It is not often that technology gets a mention in the state of the Union address by a US president. So President George W Bush picking out hydrogen fuel cells for special mention in the address in February with the promise of $1.7bn for development projects was notable. Nick Flaherty reports.

Fuel cells offer higher energy densities than existing battery technologies by using hydrogen, in the form of methanol or impregnated in a polymer, and oxygen, with end products of water and electricity. A 'reformer' can be used to create the hydrogen from another source, which can even be oil or petrol.
But a lot of the fuel cell technology is being developed for the military, space and avionics applications, and this is based around the proton exchange membrane (PEM) technology. Many of these applications are to replace existing primary battery systems or generators to drive PCs and other electronic systems installed in vehicles and aircraft.
A UK start-up, Intelligent Energy in Loughborough, is working with Boeing to develop the world's first fuel cell-powered manned aircraft to be demonstrated before the end of the year.
The Fuel Cell Airplane Demonstrator Project will prove that fuel cell technology can provide environmental benefits and optimise fuel usage for commercial aircraft. Boeing believes that fuel cells have great potential to replace auxiliary power units for commercial passenger and freight air fleets.
"Fuel cells show considerable potential for power delivery in many applications, none more graphically demonstrate this potential than manned flight," said Dr Harry Bradbury, CEO of Intelligent Energy.
The US Army Tank-automotive and Armaments Command (TACOM) has developed a truck fitted with a methanol-based fuel cell as an auxiliary power unit (APU). The 5kW APU, which includes a fuel cell stack manufactured by Ballard Power Systems, provides the electricity for the computers, satellite dishes and three-dimensional mapping systems.
At the same time GM has announced a diesel hybrid military pickup truck also equipped with a fuel cell auxiliary power unit (APU).
"Our prototype truck incorporates advanced diesel hybrid powertrain technology and introduces the military to the flexibility and security of fuel cell electric power," said Larry Burns, GM's vice president of research and development and planning. "This defense project is a great opportunity to put large numbers of diesel hybrids and stationary fuel cell units in operation in the interest of national security. We also anticipate that it will accelerate cost-effective and durable civilian applications of hybrid-electric vehicles and fuel cells. As an early customer, the military will help drive down costs and spur the eventual development of a hydrogen-based economy."
The APU, designed and built by Hydrogenics, is a 5KW proton exchange membrane (PEM) regenerative system. When the vehicle is driven, the PEM electrolyzer uses the diesel engine to provide the electricity to break down water into hydrogen and oxygen, with the hydrogen stored for future use. Later, with the engine off, the stored hydrogen, together with oxygen from the air, is fed to the fuel cell to produce electricity, returning the pure water as a byproduct, which is stored to repeat the cycle.
This means the cell produces its own hydrogen and the Army does not need to add a hydrogen to its logistics. Any additional water is not a problem since water is already provided to the troops and, in a difficult situation, the fuel cell-produced water is drinkable.
"The fuel cell unit delivers the same amount of power as a conventional generator without broadcasting your presence," said Burns at GM. "The energy density of hydrogen and the efficiency of the fuel cell gives the same capability of equal-sized batteries but with six to 10 times longer operation, particularly in adverse temperature conditions. The military recognises these advantages as being key to its mission-critical operations."
But the focus on transportation can hide the development of fuel cells in the more traditional battery area of portable equipment.
Using different technology but a similar approach, most of the leading Japanese consumer equipment makers have been developing fuel cells to power notebook computers. Casio has been developing the technology.
In March, Toshiba showed the world's first prototype of a small form factor direct methanol fuel cell (DMFC) for portable PCs that it believes can be ready for the market next year. This has an average output of 12W and maximum output of 20W, and can achieve approximately five hours of operation with a single cartridge of fuel.
Toshiba sees an advantage in providing instant, rather than rechargable, power as well as a business in providing the replaceable methanol cartridges. It could also be used for stand-by power, as Toshiba has used the same electrodes as found in lithium-ion batteries, allowing it to connect directly to a PC or other portable device in the same way as an lithium-ion battery.

Part of the problem with the methanol-based fuel cells is the concentration at 3 to 6 per cent requires too much water to make a small battery. Toshiba has developed an approach that allows a higher concentration of methanol to be diluted by the water produced as a by-product of the power generation process. This means the methanol can be stored at a much higher concentration, and achieves a fuel tank ten times smaller than existing systems. The current prototype can operate for approximately five hours on 50cc of high concentration methanol.
Alongside this, Toshiba has developed the support devices needed to give efficient control of power supply: sensors to monitor methanol concentration and liquid level and a 'remaining quantity' sensor to tell users when they need to change the methanol fuel cartridge.
The momentum is building with the methanol-based technology. US startup Polyfuel, partly funded by chip giant Intel, also demonstrated a working prototype of a DMFC cell in March. "The demand for 'always-on' power is growing exponentially as the mass market adoption of portable devices and laptops increases," said Jim Balcom, President and Chief Executive Officer of PolyFuel. "Direct methanol fuel cell technology is the answer to the portable power crisis we, as an industry, are currently facing. Soon, users will to be able to operate their notebooks indefinitely, without plugging in, by simply hot-swapping a fuel cartridge. The benefits of fuel cell technology to the consumer are enormous," he said.
In the US, Neah Power Systems is also developing a compact methanol-based fuel cell to power mobile electronics products, such as notebook PCs and advanced communications gear. This is based on a patent-pending silicon-based architecture, rather than carbon, that the company claims will allow portable computers to run all day on a single charge.
It uses a porous silicon substrate that allows for high levels of electro-chemical activity and electricity generation, which is expected to result in higher levels of efficiency and much higher power densities when compared with traditional PEM-based designs and so will fit inside, rather than outside, the computer.
The company is planning to demonstrate the notebook-PC battery cell by the end of the year, negotiating with computer makers in 2004 and shipping in 2005.

Meanwhile SFC Smart Fuel in Germany has been pioneering fuel cells in portable applications in Europe. It has been jointly developing a fuel cell for notebook PCs with computer maker Medion, and demonstrated its 'Energy Docking Station' back in March. This uses a single, exchangeable fuel cartridge containing methanol and when the cartridge is empty, it can be 'hot-swapped' and exchanged without interrupting the operation of the computer, and can also be used to charge other devices, such as a mobile phone.
SFC is planning to market the Energy Docking Station from next year.
And other areas of fuel cell development are being driven by new technologies such as carbon nanotubes. Being able to build structures at the atomic level, such as the carbon 'nanohorns' used by NEC's fundamental research labs for a prototype fuel cell for a mobile phone giving ten times the energy density of lithium ion.
The developments are continuing, and George W Bush's speech may well become the watershed that marks fuel cell technology becoming a mainstream technology.
But it is in the portable market, where hundreds of millions of cells could be used that is the real opportunity for economies of scale that could make fuel cells a truly ubiquitous technology. The distinct silence on that area is far more worrying.