An industry standards group that includes chip makers Intel and STMicroelectronics has published a document detailing the requirements a fuel-cell technology would need to power a mobile PC, the group said in a Thursday statement.

Apple will begin using Intel processors in its Mac computers from 2006. Intel-based laptops are expected to be in the first releases.

The new guidelines from the Mobile PC Extended Battery Life Working Group should help speed the development of longer lasting fuel-cell power sources for notebooks and other mobile computers, a development viewed as important for the growing popularity of WiFi and other wireless Internet technologies.

The development of wireless power supplies has lagged mobile Internet efforts. Batteries still last only a few hours in notebook computers before needing a recharge, while fuel cell systems could last for days, the group says.

"[The initiative] is important for Centrino," said Connie Brown, an Intel spokeswoman.

Wireless Web

Intel's popular chip package has fueled a surge in notebook computer sales in recent years and popularized the use of the wireless Web in coffee shops, airports, and other places outside the office and home.

The guidelines will help developers of fuel cells for mobile devices, like Millennium Cell and Tekion Solutions, by outlining key technical requirements for fuel cells to work well inside a mobile PC.

Fuel cells operate differently than batteries. One of the troublesome aspects of using fuel cells in mobile PCs is they provide a steady supply of power, whereas power demand in notebook computers is very uneven, driven by bursts of power demand as different parts of the notebook, like the DVD drive or hard drive, are tapped for use, the group said. The stored charge of a battery matches this kind of uneven power demand, but fuel cells need careful management.

Batteries also require fewer supporting components inside a mobile PC, the group said. A fuel-cell system includes the fuel cell itself, as well as supporting systems similar to a car engine, like a fuel pump, cooling system, and a starter battery.

The guidelines cover these issues as well as electrical, mechanical, control, thermal, environmental and regulatory aspects of fuel cell designs for mobile PCs, including those made for use inside a device, and external fuel cells.