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Harvesting energy from thin air

Vincent Ting | Moment Open | Getty Images

The way we power and charge electronic devices is changing, and fast. Today, mains charging, wireless charging and even solar charging are some of the options at our disposal.

Now, one British company has developed technology that it says will "provide continuous power" to low energy internet of things devices, which could mean that power cables and battery replacements eventually become redundant.


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Drayson Technologies' patent pending Freevolt has been designed to harvest radio frequency (RF) energy from broadcast and wireless networks. These networks include WiFi, digital TV, 2G, 3G and 4G. The technology was developed by both Drayson Technologies and researchers at Imperial College London.

"The idea behind Freevolt is to use the wasted energy from existing wireless transmissions – so from cellular networks or from WiFi – (and) to harness that using a new type of harvesting antenna device to power small sensors and beacons in a way which hasn't been possible before," Paul Drayson, Chairman and CEO of Drayson Technologies, told CNBC in a phone interview.

Drayson explained that a broadcast transmission was like dropping a pebble into a pond and seeing ripples expand. "The energy within the wave… is transmitted everywhere, but only a proportion of it is actually received by a receiving device," he said.

Drayson described the amounts of this kind of energy as tiny, something like tens of nanowatts per square centimeter. "We've developed a very efficient antenna which is able to harvest from more than one waveband at the same time," he said. "We're able to harvest from the WiFi frequency as well as the cellular frequency," he added.

The environmental potential of using radio frequency energy to charge or power devices is considerable. "We're basically recycling energy which is at present going to waste, so that's a good thing environmentally," Drayson said.

"Secondly, it will mean fewer batteries," he added. "That's what we see as the main environmental benefit from this, is that batteries will last longer or will not need to be replaced and that's a real win in terms of the disposability of those devices, those batteries."

According to the Natural Resources Defense Council (NRDC), the impact of batteries – as well as devices such as cell phones and computers – is significant. These kinds of items contain harmful, toxic heavy metals such as mercury and lead.

According to the NRDC, when thrown away these objects can end up in landfill sites and their toxic compounds, "can leach into soil and water, polluting lakes and streams."

Applications of the Freevolt technology include powering low energy internet of things devices, beacons in supermarkets and shops, and wearable tech. Freevolt has been used in the CleanSpace Tag, which is described as "a personal air quality pollution sensor."