Charger power savings

The world's top five cellphone makers yesterday launched a common energy rating system for chargers, making it easier for consumers to compare and choose the ones consuming the least energy, Nokia said.

The new rating system is a cellphone industry response to heavy criticism from environmentalists. The industry has become the world's top consumer electronics business by volume.

The new ratings system covers all chargers currently sold by Nokia, Samsung, Sony Ericsson, Motorola and LG Electronics, and ranges from five stars for the most efficient chargers down to zero stars for the ones consuming the most energy.

If left plugged into the socket, chargers continue to use electricity even if the phone is disconnected. Nokia said around two-thirds of the electricity used by mobile phones is wasted this way.

"If the more than three billion people owning mobile devices today switched to a four- or five-star charger, this could save the same amount of energy each year as produced by two medium-sized power plants," Nokia said in a statement.

The world's top four charger makers include Flextronics, China's BYD Co., Emerson Group and Finnish Salcomp.