By Neil Rosewell, Sentec

If an indication were required that the concept of the Home Area Network (HAN) is starting its move into mainstream consciousness then the involvement of big name technology players, like Google, Microsoft, Cisco and Intel is it. Each pushing different aspects of the end solution, these firms have all gone public with their proposed engagement with the energy industry, joining the hundreds of specialist niche players already in the field.

Of course, this is not the first time at least some of these organisations have promoted the idea of a technologically interconnected domestic utopia. But since the ‘home of the future’ first did the conference rounds in the early 2000s, a number of societal and cultural factors have caught up with them to make this most recent proposition far more engaging.

The first of these is that the widespread consumer acceptance of IT has continued to the point where many people are familiar with and have created a demand for a high level of technology-enabled, automated services. Whereas ten years ago the standard mobile phone offered SMS on a basic screen, now the iPod with its touch-screen and diverse applications is setting the standards for mobile technology. This market is far more receptive to the idea of an automated home network.

The second is that HANs now come with a clearly identified objective that a significant proportion of the market can identify with: efficient energy consumption to lower costs and mitigate environmental damage. This is no longer an exercise to satisfy the intellectual curiosity of developers and enable the addiction of early technology adopters.

The ground has thus been prepared, the idea of HANs has been planted, and conditions are right for it to germinate. And so we see a number of announcements that, taken together, are building a picture of quietly steady progress in the development and eventual deployment of HANs: standards groups and alliances have formed and are working with IT and telco giants who have positioned themselves as providers of energy management services.

Telecoms and broadband providers Bell Canada, Verizon and BT have all entered the fray, for example. Google too is extending its web dominance into the energy sector: San Diego Gas and Electric, TXU Energy, JEA Wisconsin Public Service Corps, White River Valley Electric Cooperative, Toronto Hydro and Glasgow EPB in the US, as well as Reliance in India are all testing its PowerMeter service.

We also see strategic alliances emerging between niche HAN companies and vendors of smart meters and demand response, such as the new relationship between Sensus and 4Home or Greenbox and Silverspring. In addition, the ZigBee Smart Energy protocol has recently been selected as one of the standards to be included in the US Smart Grid Interoperability Framework, and has been adopted by IEC, IETF, HomePlug Powerline Alliance and the European Smart Metering Industry Group.

But, with a few notable exceptions, these announcements are from the US. The European Union and its individual member states have been remarkably quiet on the subject of HANs. The question is: Why should this be?

NETWORK COMPLEXITY
There are a number of plausible answers to this question. First of all there are the demographics to consider. The UK’s own Suppliers Requirement for Smart Meters document of December 2008, indicates that it expects the biggest challenge to wireless local communications solutions to be found in premises of multiple occupancy, such as apartment blocks, or retirement homes, where the meter is located away from the living and working spaces being metered.

Not only does this make it difficult for the radio signals to reach the furthest dwellings, which may require the addition of repeaters or wired communications in mitigation, it also increases the chance of congestion and interference on the network.

In 2007, 46 per cent of EU27 households lived in flats, rising to 72 per cent in Latvia, 69 per cent in Estonia, 66 per cent in Spain and 62 per cent in Germany. But although the UK is seeing a growth in this type of dwelling, the majority of households – 81.3 per cent – are still to be found in detached, semi detached or terraced houses. The argument does not explain why the UK is not on a par with the US in terms of HAN development therefore.

An alternative explanation lies in the fragmented markets of Europe, which require more complex settlement systems to allow the benefits from the HAN to accrue back to the parties investing in it.

But a more likely cause is the complexity of HAN design: from the underlying architecture to the various components that make up a HAN system and the relationship between the HAN and smart meters, there is a multiplicity of options and combinations, which has created something of a market free-for-all. The HAN market therefore is in need of a clearly defined playing field: with no clear parameters or market framework that will help mitigate the risks of innovation and product development, there is unlikely to be a spontaneous rise of a market favourite.

However, a HAN market could be defined in two ways. The first is how each individual HAN relates to other elements in the utility’s wide area network. This ‘external’ definition depends on the design of the smart meter programme. The second, ‘internal’, definition comes from the way in which individual components within the HAN relate to each other and – eventually – which elements of the network the consumer chooses to have in their home, and how far they are prepared to adopt the technology available to them.

If we look first to the issues around both the external and internal pressures on HAN market development, the answers to our question about US advances over Europe start to emerge.

THE SMART METER RELATIONSHIP
There are two distinct models emerging for the relationship between the HAN and the smart meter. In the first configuration, the smart meter is the central point for collecting and disseminating information about the household’s electricity consumption.

In effect, it acts as the gateway through which external parties gain their detailed view of energy use on a minute-by-minute, hour-by-hour basis. In the second model, the smart meter is simply another peripheral device in the HAN that links the local network to the outside utilities. It may have its own secure connection for the utility’s ‘revenue grade’ data, but any other gateway functions will be performed by an independent device which, although offering certain privileges to the utilities or an AMI service company, defers control to the building’s occupants.

If a very basic smart meter, or one that uses a wired communications system, is specified then it would be necessary for the HAN to incorporate the gateway. Maintaining a separate gateway and meter in this way may prove to be a better cost solution for the utility, or it may be the most effective way of meeting particular strategic imperatives that have been formed to address any number of factors. These are the types of decisions that need to be considered when deciding on the way in which the HAN will interface with the meter, and ultimately will inform the development of HAN technology.

Therefore, if a serious market for energy applications in HANs and their components is to develop, the roadmap for the smart meter installations must be clear. The US remains the most advanced nation when it comes to smart meter deployment, with a very large installed base of AMR one-way meters, and a rapid, ongoing deployment of two-way AMI meters. While the US has a flexible approach to its programme design, leaving the details of implementation to individual utilities, it is clear that many are willing to invest in systems which will support connection to a HAN.

On the other hand, the individual countries within Europe are at very different stages along the path to smart metering. Spain is currently undergoing large-scale trials, and Sweden has nearly completed its roll-out of smart meters. However the specifications are mostly silent on the features needed for future HAN development. The UK’s own proposals currently undergoing public consultation get closer to clarity, providing some specific functional requirements for smart meters to act as HAN gateway, although it does not get as far as specifying technical solutions.

Here, the experiences of Italy provide a useful illustration of the perils of failing to provide a clear, future-proof roadmap for smart meter and energy management deployment. Italy is the most advanced country in terms of smart metering deployment on the continent and has more than 30 million installed meters. However, its smart metering system will require significant and highly disruptive modification and upgrades if it is to incorporate HANs and move on to the next stage of user-enabled energy management.

COMMUNICATION STANDARDS
The second area to explore is the relationship between the various components within the HAN. A typical HAN has three layers of functional components: the co-ordinator/gateway, the devices themselves and the communications protocols that allow the network to function. The co-ordinator is needed to maintain communication links between devices based on the protocols, but it can also be used as a gateway to a wider network – including the utility’s WAN. For some households, the co-ordinator can also be the core of a central controller, which allows the consumer to manage the network, probably through a home computer.

Secondly, the devices in the network provide information and/ or control and in the case of energy applications, these are likely to involve a degree of control over major end uses, such as a programmable communicating thermostat (PCT) or load controller for an HVAC system.

Finally, the embedded software in the devices, including the protocols that govern the management of the HAN, security software and the software necessary to translate data from HAN protocols to whatever WAN protocol is on the other side of the gateway.

For each layer or group of components there are many different solutions, applicable to different sectors of the market, and championed by many different companies from across the existing technology and consumer electronics spectrum.

The development of a HAN is dependent on the communications architecture and the networking protocols deployed, and it is essential that a high level of interoperability with a range of local devices is taken into account. That requires the local communications solution for smart metering to be based on compatible hardware, with compatible protocols and data exchange formats.

The current emphasis is on mesh technology. The availability of completely different mesh protocols, including ZigBee – currently the front runner – Z-Wave and Open RF, within each of the radio systems creates a number of significant challenges for HAN development and deployment. A device running one of these protocols will be able to communicate with all other devices running the same protocol, regardless of manufacturer or developer, but will not be able to ‘translate’ other protocols, even if they use the same mesh technology. It is also important to note that radios operating at the same frequency are not necessarily interoperable either. Several devices work in the unlicensed bands of 433, 868 MHz and 2.4GHz – including the majority of metering solutions. But these are not interoperable: Z Wave, Wavenis and M-Bus all operate at 868MHz but cannot connect to each other.

Other networked communications architectures include power line modems, and the more familiar Ethernet, Wi-Fi, Bluetooth and RS485 that have been widely deployed in more traditional, non-energy specific networks. Although none of these architectures is appropriate in their traditional format for the particular signal propagation, power consumption and network requirements of smart metering and home networks, they do demonstrate the difficulties of networking a GSM-enabled cell phone to a laptop supporting Bluetooth.

With so many protocols being considered for home area networking, there is currently no possibility of universal interoperability. In a multi-protocol environment such as this the only real options are to build multiple protocol stacks and applications within each device, and increase the hardware required. However this will only add significantly to the costs of manufacture.

All of which adds layers of complexity to an already complicated solution. With no commonly agreed framework, the decision to go with one or the other could also limit the availability of peripheral devices that can operate within that chosen communications architecture and, by default, the function and features available to the consumer. This is important because consumer engagement has, to date, proved elusive. Recent reports indicate that UK consumers at least, have not taken to the idea of smart meters, never mind the full HAN.

If the energy displays and control devices can be used as a catalyst for ushering in other home automation services then their appeal to a wary consumer base is likely to grow. But this concept of an automated, interactive home is dead in the water if customer choice on particular devices is restricted by communication protocol. The issue of interoperability becomes particularly acute when a customer moves premises and cannot take his Z-wave display to a ZigBee house, or cannot add a new local device or apply for new tariffs. Customers will need to be able to transfer their smart energy-compliant products reasonably seamlessly when they move without having to take into account the network protocol used by their new metering solution.

Aside from the critical issue of customer engagement, the question of interoperable communication standards is also central to the development of a business case for HAN components. This investment model and potential returns from HAN technologies are not yet completely clear. But if the multiplicity of communications standards continue to be represented across the full range of devices, then simple economic theory dictates that prices will remain high, probably prohibitively so. Including more than one type of local communications hardware option in all meters – approximately 50 million in the UK – would not be cost effective even for communications modules priced below one dollar.

Given the options available, there is a very real risk that the notorious Betamax wars will be repeated within the world of smart metering and HANs. As the losers in that particular battle can attest – along with their fellow victims in the CDMA/GSM struggle of a few decades later – making the wrong decision about forthcoming standards can be a costly business.

THE PUSH FOR STANDARDS
And so we arrive at the most important factor behind the comparatively sluggish development of HAN markets in Europe: the different prevailing attitudes towards developing standards for a truly interoperable market. The current US administration has brought together the various players within the smart metering and HAN spaces, metaphorically bashed their heads together and told them in no uncertain terms to work together to develop a set of standards and an interoperable model.

As a condition of the federal stimulus fund handouts, the US National Institute of Standards (NIST) has taken ownership of smart grid standards in the US – which includes those pertaining to HANs – and its interim report on the smart grid operability of June 2009 outlines the first dozen of what will eventually be hundreds of standards. It also begins to define the various stakeholder groups, their self interests, what they know – and what they don’t – about smart grid issues previously outside their own particular silo in a strong effort to bring together utilities, IT and telecom companies and niche component vendors. The NIST mandate is to deliver an initial, completed roadmap, with standards set and a certification framework in place by the end of the year. Implementation is due to start in 2010.

This compares favourably with the lengthy, red-tape bound process of developing standards in Europe. Here European technical committees, sub-committees, working groups and project teams are mirrored by national committees to agree a European communications standard within nine months, and a standard for additional functionalities within 30 months. Where the Americans are proposing to start implementation, the EU will have a progress report.

Developing the framework in which a competitive market for home area networking can flourish by attracting investment and innovation is fundamental to its success. It is our belief that the comparative lack of progress made within the EU, and among its member states, on setting those parameters through the creation of essential communications standards is the key factor behind the continued predominance of the US in the field.

HOME ENERGY NETWORKS: PRIMARY WIRELESS COMMUNICATIONS PROTOCOLS

ZigBee

ZigBee is an open global standard, widely accepted by the smart meter community, that has been developed by the ZigBee Alliance for low cost, low power wireless mesh networking for monitoring and control. The ZigBee Smart Energy Profile, built on top of the protocol, defines the set of messages that compliant devices should understand and thus defines interoperability standards. ZigBee is based on IEEE 802.15.4 standard MAC and PHY, and is typically available as a system-on-a-chip (SoC) single chip solution; a network co-processor solution; or dual-chip solutions with an RF transceiver. The ZigBee protocol defines the first five OSI layers, and transmits 128-byte data packets at 250 kbit/s. It operates at 868Mhz but is almost universally used at 2.4 GHz. It supports Last Mile communications within a 1km line of sight range. SoC devices typically cost $3 - $4 at volume.

Z-Wave

Z-wave is a propriety-standard wireless control mesh networking technology, driven by the Z-wave alliance. It is available as low cost, low power system on a chip (SoC) solution. It consists of the PHY, MAC, NWK and Device class OSI layers, and offers 40kbit/s data communication rate, with 100 kbit/s available in the 4th generation single chip. It operates at the 868MHz frequency in Europe, with additional 2.4GHz support for regions without permitted sub-1GHz bands. Z-Wave integrates directly with TCP/IP based WAN technologies for last mile communications. It costs between $2 and $3 in high volumes, and $3 - $4 for a complete module in high volumes.

Wavenis

Wavenis is a wireless connectivity platform that features Ultra-Low Power and Long Range coverage capabilities. The Wavenis API can handle most of proprietary or standard application protocols. It has a typical data transmission speed of 19.6 kbit/s, up to a maximum of 100 kbit/s, and operates at 868Mhz. Wavenis is available on OEM cards, OEM platforms and white labelled modules including battery power end points, autonomous range extenders, IP or GPRS gateways and remote monitoring software. Wavenis modules with up to 25mW output offer 1km line of sight support for the ‘Last Mile’ of a utility’s WAN. 500mW power class modules offer a range up to 4km. Fully mounted and tested OEM cards cost approximately €5.00.

M-Bus

Developed in Germany specifically to support domestic utility metering, M-Bus chip sets operate at 868Mhz, are used throughout mainland Europe and are supported by all major meter manufacturers. The EU has established a standard for M-Bus: EN13757. The M-Bus protocol defines all 7 OSI layers and offers data transfer speeds of 66 kbit/s or 16 kbit/s (wireless M-bus) or the much lower 2400/300 bit/s (wired M-bus). M-Bus is not applicable for the ‘Last Mile’ of a utility’s WAN and is suitable for ‘in home’ communications only. There are also some issues relating to interoperability that must be addressed. M-Bus is available as a radio chipset with embedded protocol stack, and costs approximately €3.50 for a bi-directional solution. A single radio chip costs approximately €1.50.

Other networking protocols and solutions include:

  • ANT;
  • BACnet;
  • Bluetooth;
  • EkaNET;
  • HomePlug;
  • INsteon;
  • ISA100.11a;
  • KNX;
  • OneNet;
  • OpenTherm;
  • PhyNet;
  • Sensinode;
  • SimpliciTI;
  • WiFi;
  • Wireless HART.