ZigBee Wireless Adopts Energy Harvesting

The low-power wireless energy “Internet of Things” standard ZigBee, used in smart metering systems, is now available in a battery-free version which harvests energy.

The new specification will allow ZigBee, which is specified within the UK government’s ambitious smart meter programme, to operate without batteries by harvesting energy such as ambient radio waves. However, the standard still faces significant competition from other low-energy solutions such as Bluetooth Smart, the low energy version of the Bluetooth personal area network (PAN) standard.

ZigBee stardust?

Low energy wireless has been a competitive – but very slow moving – field, andZigBee’s death has been hailed many times, especially since Bluetooth announced a low energy version (currently called Bluetooth Smart, but previously known under other names including WiBree) which is expected to have bigger scale and lower power demands.

ZigBee has been going for more than ten years, with a particular emphasis on using mesh networks to pass data between low-cost radios, intended as a simpler substitute for Wi-Fi or Bluetooth in sensor applications often referred to as the “Internet of Things”.

Bluetooth Smart actually uses less energy, according to Nick Hunn, CTO of smart metering data analysis firm Onzo: “Energy efficiency in radio is about how well you can stay asleep, and Bluetooth Smart is a more recent specification,” he said. ZigBee’s mesh architecture is an overhead, he added.

In fact, competition between low-energy radio systems is now all about the upper layers of the protocol, and the size of the developer community, since silicon designers use the same chips for all the different standards, only adding different software.

The amount of energy overhead in a mesh network, or the expense of providing a coin-sized battery for the wireless, is unlikely to make as much difference as market scale – and low-energy Bluetooth is delivered in more devices he said.

“ZigBee has done a good job of becoming the accepted standard across the smart metering industry,” said Hunn. “But there aren’t many meters going out, at the moment, and most of them are fairly closed systems.”

The UK government has promised a nationwide rollout of smart meters, due to start in 2013, and complete by 2019, but this is currently on hold while the specification for those meters is agreed.

“The Green Power feature for ZigBee PRO will allow development of the most eco-friendly products possible,” said Bob Heile, chairman of the ZigBee Alliance

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