Toshiba has figured out how to power a portable computer using fuel cell technology without the need for a power unit larger than the PC itself.

Toshiba’s small form factor direct methanol fuel cell (aka DMFC) can operate for five hours, generating between 12W and 20W of power and is electrically compatible with existing Lithium-Ion rechargeable batteries. It’s not yet the size of a typical notebook battery, but Tosh is working on it.

The fuel cell generates electricity as a by-product of a chemical reaction involving dilute methanol. Methanol can be produced easily and in vast quantities, so the fuel cell is widely seen as a very inexpensive alternative to batteries. And by generating electricity directly, it’s arguably a greener technology too.