Nippon Telegraph and Telephone Corp. (NTT) will launch the unit, Pocket Energy, in Japan in May for a little under 20,000 yen (190 dollars) per unit.

"This will enable you to recharge your devices during trips abroad or in the wake of disasters," Keiichi Yasuda, chief producer at NTT's energy and environment team, told reporters.

The unit comprises a solar panel that can be folded in two, an electricity-storing tablet and connecting cables. The system weighs about 300 grammes (10 ounces).

If put in direct sunshine for four hours, it can store enough electricity to run a mobile phone for four consecutive hours of talking.

"We expect to sell several thousand units in the first year but aim to score (annual) sales of one billion yen in three years," said Kenji Kogure, environmental business chief at NTT Advanced Technology Corp.

NTT targets municipal governments and corporations as the main customers, he said.

Pocket Energy can be used for most mobile products including compact-disc players, game consoles, cameras and cellphones but not for notebook computers.

NTT plans to export it in the near future, Kogure said.

SPACE.WIRE