Now that telecom networks have a bigger footprint than electric power networks, the question of power sources is assuming increasing importance. Quite a lot of work is being done in our region on reducing the power requirements of base stations and of substituting for expensive diesel generators. In Pakistan, using renewable sources at base stations are mandatory for those obtaining subsidies. The power is also made available for the recharging of handsets.
But would it not be wonderful if handsets require no external power and no batteries? That day may not be too far in the future according to NYT:
Two types of research groups are extending the boundaries of low-power wireless devices, said Brian Otis, an assistant professor of electrical engineering at the University of Washington. Some researchers are working to reduce the power required by the devices; others are learning how to harvest power from the environment. “One day,” Professor Otis said, “those two camps will meet, and then we will have devices that can run indefinitely.”
Professor Otis, who designs and deploys integrated circuits for wireless sensing, is in the first group. Dr. Smith of Intel is one of the harvesters, gathering radio power that is now going to waste. And there are plenty of radio waves in the air to provide fodder for him as they spread from Wi-Fi transmitters, cellphone antennas, TV towers and radio stations.
Some of the waves travel to living-room televisions, for example. But others, which would otherwise be wasted as they rise through the atmosphere into space or are absorbed in the ground, can be exploited, he said. “Ambient radio waves,” he said, “can already provide enough energy to substitute for AAA batteries in some calculators, temperature and humidity sensors, and clocks.”