chicken-and-egg problem is a series of local mini-networks, each comprising hundreds of fuel-cell vehicles and at least two refuelling stations. Despite the grand vision, however, Shell currently has only six hydrogen filling-stations worldwide. BP, another early advocate of hydrogen, is also retreating from its early bullishness: it closed its only hydrogen filling-station in Britain in 2007 and has recently started to switch its focus towards biofuels, rather than hydrogen, as a near-term replacement for petrol.

One thing on which carmakers and energy firms do agree is the need for government funding and the appropriate public policies in order to promote the commercialisation of hydrogen vehicles. Governments in Europe and America have been more than willing to oblige. Since President George Bush launched his Hydrogen Fuel Initiative in 2003, America's Congress has provided over $1 billion for hydrogen research—though not everyone approves. The Bush administration's enthusiasm for hydrogen has worked “to the detriment of nearly all other renewable energy sources,” says Severin Borenstein, director of the University of California Energy Institute at Berkeley.

In Europe the flow of funding for hydrogen research has been slower to come, but no less substantial. In May the European Parliament approved €470m ($730m) for a fuel-cell and hydrogen initiative, a sum it expects the private sector to match. The establishment of the National Organisation for Hydrogen and Fuel-Cell Technology in Germany, a joint venture between German industry and government, recently put a further €500m into the pot.

How much more investment is needed to make mass-produced hydrogen cars a reality? According to a recent study by Oak Ridge National Laboratory, sponsored by America's Department of Energy (DoE), public funding of $10 billion would be required to get 2m hydrogen fuel-cell cars onto America's roads by 2025, rising to $45 billion for 10m cars. A report issued by America's National Academy of Sciences in July was less optimistic, estimating that $55 billion of government investment would be needed to put just 2m hydrogen cars on the road by 2023. And both reports assume that the technology will get a lot cheaper: the Oak Ridge study assumes it will be possible to make fuel-cell vehicle systems in quantity at a cost of $45 per kilowatt of output by 2010, and $30 per kilowatt by 2015.

This is ambitious. Although fuel-cell costs have dropped by 65% since 2002, according to the CaFCP, today's fuel cells cost around $107 per kilowatt. Are sudden cost reductions around the corner? Not according to one of the pioneers of fuel-cell technology, Ballard Power Systems, a Canadian supplier of fuel-cell systems to a range of carmakers. In November 2007 it sold its automotive fuel-cell division to Ford and Daimler after a decade of losses, citing the “realities of the high cost and long timeline for automotive fuel-cell commercialisation” for its exit from the business.

These realities are also being noticed outside the business world. In March this year the California Air Resources Board, an agency of California's state government and a bellwether for state governments across America, changed its requirement for the number of zero-emission vehicles (ZEVs) to be built and sold in California between 2012 and 2014. The revised mandate allows manufacturers to comply with the rules by building more battery-electric cars instead of fuel-cell vehicles.

The trouble with hydrogen

Even if the network of hydrogen filling-stations can be built, and the technological advances needed to reduce the cost of fuel-cell vehicles can be made, a huge problem still remains: the production and delivery of hydrogen in large quantities. The Oak Ridge study says the two most promising ways to produce hydrogen cheaply in the near term are to make it from natural gas (through a process called “steam reforming”) at the filling stations themselves, or to make it from gas derived from biomass or coal at large, centralised plants, and then deliver it by lorry or pipeline.

Hydrogen sceptics point out not only the large capital costs associated with the production, transportation and storage of hydrogen, but also the availability of far more viable alternatives. Hydrogen is “just about the worst possible vehicle fuel”, says Robert Zubrin, a rocket scientist and the author of “Energy Victory”, a book on the post-petroleum future. Even if the requisite gains in fuel-cell technology are achieved, he says, the fuel-cell cars of the future should run instead on methanol, which has a higher energy-density than hydrogen and can be stored and transported much more easily.

Furthermore, steam reformation of natural gas is far from a zero-emissions solution, undermining the whole rationale of hydrogen cars in the first place. According to America's National Renewable Energy Laboratory, producing a kilogram of hydrogen by steam reformation generates emissions equivalent to 11.9kg of CO 2 . Given that the Chevy Equinox fuel-cell vehicle can travel 39 miles on a kilogram of hydrogen, and the FCX Clarity can travel 68 miles, powering these cars using hydrogen produced by steam reformation would result in emissions of 305 and 175 grams of CO 2 per mile respectively. By comparison, today's petrol-electric Toyota Prius hybrid produces tailpipe emissions of around 167 grams per mile, and many small petrol cars achieve similar results.

Even hydrogen optimists concede that the reliance on hydrogen from steam reformation is not viable in the long term. “If all we can do is make hydrogen from gas, we shouldn't even start the journey,” says Mr Macleod at Shell. Instead, he says, the solution to large-scale hydrogen production lies in using renewable electricity to extract hydrogen from water via electrolysis. Others suggest making hydrogen using off-peak electricity or nuclear power. But it would surely be easier simply to use this energy to charge the batteries of all-electric or plug-in hybrid vehicles.

Yet for advocates of fuel-cell cars, hope springs eternal. The CaFCP sees tens of thousands of fuel-cell vehicles on the road by 2017; Shell predicts that mass roll-out of fuel-cell vehicles is “absolutely achievable” by 2020; and the DoE maintains that fuel-cell cars will be “practical and cost-effective” by the same year. BP is cagier, predicting that it will be 2030 before a significant number of fuel-cell vehicles are in use. In other words, claims that hydrogen will be the automotive fuel of the future are as true today as they ever have been.