New way to harvest renewable energy from mobile towers

Scientists have found a way to harvest renewable or ambient energy from mobile phone base stations or communication towers to power battery-operated wireless sensors used in many industries including health and agriculture.
Lead researcher Salman Durrani from The Australian National University (ANU) said current wireless sensors for buildings, biomedical applications or wildlife monitoring use batteries which are often difficult to replace.
In a first, researchers have accurately modelled how much energy it takes to sense and transfer information by wireless sensors.
"A major problem hindering the widespread deployment of wireless sensor networks is the need to periodically replace batteries," said Durrani.

Wireless sensors are increasingly being used in many aspects of daily life. For example, sensors are used to measure temperature, wind speed, light, humidity and soil moisture to optimise the growth of grapes and prevent crop loss due to excessive heat or frost.
Wireless sensors are used in various sports, such as rowing, to collect performance data from athletes. They are also used for condition monitoring of structures such as bridges and machinery in factories.

The research found it was feasible to replace batteries with energy harvested from solar or ambient radio frequency sources such as communication towers or other mobile phone base stations, with communication delays typically limited to less than a few hundred milliseconds.

Durrani said although the technology was years away, the research dealt with an important practical problem.
"If we can use energy harvesting to solve the battery replacement problem for wireless sensors, we can implement long-lasting monitoring devices for health, agriculture, mining, wildlife and critical national infrastructure, which will improve the quality of life," Durrani said.