Hard sell for green cars

Fuel cell cars are regarded by many as the answer to all our environmental concerns but so far all we have seen are a few prototypes and a few buses.

The achievements of the fuel cell industry —

in particular — has been impressive; the ratio of kW/£ has improved dramatically over the past 15 years or so. In many respects the fuel cell car is competitive with the internal combustion engined car even today. The problems are in vehicle integration, materials cost, fuel supply and production, manufacturability and infrastructure.

The vehicles have come a long way. Not too many years ago, a panel van was the smallest possible fuel cell vehicle, as the system took up so much room. During the 1990s there was a rapid reduction in size and today's experimental fuel cell vehicles look uncannily like conventional internal combustion powered vehicles. In practice, the system still takes up a lot of space. The 'plumbing' of these systems is complex, and much work needs to be done to improve this.

One outstanding problem is the fuel cells' need for platinum. This precious metal is also used in catalytic converters. It is relatively rare and reserves could even be stretched by the projected production volumes of cars if they were just petrol-powered and catalyst-equipped. However, a fuel cell system for a car needs at least twice as much of this metal as a catalytic converter. The industry and its suppliers are looking at ways of reducing the fuel cell's platinum dependency. If they fail, the required volumes can't then be achieved; in fact there may not be enough even to supply converters to all the world's internal combustion cars for much more than 15 years.

Fuel supply is another issue to be resolved. Most automotive fuel cells run on pure hydrogen. On Earth it only occurs bound with oxygen in the form of water, or bound with carbon in a range of hydrocarbons. In each case, some process is needed to separate the hydrogen from these other elements and this requires energy, with attendant carbon emissions if fossil sources are used, such that the total lifecycle impact of hydrogen does not always make it the most environmentally optimal fuel.

On-board reforming of hydrogen from hydrocarbon fuels such as methanol or even petrol has also been suggested. This would obviously add weight and complexity to the vehicle and would also use energy.

It would, however, remove the need for large hydrogen production facilities and for a hydrogen distribution infrastructure. Recent experiments with compressed hydrogen have at least shown that by using very high pressures a sufficient amount of fuel can be carried in a car to give it an acceptable range of about 483km. This shows the industry is achieving improvements in the move towards practical fuel cell cars at a steady rate.

Much has also been made of the need to replace or replicate the existing fuel supply infrastructure with a hydrogen version.

The building of a dedicated infrastructure is expensive; it has been estimated at $5,000 (£2,500) per car. There is also a chicken-and-egg situation in that few fuel cell vehicles would be sold without a fuelling infrastructure, while no commercial organisation would build an infrastructure without some guarantee of demand.

Various automotive fuels are now offered in markets around the world. Adding hydrogen as an additional fuel is often difficult on a crowded forecourt with a fixed number of storage tanks. With only five per cent of new car sales being hydrogen-powered, this is indeed difficult to justify.

However, in British Columbia and California there have been proposals for 'hydrogen highways' — corridors where hydrogen availability would be guaranteed at regular intervals.

Clearly some government support would be required. However, it has also been suggested that hydrogen does not need to be distributed in the way petrol or diesel are today. Rather than onboard reforming, some are now suggesting this reforming — extracting hydrogen from a feedstock — can be done by larger units set up alongside fuel stations and linked to one or more pumps on the forecourt for the supply of pure hydrogen to fuel cell cars. In this way, no significant change in the fuel distribution system would be needed.

The total number of vehicles produced worldwide today is about 60 million. It is safe to assume that with China, India, Indonesia and others all in the fray by 2015, this number will have grown to nearer 80 million, if not more. The market share of newly registered fuel cell vehicles by then will therefore be a maximum of one eightieth of the annual global market.

As they have businesses to run, neither the Canadians at Ballard, nor the Japanese are likely to significantly increase fuel cell production capacity before there is a clear sign of demand. Once this is apparent the lead-time for another half million capacity facility will be at least a year, if not more.

Let us assume therefore, that by 2020 we will have a global automotive fuel cell production capacity of four million stacks. If we keep to our global vehicle production figure of 80 million by then we find that five per cent of vehicles made can be fitted with a fuel cell.

Obstacles to the introduction of hydrogen fuel cell vehicles are being dismantled by technological and conceptual solutions. If this trend continues, we can have commercial fuel cell cars appearing on the roads of at least some parts of the world in the next decade.