Driving hydrogen fuel forward

BMW's 7 Series hydrogen fleet.

The search for improved fuel-efficiency is a balancing act for carmakers - no point having a high-tech car that runs on the smell of an oily rag if it drives like a milk vendor's cart.

Honda is balancing the ongoing development of its hydrogen-powered FCX Clarity with the sedan's driveability. It has pared down the size of the fuel stack, all the time mindful of what effect a smaller fuel cell will have on the car's overall performance.

So far, so good. The redesigned fuel-cell stack is 20 per cent smaller and 30 per cent lighter but more powerful than that used in the previous FCX concept.

The new fuel stack also works differently.

The hydrogen and the water formed in generation now flows vertically. Previously, it flowed horizontally. Honda says the design uses gravity for better water drainage, a key to high-efficiency fuel-stack performance.

The result is stable power generation under a broad range of conditions and higher output from a smaller package, a far cry from earlier fears about the volatile gas. Carmakers see petrol-electric hybrids as the medium-term key to reducing exhaust emissions. But hydrogen is still in the race.

Israeli scientists claim they are bringing it a step closer to widespread use as a fuel by putting it in much smaller, lighter containers. Rather than using metal or composite cylinders of compressed gas, the hydrogen is packed into glass filaments which, once out of the lab, will be only slightly thicker than a human hair.

These 370 glass capillaries are bundled into a glass tube called a capillary array, about the width of a drinking straw. The scientists say 11,000 such arrays will fuel a car for 400 kilometres, take less than half the space and weight of tanks currently installed in the few hydrogen cars now available.

"We have shown new materials that can store more hydrogen than any other system," says Dan Eliezer, chief scientist of C.En Ltd., the company based in Geneva, Switzerland, where the Israelis are developing their invention.

The scientists make no attempt to improve the standard fuel cell, which is not much different today from when it was invented more than 150 years ago. A fuel cell makes electricity from chemical reactions involving hydrogen and oxygen, producing only water vapour as a byproduct.

The fuel cell can be compared with a standard car's engine, while the capillary arrays would be comparable to the petrol tank.

The system was unveiled in Berlin at the German Federal Institute for Materials Research and Testing, known as BAM, which has been testing the materials since 2008 and has pronounced the system safe.

Also attending was a representative of Italian-based Generali Insurance, which has invested US$10 million ($14 million) in the project.

David Hart, director of E4tech, a business and energy consultancy in London, said the glass capillaries appear to be an "interesting" technology that would be "very significant" if it were to provide the energy claimed by the company. But if it means creating a new refuelling infrastructure, "it may still not be the right answer for cars," he said.

Like electric cars, the driving force behind hydrogen research is the need to break away from oil and rein in emissions of greenhouse gases blamed for climate change, especially carbon dioxide from industry and transport. Transportation adds about 13 per cent of man-made carbon to the atmosphere.

Hydrogen boasts zero emissions. It can be produced from water through electrolysis, or harvested as the waste product of nuclear reactors and chemical plants.

"In terms of saving carbon dioxide, you do a great deal more with renewable hydrogen," said Danny Dicks, a biofuels expert from the British consultancy group Innovation Observatory. "So ultimately, hydrogen is where things ought to be driving toward."

Automakers, for now, still are focused on battery power. At the Geneva Motor Show last month, nearly all major manufacturers displayed their latest electric vehicles or plans to produce them. The few hydrogen vehicles on the floor attracted little attention.

It was not always that way. US President George W. Bush allocated US$1.2 billion for hydrogen research and said in his 2003 State of the Union address: "The first car driven by a child born today could be powered by hydrogen and pollution free."

The Obama administration largely scrapped the program.

In Europe, too, hydrogen is low-priority. The Dutch government, for example, recently announced a €5 million ($9.4 million) subsidy for hydrogen, but gave eight times more for electric cars. Buyers of plug-ins get tax breaks and rebates, and cities like London and Amsterdam are planting charge-up pillars on their streets.

"Electricity is taking all the subsidy schemes. It's taking it away from hydrogen," said Robert van den Hoed of Ecofys, an independent Dutch consultancy on renewable energy.

The main reason is cost. Electric cars are road-ready and in production, while hydrogen vehicles are still experimental. Nissan's new electric car, the Leaf, will go on sale for about US$25,000 in the United States, including a Government rebate.

- Additional reporting, Agencies