British Gas Smart Meters – Part 2

Following my mission to get smart meters installed I started to look into the possibility of using Zigbee to gather my energy usage statistics from my new state of the art meters. This, as it seems, would not be as easy as I at first thought.

British Gas ecoMeter

Tantalisingly, on the back of the ecoMeter In Home Display (IHD) supplied with my smart meters, it reads: “Zigbee Certified product (Energy)”. My first thought was that this would be as simple as getting a Smart Energy compatible Zigbee gateway or USB device, associating then with the smart meters Zigbee Home Area network (HAN) and I would then be able to read my consumption stats from my meters.

There are a few Zigbee products available like the Digi ConnectPort X2e and Nexvox Z-201 which I thought I may be able to connect to my smart meter HAN, but reading further into smart meters I found out that the utility company may have to permit new Zigbee devices connecting to the smart meters HAN. I contacted the British Gas to ask whether it would be possible, unfortunately, it would seem, this is not possible due to a number of security restrictions which have been put in place on British Gas’s ‘Phase 3’ smart meter setup. I was fortunate to be able to speak to one of the engineers in British Gas’s smart meter team and he explained some of the security restrictions to me:

  • Software developers at British Gas and Trillaint (the manufacturer of the Zigbee hub) decided to limit the number of devices (MAC addresses) permitted to associate with the hub to 3. Basically only permitting the Electricity Meter, Gas Meter and In Home Display.
  • British Gas have considered the option of adding further MAC addresses for additional Zigbee devices, but there were security concerns that hubs may accidentally (or maliciously) be linked to incorrect smart meters (i.e. the neighbours).
  • To further increase security British Gas also change the keys, used to encrypt smart meter traffic, every few months. So even if someone did managed to connect a device to their HAN it would only work up-until the point where the keys are changed.
  • The hub, smart meters and IHD are all managed remotely and if any meter tampering is detected the meters can be switched off remotely.
  • To prevent unauthorised tweaking the ecoMeter IHD also requires a PIN number in order to access the advanced settings.

20130915-164225.jpgIn absence of being able to collect stats via Zigbee, British Gas are apparently trialling a ‘Virtual IHD’, a smartphone app which will display energy usage echoing those on the ecoMeter. The data for this app however would not be gathered via the home Zigbee network but rather from the British Gas head end systems via the internet.

I am a little disappointed that I can not use Zigbee to access my energy usage from the smart meters, especially considering this is one of the larger selling points of smart meters, I hope that this will be a future phase to British Gas’s plans. One of the government document [Smart Metering Equipment Technical Specifications] states:

Defining a HAN standard in SMETS 2 and the CHTS will provide the opportunity for suppliers and consumers to link devices to the smart metering equipment in the premises. Linking devices to the HAN will be accomplished by ‘pairing’ them to the relevant communications hub. The communications hub will be required to support the linking of supplier-provided smart metering devices and of consumer access devices: these requirements will be defined in the CHTS.


Devices connected locally to the HAN to allow consumers to access their smart metering data are referred to generically as CADs [Consumer Access Devices]. CADs are expected to be available for purchase through retail stores or as part of a service: for example installing a central heating system, re-fitting a kitchen or as part of an energy supply contract.

CADs will only be permitted ‘read-only’ access to data held in smart metering equipment. For security reasons, software in the communications hub (the HAN coordinator) will prevent CADs from updating any data in smart metering equipment or from executing any functional capabilities of a smart meter.

Another government document [Smart meter data access and privacy] states:

There was also support for the use of consumer access devices connected to the Home Area Network (HAN), to enable consumers to access their consumption data in a more bespoke manner. However, consumer groups were concerned that this form of access would be used only by technology-literate consumers. Many industry and technical solutions respondents caveated their support for the HAN by stressing that issues around security and operability still needed to be finalised in the second version of SMETS to provide assurance that devices could be connected in a secure and consumer-friendly way.

So I think there is hope yet, it looks as though there is certainly thought about allowing consumers the ability to connect additional devices (CADs) to the smart meters hub, but these, at least for now, may be trumped by security restrictions (I guess rightly so).


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