Wireless ZigBee Smart Energy Keys Transition

While many have seen the AC power grid as the most ubiquitous data network of all, power-line networking has yet to broadly succeed. Now, the electricity distribution segment is looking to add intelligence in meters and energy-consumers such as home appliances, and they need a ubiquitous communications scheme to enable a smart grid. It appears that the ZigBee Smart Energy standard will be the answer and that a wireless channel will be a key, although the new Smart Energy protocols may ultimately run atop multiple network types.

Figure 1: The GE GeoSpring Hybrid Water Heater, the first ZigBee Energy-certified appliance, offers energy-saving heat-pump technology as well.

ZigBee began as a low-power standard for wireless personal-area networks. It is based on the IEEE 802.15.4 standard and promulgated by the ZigBee Alliance (www.ZigBee.org). The mesh-networking-capable technology targets home automation and industrial networks.

The ZigBee Alliance has essentially completed the ZigBee Smart Energy Version 2.0 specification. The Version 2.0 spec is at the 0.9 draft level, and the ZigBee Alliance is no longer accepting public comments. ZigBee Smart Energy is poised to be the de facto standard for home-area networks (HANs). The standard is based on the Internet Protocol (IP), and the ZigBee Alliance has developed the standard with input from other organizations, including NIST (National Institute of Standards and Technology), the HomePlug Powerline Alliance, the Wi-Fi Alliance, and others.

The HAN concept has a long history. For almost two decades, technologies such as the CEbus (Consumer Electronics bus), Echelon’s LonWorks technology, and others have sought to enable HANs. The target has been luxury-oriented features such as lighting controls in homes. Now, it appears energy efficiency gains enabled by smart appliances will finally lead to widely deployed HAN technology.

ZigBee Smart Energy will enable advanced metering infrastructure (AMI) technology and demand-response programs in homes. Utilities will be able to remotely read and communicate with smart meters that are now being deployed in a number of utilities. In turn, the meters will use ZigBee wireless technology to communicate with smart appliances in the home and with other compatible products such as display panels that allow consumers to monitor and control their energy usage.

A smart meter, a HAN, and smart appliances can work together to enable the utility and homeowner to save energy and money. Utilities can send time-of-use pricing data to homes so that high-energy-usage applications such as washing clothes can be limited to off-peak times when rates are low and when the energy usage would least impact the utility. The technology could ultimately let the utility control the HVAC thermostat of willing consumers.

The Smart Grid technology will presumably reduce the demand on the grid. It can both reduce carbon emissions and perhaps eliminate the need for some new power plants. Moreover, consumers and communities can save money and live in a greener environment.

While other attempts at establishing HAN technology has lacked a killer application, ZigBee Smart Energy has energy and a willing base of utilities that are eager to help. For example, Southern California Edison announced in July that it has installed its one-millionth Itron OpenWay smart meter. The Itron OpenWay meter enables AMI applications and is a ZigBee Smart Energy certified product.

Now, it appears that appliance makers will also adopt the ZigBee Smart Energy technology with General Electric (GE) leading the way. The company just announced the first consumer appliance – the GeoSpring Hybrid Water Heater – that is ZigBee Smart Energy certified. The water heater is based on heat-pump technology to maximize energy savings. Moreover, GE said that it will launch more ZigBee Smart Energy appliances in the fall, including refrigerators, washing machines, clothes dryers, dishwashers, ranges, and microwaves.

The ZigBee Alliance has a long list of Smart Energy-certified products on its website. It is important to note that ZigBee Smart Energy is a profile that lives on top of the network layer. In other words, ZigBee Smart Energy communications can traverse many types of networks, although ZigBee wireless networks first developed the protocol.

The ZigBee Alliance and the Wi-Fi Alliance announced back in March that the two would collaborate on HAN applications. Additionally, as previously noted, the HomePlug group has been involved with the standard development. Thus, expect the ZigBee Smart Energy protocol to flow both on Wi-Fi and power-line networks.

The embedded design team that wants to jumpstart a ZigBee Smart Energy project has a number of places to get help, including the vast number of ZigBee development kits available from DigiKey. Ember, for example, offers a complete Smart Energy Suite, including embedded software, tools, and ICs that are combined in development kits. Moreover, Ember Senior Vice President Skip Ashton has jointed the NIST Smart Grid Architecture Committee, which is in charge with shaping U.S. smart grid standards.