For the cellphones and laptops of the future, the batteries may run on alcohol or hydrogen -- and if they run out of juice, you simply refill them.

Japanese electronics maker Toshiba launched two MP3 players in October that run on DMFC fuel cells, using methanol as fuel. The larger of the two devices has a hard drive and an edge length of more than 12cm. The fuel cell has a 10ml tank offering an active life of up to 60 hours, Toshiba reports.

The smaller device is no larger than a pack of gum, offers Flash storage and holds 3,5ml of fuel -- good for 35 hours of musical enjoyment.

Canon has announced plans to operate its printers, cameras, cellphones and MP3 player using so-called PEM fuel cells. A prototype was presented in early November in Tokyo. Unlike many of their competitors, Canon's developers have cast their lot with hydrogen energy sources.

Energy generation using fuel cells is based on the detonating gas reaction between water and oxygen. The two elements react explosively when brought together, with one part oxygen and two parts hydrogen producing one water molecule. A fuel cell is used to harness this reaction in a controlled, explosion free manner. The energy that is freed up in the process can be used as electricity.

The current crop of fuel cells tends to deviate from the textbook example, not least because of safety concerns. According to the Initiative Brennstoffzelle (IBZ) in Essen, two technologies have been developed for micro applications.

Polymer-membrane fuel cells are created with gaseous hydrogen, while direct methanol fuel cells covert methanol directly into fuel within the cell. A third system comes in the form of PEM fuel cells that are tanked with methanol to be converted into hydrogen and carbon dioxide in a so-called reformer.

According to the IBZ, fuel-cell phones and cameras have been announced by many other electronics firms in the past, including Sony, NEC, NTT DoCoMo and Hitachi. No market-ready devices ever emerged, however.

Because fuel-cell devices will initially be much more expensive than competing models with traditional technology, it is not enough just to replace the battery with a fuel cell, says engineer Robert Hahn from the Fraunhofer Institute for Reliability and Micro-Integration in Berlin. The institute has developed mini fuel cells that are only several cubic centimetres large yet offer a higher energy density than batteries.

If manufacturers hope to woo consumers to the new technology, then the fuel cells will need to offer significantly longer power lives than the current standard for rechargeable batteries, lithium ion. Practically speaking, the experts estimate that the fuel cell must offer three times the power for a unit with the same dimensions. And that may well be the amount of power that the next crop of power-hungry applications -- like television over cellphones -- will require. -- Sapa-DPA