Fuel cell buses in fast lane to maturity

Fuel cell-powered buses will soon prove more cost effective than their diesel counterparts as manufacturing costs continue to fall, reliability improves and the price of diesel continues to climb.

That is the prediction of Jan van Dokkum, president of UTC Power, the fuel cell division of engineering conglomerate UTC, which this month celebrated the largest US order yet for the company's hydrogen bus fuel cells.

Californian bus operator AC Transit has agreed to buy a minimum of eight of UTC Power's 120 kW PureMotion Model 120 fuel cell systems, and Van Dokkum expressed confidence that the firm would exercise its option to procure a further 13 of the systems.

He added that the company was also expecting to see increased interest in the technology from across California. "AC Transit in Oakland has placed this order, but they are working with other operators across the state on fuel cell projects," he said. "The zero-emission vehicle legislation [which was introduced in California recently and requires a proportion of vehicles to be emission free from 2012] covers buses so there is pressure on firms to look at these vehicles. "

As demand for fuel cell-powered buses continues to climb, Van Dokkum is confident that the technology is now mature enough to compete with incumbent diesel engine buses. The company noted that while the first-generation fuel cell buses trialled by AC Transit came with a 4,000-hour warranty, the latest fuel cells will be offered with a warranty period of up to 10,000 hours of operation.

"I don't mind admitting I was a bit nervous about putting the first-generation buses in commercial circulation," said Van Dokkum. "But they have proved far more reliable than expected, particularly when you consider tha t the duty cycle of a bus is very heavy and it has to transport a lot of weight while repeatedly stopping and starting."

He added that improvements to the hybrid engine – designed to make the battery more resilient to the repeated charging and discharging it undertakes on any journey – meant that the latest version of the technology is expected to prove at least as reliable as diesel engines.

The technology is also fast approaching a point where it can compete with diesel buses on cost, according to Van Dokkum. "The first generation of the bus cost $3m (£1.5m), but consistently delivered fuel economy that was over 70 per cent better than a control fleet of diesel buses," he explained. "The second generation will cost $2m, which will bring the full lifecycle costs close to the same as diesel buses when fuel costs are taken into account. Once we get volume production up and running we hope to get the price down to $1m to $1.2m, at which point we will be the more cost-effective option for the operator, while also delivering quiet vehicles with zero ground-level emissions."

The AC Transit buses have delivered a 50 per cent reduction in carbon emissions compared to diesel buses by sourcing hydrogen made from natural gas, but Van Dokkum insists fully zero-carbon buses are feasible, citing a similar trial in Connecticut that uses hydrogen manufactured using hydroelectric power to run the buses.

"Ultimately, we envisage a scenario where the transport and waste management offices of major cities are integrated," he said. "They could then use the methane captured from landfill sites to extract hydrogen and run their fleets. "