Not long ago, many experts ruled out the pursuit of energy scavenging as a power source, saying that advances in battery technology and power optimization would render it unnecessary. But recent developments suggest that it might be premature to relegate power harvesting to a few special applications.
Hasty Conclusions
Today, interest in power harvesting is picking up again. Many view power as the Achilles heel of wireless devices. Batteries are perceived as inadequate for long-term operation, and changing batteries in many applications is just as costly as a total failure of the device. But these views have not always had the support that they do today.
During a conversation a few years back, I learned that the Palo Alto Research Center (PARC) had discontinued all research on power harvesting. Researchers there noted that batteries were getting progressively smaller and more powerful and electronics (including industrial wireless devices) were getting less power hungry. When they projected these two empirical curves, they concluded that the market for power harvesting would remain too small to justify their attention.
But recent events in the industrial space lead me to believe that their conclusions may have been hasty. Companies are beginning to develop market-ready products that get all the power they need from the environment. And industrial environments are ripe with power, so they look promising.
While early wireless sensors used photovoltaics to charge internal batteries, in today's environment, solar cells are old news. Recent technology is much more interesting. For example, Enocean markets a light switch that uses the energy of the toggle itself to broadcast the on/off signal to the fixture. RLW in Pennsylvania is building devices that use "advanced energy harvesting" for condition monitoring on Navy ships. And if you attended the DOE program review on June 5 at Sensors Expo, you heard Jeremy Frank from KCF Technologies talk about low-cost vibration power harvesting for industrial wireless sensors. And if you read the May issue of Sensors Wireless & M2M newsletter you saw the debate on power harvesting in that issue's Wireless Forum feature.
Could something be in the wind? We'll keep our eyes open.