A 50-Watt Cellular Network  

Technology Review has an article on solar power mobile phone networks for remote areas - A 50-Watt Cellular Network.

An Indian telecom company is deploying simple cell phone base stations that need as little as 50 watts of solar-provided power. It will soon announce plans to sell the equipment in Africa, expanding cell phone access to new ranks of rural villagers who live far from electricity supplies.

Over the past year, VNL, based in Haryana, India, has reengineered traditional cellular base stations to create one that only requires between 50 and 120 watts of power, supplied by a solar-charged battery. The components can be assembled and booted up by two people and mounted on a rooftop in six hours.

One such station--dubbed a "village station"--can handle hundreds of users. Groups of such village stations feed signals to a required larger VNL base station within five kilometers. In turn that larger station, which is also solar-powered, relays signals to the main network. The village station can turn a profit even if customers spend on average only $2 a month on the service, instead of the $6 required to make traditional systems cost-effective, the company says.

"We've scaled down the cost, the energy, and the equipment so that almost anybody can deploy it," says Rajiv Mehrotra, VNL's CEO. "It lends itself to many business models that can serve the bottom of the pyramid," a reference to the roughly 1.5 billion rural people who do not have access to electricity grids around the world.