It's something of a watershed time for cell phones powered by fuel cells.

At the Mobile World Congress in Barcelona this week, Toshiba unveiled a mobile handset about the size of a contemporary chunky PDA smartphone, approximately the size and weight of the HTC Mogul.

It's about 160 grams, roughly twice the going weight for a cellphone, about an inch thick and powered by a lithium ion battery which was kept charged by a direct methanol fuel cell (DMFC).

It's not nearly as heavy as previous prototypes, and Toshiba expects it will get even smaller by the time the company's first fuel cell devices are released in Japan later this year, according to an executive.

"We cannot comment on timeline details, but by the time the DMFC device is commercialized, we expect to meet form factor and weight of comparable battery-powered phones," said Sean Collins, VP Advanced Technology Group for Toshiba America Electronics Components to Cleantech.com.

The company didn't reveal the amount of fuel it can store. But it claimed the fuel-cell "hybrid" handset would operate about twice as long as normal mobile phones.

How big is the new prototype? A photo »

Fellow Japanese company NEC is rumored to be working on an ethanol fuel-cell powered cellphone of its own, dubbed the Flask.

Images of a clear plastic phone with colored liquid sloshing around inside have started circulating online in recent weeks.

NEC claims the phone will be released later this year, but has provided no other information.

A photo of the gorgeous BiC lighter-style NEC prototypes »

And at the Consumer Electronic Show in Las Vegas last month, Vancouver-based Angstrom Power announced it had fitted its Micro Hydrogen fuel cell into one of Motorola’s MOTOSLVR phone, without modifying the phone’s exterior.

Angstrom spokesman Aron Levitz declined to provide exact specifications to Cleantech.com, but maintained the phones were safe.

The fuel cell did give off heat as a byproduct, like all fuel cells, but not enough to make holding the phone uncomfortable, he said.

"The fuel cells we use have very high efficiency," he said. "Tossed into a fire, they wouldn’t be likely to explode like a lighter exposed to flame." [ed.: let's let him do the testing, thanks.]

He also noted that Angstrom's systems had passed safety regulations, and that Angstrom had a special permit allowing cellphones powered with its hydrogen cells to be carried aboard aircraft in Canadian airspace.

Recharging the cellphone won’t be too different from what is being done now, said Levitz. The charging station is to look like a desktop phone cradle.

Angstrom expects to have its first commercial models out in 2010.

Other companies pursuing similar technology include MTI Micro (see Honey, MTI shrunk the fuel cell), which has developed a fuel cell chip that can be mass produced for cell phones and other applications, and New York-based Medis Technologies (NASDAQ: MDTL).

What kinds of risks are consumers facing with fuel cells so close to their faces?

Ron Enderle, principal analyst at the Palo Alto, Calif.-based Enderle Group thinks ethanol is emerging as a fuel of choice for fuel cell-based cell phones.

"Currently there are concerns with regard to the potentially poisonous output of methanol, which has me favoring ethanol for the needed regulatory approval."

"Methanol could likely make it through the approval process. It would just be harder. But given that concerns with regard to issues like this are increasing, I'd give ethanol the edge."

Enderle said he'd put money on hydrogen as the eventual fuel of the future.

"Hydrogen, if we take cost out, is likely the safest but it has a rather high cost disadvantage right now due to production and storage issues. This could change though. There is a lot of money pointed at fixing this. The output is water, and you don't get much safer than that."

With reporting by Massie Santos Ballon.