Picture the scene: you\\$quot;ve finally got your hands on that dream motor. Eager to take her out and play with some of those hi-tech gadgets you\\$quot;ve splashed out on, your first stop may well be the nearest gas station. Driving in, you glide past the same colour coded-pumps that have \\$quot;“ until today - breathed life into every vehicle you\\$quot;ve ever owned: red for leaded, green for unleaded, black for diesel. The holy trinity. Ignoring these you pull up next to something new. It\\$quot;s about the same size as the other pumps - possibly blue - and its design is dominated by one word - Hydrogen.

You get out, remove the petrol cap from your car, insert the nozzle and stand by as the pump\\$quot;s liquid contents are pumped into your vehicle. Sounds simple, but could this vision of the future ever become reality for most car users?

Canada\\$quot;s hydrogen highway
In Canada work is well under way on the construction of a network of hydrogen stations \\$quot;“ known as a hydrogen highway - that could eventually be visited by mass produced-fuel cell vehicles looking to fill up at stations all over the country.

As well as three stations operating in the province of British Columbia, there are four others at sites in Ontario, and yet more in various stages of construction in Alberta, Saskatchewan, Manitoba, Quebec, and Prince Edward Island. It\\$quot;s the most elaborate programme of its type anywhere in the world.

Meanwhile, in Europe, oil and gas giants such as BP and Shell, along with car manufacturers Daimler Chrysler and Ford, have been working together on the design and manufacture of fuel cell vehicles for more than two decades. Their work is being displayed on a regular basis in demonstration projects at purpose-built sites in London, Berlin, Barcelona and Porto.

As well as providing car manufacturers with the perfect opportunity to showcase their new fuel cell vehicles, these projects also allow companies such as BP, BOC and Linde to explore different ways of generating hydrogen for mass-market consumption, as well as looking into possible design schematics for widespread refuelling facilities in Europe.

At present, most of these projects involve public transport vehicles such as buses and lorries rather than passenger cars, for they travel a predictable route where you can refuel at a certain point.

Hydrogen still in its infancy?
Despite this, John Carolin, global director of sustainable energy at BOC, believes that research into hydrogen-fuelled technology is still very much in its infancy. \\$quot;We\\$quot;re not going to see a revolutionary change that in fifteen or twenty years is going to totally change what everybody\\$quot;s doing. It\\$quot;s going to be much slower than that,\\$quot; says Carolin.

\\$quot;I think that in 2030 hydrocarbons \\$quot;“ petrol and diesel \\$quot;“ will still account for the majority of energy used in transportation, but I\\$quot;d expect that hydrogen will be a significant portion of what\\$quot;s used.\\$quot;

However, Dean Millar, programme director for renewable energy at Exeter University, is not so optimistic. \\$quot;I would say fifty years at least,\\$quot; says Millar. \\$quot;Too far in the future for hydrogen to have a substantial effect on reducing carbon emissions for when they need to be reduced.\\$quot;

David Nicholas, spokesperson for BP, is more cautious in specifying a date for mass-market production. \\$quot;It\\$quot;s an option I think at the moment, he says. \\$quot;But whether it ends up becoming a mainstream replacement for transport, who knows.\\$quot; Instead, Nicholas is quick to defend the continued role of fossil fuels by highlighting the general drop in both sulphur and benzine emissions. \\$quot;You\\$quot;ve got to remember what happened to the transport fuels we use already. The levels of pollution in terms of air quality from the petrol and diesel we use on a daily basis has drastically fallen over the past fifteen to twenty years.\\$quot; He adds: \\$quot;Engines have got more efficient; technology has developed and fuels have got cleaner and cleaner.\\$quot;

But despite Nicholas\\$quot; support, fossil fuels can never hope to match the positive impact hydrogen could have on our environment. \\$quot;It\\$quot;s clear that hydrogen is a possibility and clearly it has environmental benefits,\\$quot; he says. \\$quot;When you put hydrogen through a fuel cell all you have as a bi-product is water. It doesn\\$quot;t burn harmful emissions.\\$quot;

Fuel cell technology is considered to be as about as environmentally sound as you can get; yet despite this many consider hydrogen to be far from perfect.

Millar believes that in its gaseous state hydrogen is not dense enough to work as an effective fuel. \\$quot;Hydrogen as a gas is needed in big volumes,\\$quot; he says. \\$quot;So if you\\$quot;re going to increase the energy density in terms of volume terms - which you need to do in a car, you need a lot of energy in a relatively small space \\$quot;“ your fuel tank.\\$quot;

Millar adds that in order to make it work \\$quot;you have to liquefy the gas so that a kilo of hydrogen gas actually has an energy density comparable to that of the current fossil fuels we are using. If it\\$quot;s not the car won\\$quot;t be as powerful and won\\$quot;t be able to travel as fast.\\$quot;

The problem with this is that liquefying H2 gas requires valuable energy. \\$quot;Essentially, you need to compress the gas and then cool it very quickly - and that in itself takes energy,\\$quot; says Millar.

\\$quot;For your average car user, a more pressing concern is whether or not hydrogen is actually safe to use?

\\$quot;Any fuel has safety issues associated with it; almost by definition because it\\$quot;s a source of energy,\\$quot; says Carolin. \\$quot;In a way, hydrogen is no different from gasoline or diesel in that you just have to use it in a safe way. I don\\$quot;t think that inherently it\\$quot;s any less safe than the products we\\$quot;re already using today. It\\$quot;s just got to be done right.\\$quot;

However, Millar disagrees. \\$quot;Safety-wise there are some big issues in terms of the widespread role out of hydrogen as a fuel,\\$quot; he says. \\$quot;It\\$quot;s probably the most explosive gas you can have. Can you imagine going along to a gas station and
filling up with something that if there\\$quot;s any spark will detonate?\\$quot;

Hydrogen fuel technology, feasible?
For Millar the development of hydrogen-fuelled technology is simply not feasible - as a commercial product - in the kind of timescale that\\$quot;s been discussed. \\$quot;It\\$quot;s a fantasy in my view to imagine that hydrogen will have - or make - any significant inroads into reducing carbon emissions on the road; they won\\$quot;t even get to one per cent in twenty years, I would say.\\$quot;

Millar\\$quot;s solution to the problem posed by carbon emissions is fairly straight forward on paper. \\$quot;Travel less,\\$quot; he laughs. \\$quot;The bus still probably works out the more efficient way to travel in energy terms, but we need more people on them,\\$quot; he says. \\$quot;When there are more people on the buses there will be more buses and more routes and it will be easier to use a bus.

Eventually things will get bad enough and everybody will realise, oh God, we should have done this years ago,\\$quot; sighs Millar. \\$quot;Possibly by then it will be too late.\\$quot;

DaimlerChrysler is the parent company that owns Mercedes-Benz. Since 1994 its engineers have been sounding out the opportunities presented by a hydrogen-based fuel cell with the development of several concept vehicles. The first of these was the NECAR 1 van \\$quot;“ the first in a series of five from the NECAR family. The fuel cell weighed 800 kilograms, leaving only enough room for the driver and a front-seat passenger. It was described at the time as being little more than a \\$quot;˜laboratory on wheels.\\$quot;

Six years and four NECAR vehicles later, we saw the unveiling of the fifth and final member of the NECAR family in 2000. With earlier models revealing both a gradual reduction in the size of the power system and huge advances in vehicle performance, the NECAR 5 operated by using methanol as a hydrogen storage medium. In 2002 this Mercedes Benz A-class vehicle smashed the endurance record for fuel cell vehicles. It covered the 3,260 miles from San Francisco to Washington, crossing both the Sierra Nevada and the Rocky Mountains en route \\$quot;“ conquering altitudes of up to 8,860 ft.

In recent years DaimlerChrysler has unveiled several new fuel cell vehicles, such as the Mercedes-Benz A-class F-cell in 2002, and the Mercedes-Benz Citaro the following year. The F-cell was the world\\$quot;s first small-series automobile to use fuel cell drive, while the Citaro is a bus that\\$quot;s powerful enough to accommodate seventy people - with an operating range of 125 miles.

At last year\\$quot;s Geneva Motor Show, DaimlerChrysler unveiled the Mercedes-Benz B-class F-Cell, thus extending its range of fuel cell vehicles to include the category of sports tourers. As well as designing and operating test vehicles around the world \\$quot;“ more than one hundred at the moment \\$quot;“ the group is also heavily involved with both BMW and General Motors in developing hybrid drive systems. The goal here is to design petrol cars that are as efficient as diesels - and diesel cars that are as clean as petrol cars. The plan to combine petrol and diesel engines could lead to a substantial drop in harmful emissions without sacrificing high-level comfort. Work is ongoing at the Hybrid Development Centre in Troy, Michigan \\$quot;“ a site owned jointly by DaimlerChrysler, BMW and General Motors. Last year, Mercedes-Benz unveiled the first test cars to feature these hybrid systems - Direct Hybrid and Bluetec Hybrid.

Serving over two million customers in fifty countries, BOC owns almost a hundred hydrogen plants around the world. By distributing vast quantities of hydrogen to customers \\$quot;“ such as DaimlerChrysler - gas companies such as BOC are vital to hydrogen\\$quot;s chances of succeeding on a mass scale. However, with research into commercially viable hydrogen fuelled cars still in an early development stage, BOC is currently concentrating on other markets away from cars.

\\$quot;I think there are other segments of the market which will adopt hydrogen much sooner than cars - such as forklift trucks,\\$quot; says Carolin. \\$quot;Our goal is to make sure that we\\$quot;re positioned for those earlier markets in the short to medium term while at the same time positioning ourselves for participating in the markets which will evolve in that longer timescale.\\$quot; He adds, \\$quot;We\\$quot;re not waiting for mass-market cars\\$quot;- to develop \\$quot;“ in the next fifteen to twenty years; we think there are other things that can happen much sooner.\\$quot;

As well as operating large fleets of liquid tankers and tube trailers for hydrogen distribution, BOC is also involved in developing manifolded cylinders for moving much smaller quantities of hydrogen; these are built specifically for fuel cell applications.

Like BOC, BP already produces a huge amount of hydrogen at its refineries around the world. Its efforts are geared toward the production, distribution and retailing of hydrogen for the global market.

BP is also involved in building demonstration refuelling stations in cities such as Barcelona, Berlin, and Perth, Australia, and has also been helping to develop the infrastructure for a passenger refuelling site in Los Angeles. One of these schemes is the EU initiative CUTE \\$quot;“ Clean Urban Transport for Europe. BP is providing the fuel for the project, which is running in nine cities. One of those is London, where three buses are filling up at a hydrogen pump in a refuelling station in the east of the capital.

Both DaimlerChrysler and BOC are assisting BP in its research, with the latter providing much of the technology. And with the recent announcement that the scheme will continue in seven of the nine cities for a further twelve months \\$quot;“ including London, David Nicholas quick to point out the benefits.

\\$quot;It gives us the chance to try out different technologies, potentially for generating hydrogen and possibly options on what a refuelling facility might look like,\\$quot; he says. \\$quot;It\\$quot;s learning by doing, but on a clearly defined scale.\\$quot;