"For all the advantages that hydrogen gas offers, you have to store it at high pressure, or store it very cool...which is fine [in a car] when you can have a giant reinforced tank in the back," says Dan Benjamin, senior analyst for ABI Research of Oyster Bay, N.Y. "It wouldn't be that viable for a small device. Methanol is not as good as hydrogen, but it's been much easier to work with."

Cost is still an issue for Millennium's fuel cell system. So, as the company tweaks its process to drive down the expense for future consumer use, it is also developing applications for the military, where there's a greater immediate need for the technology -- and deeper pockets to pay for it. Millennium has partnered with Massachusetts-based fuel-cell maker Protonex Technology to develop fuel cells for U.S. Air Force personnel to use as a power source for running communications devices on field missions.

It may be late 2007 or early 2008 before fuel cells using Millennium's system hit the consumer market, says Giolli. Indeed, most fuel-cell advocates believe it will be a few years before users are powering up their notebooks and cellphones with these battery replacements, but the market potential is apparent. ABI Research predicts that by 2012, portable fuel cells (or micro fuel cells, as they're also known) will power nearly 15 percent of the world's laptops.

Meanwhile, a few companies hoping to be early to market, including Toshiba and New York City-based fuel-cell startup Medis Technologies, have announced plans to release their first models this year.

Regardless of their approach, Benjamin says almost all of the major portable fuel-cell developers “are still wrangling with issues of size, price, concentration [of the fuel], and the functional life of the fuel cell."

In spite of the forward movement he sees in the market, Benjamin advises mobile users not to plan on picking up a fuel cell for their laptop this Christmas holiday season. 

"It's not exactly been a secret that [the release of micro fuel cells] keeps getting pushed back," Benjamin says. “We keep hearing these 'we hope to announce' announcements, but we should look at this in 12 months and see if anyone's released a product."