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  • New mobile phone runs on solar power

A solar-powered mobile phone aimed at consumers without access to electricity goes into production next month (April).

The first phones to be manufactured will be sold in Papua New Guinea, Tonga and Vanuatu in June. Digicel Group, the mobile phone company that will distribute and provide network coverage for the phone, predicts a market of 700,000 customers across Central America, the Caribbean and the South Pacific.

People without access to electricity often pay brokers to charge their phones, according to Tom Bryant, director of procurement and distribution for Digicel Group. "It's a lifestyle necessity for many," he says. "But many of these brokers are expensive and you don't get a full charge either."

The new handset must be left in full sunlight for an hour to power a 15-minute conversation and is fully charged in around eight hours.

There is so much interest in solar-power, particularly in Africa, says ZTE — the Chinese manufacturer building the handset — that it plans to create a range of solar-powered phones. Korean manufacturers Samsung and LG have also unveiled prototype solar phones in the last month.

Creating a small, cheap solar powered phone that can charge in a reasonable amount of time is an engineering challenge, say manufacturers. 

Solar cells for small devices emit 0.5 volts of electricity, but a mobile phone's lithium-ion battery needs 3.7 volts to charge. Older solar phones, therefore, required several cells.

But the new phone needs only a single cell, which is combined with electronics that boost the voltage available to the battery, which is also modified to withstand temperatures of up to 45 degrees Celsius so the handset can be left out in the sun.

But many of the 1.7bn people worldwide without access to electricity might not be able to afford this handset's US$40 price tag. ZTE's cheapest non-solar phone costs US$25.

Paul Norrish of G24I — a company that has won World Bank awards for solar panels that can power several phones, and even lights, at a time — is sceptical, saying handsets are so valuable that people are unlikely to leave them in the sun to charge.

"People do not let their phones out of their sight. It's an interesting gimmick. I don't believe it is viable."