The Dawning of the Hybrid HAN

July 9, 2010

A key tenet of the Smart Grid has always been the Smart Meter.  The meter is “smart” because it can not only report back usage information to the utility but also to homeowners – presumably to displays, thermostats and various other smart communication devices.  Over the last few years a very useful networking and application standard has emerged to help guide the Home Area Network (HAN) that is formed by these devices in connection with the smart meter.  That standard is called the ZigBee Smart Energy Profile.

The 1.0 version of the Smart Energy Profile envisioned having one communication channel in and out of the HAN – either via the utility meter network with the meter being the gateway or via the consumer’s Internet connection with an IP to ZigBee gateway.  However, as HAN use cases have grown up, it has become evident that HANs should allow for multiple “doors” – that is, meter network or Internet. We call this a “Hybrid HAN.”

From the utility side, this is important for several reasons. Once devices start joining meters in homes, these devices naturally must be maintained with regular firmware upgrades. For now utilities have enough on their plate without taking on large-scale in-home device management and upgrades. This means the consumer’s broadband networks must be leveraged.  However, utilities still need to ensure that the price and Demand Response messages arrive reliably and securely to the home via the meter network.  The “two doors” of the Hybrid HAN make this possible.

From the consumer side, as energy displays and control devices arrive into consumers’ homes, consumers will naturally expect to have useful and convenient features for those devices, such as weather updates or news and sports scores on their displays, or remote control of their thermostats and smart appliances via the Web or smart phone. The consumer’s broadband network is the perfect way to deliver these features while still utilizing the utility meter network for pricing, DR and consumption reporting.