Consumers will still have to wait a few years before they can swap the batteries of their cell phones for more environment-friendly fuel cells, the world's top handset maker Nokia said on Tuesday.

It is not a technology question, it is more like a supply-chain issue at the moment, Tapani Ryhanen, head of strategic research at Nokia Research Center, said at a seminar celebrating the center's 20th anniversary.

Ryhanen said the technology itself was already available and Nokia had tested it.

A few years you would still need to wait, he said, adding that the industry had to sort out how to supply the fuel to consumers.

Fuell cells use a catalyst like platinum to start a electrochemical process to generates electricity from making oxygen react with a fuel such as hydrogen, ethanol or methanol.

Energy