Wireless home sensor network finally possible
By Erich Gunther
Jan 30, 2008 - 3:00:00 AM

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Date of Tech Take: January 30, 2008

 

In SGN's Tech Take articles, power engineer and architect Erich W. Gunther evaluates actual products and services against the SGN Smart Grid Scorecard. Unless disclosed explicitly at the beginning of the article, neither SGN nor Erich Gunther has received any compensation from the vendor nor do they own stock in the company.

 

Tendril Network Operating Platform speeds up deployment of Zigbee apps

This article examines the Tendril Network Operating Platform (TNOP) Version 2.0 (see the displays at the end of this article) a software platform for building applications and controlling wireless sensor networks based on the ZigBee industry standard. Now in its second major release, I believe that utilities, systems integrators and manufacturers can use TNOP 2.0 to speed up the process of deploying effective ZigBee based applications and their associated home and facility area networks. To understand my evaluation, you need to grasp three essential elements:

·         The role of the SGN Scorecard

·         The purpose and components of an home area network

·         How TNOP measures up

 

The role and importance of the SGN Scorecard

The SGN Scorecard was developed for a very important reason: most of today's products do not adhere to Smart Grid principles. They do not support the requirements envisioned by Smart Grid researchers such as EPRI, the California Energy Commission's Public Interest Energy Research program, the Modern Grid Initiative and DOE's GridWise program. Nor do they adhere to the mandates in the Energy Independence and Security Act of 2007. 

 

In particular, several elements of the EPRI IntelliGrid Architecture are critical to implementing a Smart Grid:

·         Proven, Internet derived communication technologies

·         Service based architecture at the enterprise level

·         Self healing technology

·         Well defined interfaces and points of interoperability

·         Application of industry and international standards

·         Built in security and network management

 

In the last edition we evaluated a backbone network infrastructure from Silver Spring Network. Now, we go beyond the meter into the home to evaluate software platform for controlling wireless sensor networks.

 

Whether you realize it or not, wireless sensor networks are going to be key to the wide spread roll out of advanced metering. To date it has been very difficult to integrate devices to wireless sensor networks. An additional problem is that system integrators and ZigBee device vendors spend a lot of time developing low level programming code to support each application they develop. Absent internal discipline, this effort is duplicated many times.

 

SGN Warning: To avoid buying dead-end products, utilities must provide their vendors with a comprehensive and prioritized list of requirements covering current and future functionality. Then they must get written assurances from vendors that their products meet those requirements.

 

The SGN Scorecard is a checklist that measures whether products meet minimum standards for a Smart Grid. We will use it as the benchmark for all Tech Talk reviews. You are invited to use it free of charge for your own evaluations. For a further explanation and a blank version you can copy freely, download the PDF version of the Scorecard.

 

The purpose of a home area network

The facility or home area network (HAN) is where the rubber hits the road in terms of enabling smart grid applications for the consumer.  It allows multiple devices to cooperate with each other to fulfill complex functionality such as whole house energy management, or can simply provide a means to deliver utility prices to home devices so they use energy when it is least expensive.

 

In a home area network, multiple components interact to provide a wide range of capability.  The basic components of a home area network are:

 

1. The network portal or gateway that connects one or more outside information services to the home area network
2. The access point or network nodes that form the wired or wireless network itself
3. The network operating system and network management software such as ZigBee and the TNOP
4. The end points such as thermostats, meters, in home display devices, and appliances  

Tendril product lineup

The Tendril Network Operating Platform (TNOP) 2.0 is a extensible software platform for deploying and managing ZigBee based sensor networks and the applications based on the ZigBee standard that make them useful (e.g. direct load control, demand response, residential and industrial energy management). TNOP, the application suite has been available for about two years. Although not reviewed in this article, Tendril recently introduced a suite of applications that utilize their own platform including:

 

Tendril Deploy -- is a ZigBee commissioning software tool that provides the simplest way to install a ZigBee application and its devices.

Tendril Monitor -- is a ZigBee-compliant monitoring and diagnostics software tool that offers deployed ZigBee application monitoring and diagnostics statistics. With a default GUI, Tendril Monitor can be used as a stand-alone application.

Tendril ePortal – is a browser-based application allowing the consumer to better understand, manage and control the energy consumption in their home

Tendril Utility Energy Management Portal -- provides administration services to the Energy Management System and integration points to the utility’s back office enterprise information systems 

 

Evaluating TNOP – the application suite

TNOP 2.0 provides a higher level set of programming interfaces that allow manufacturers and system integrators to focus on application details rather than on the minutiae of bits and bytes manipulation at the protocol level. In addition to the Tendril application suite, the open standards based interfaces allow – and Tendril encourages – third party application development to extend the platform. Tendril claims that the platform can reduce the time it takes to build ZigBee applications by 80%. Warning -- While not having had an opportunity to confirm this claim, I recommend that you consider an open system platform such as TNOP before you build your own system.  

 

TNOP compared to competitors

TNOP is more comprehensive and focused on enabling rapid application development and deployment. Tendril’s closest competitors are Atalum (a Spanish company) and Daintree ( Fremont, California) but their offerings are not as mature or comprehensive as the TNOP nor do they embrace open standards and well defined points of interoperability to the same degree as Tendril.

 

Where you need to be careful with TNOP

TNOP is the first of a new class of product for ZigBee system and application development so it is difficult to compare with other products on the market. Tendril recently announced and demonstrated at Distributech the first comprehensive application based on the Tendril Network Operating Platform – the Tendril EMS. The first ‘in-home’ deployments of the Tendril EMS are expected to occur in Q1 2008. Tendril’s web based portal of the Tendril EMS is also currently being showcased at CenterPoint Energy’s Technology Center. You should keep an eye on these developments if you intend to integrate home area networks into your offerings.

 

SGN’s Smart Grid Checklist:

Tendril claims to use open, standards based technologies to create an extensible platform suitable for deploying a wide range of applications independent of underlying technology implementation details. Our analysis based on our metrics generally confirms this claim. In general, TNOP embodies key elements of the EPRI IntelliGrid Architecture which we believe are key to implementing the Smart Grid through well-integrated applications:

 

►        Service based architecture

►        Technology layering and isolation

►        Well defined interfaces and points of interoperability

►        Application of industry and international standards

►        Distributed computing (agents)

►        Network and systems management

 

TNOP’s Smart Grid Checklist scores -- total score of 86 (out of 100)

Metric	1-10 (10 is best)	Comments
Impact	9	Significantly reduces time and cost to develop and deploy ZigBee applications
Openness	10	All interfaces are well documented allowing third party plug-in development
Standardization	8	All interfaces and internal architecture and technologies are standards based
Security	6	Security has been built into the core, but not yet mature or proven
Manageability	10	A core feature is managing ZigBee infrastructure, applications, and itself
Upgradeability	8	The modular nature of the platform simplifies upgrading the product
Scalability	6	Scalability is designed in but remains to be proven in a fielded application
Extensibility	9	The modular nature of the platform inherently provides extensibility
Self-Healing	10	ZigBee mesh networks are inherently self-healing when properly deployed
Interactivity	8	This metric is based on the web portal view of the Tendril EMS
Date of product: March, 2007. TNOP has the following part number and revision: TNOP 2.0

It will take time to see if the market validates the promise of the TNOP beyond the meter.   

 

 

Erich W. Gunther is Chairman of EnerNex Corporation. He chairs the UtilityAMI / OpenHAN standards group and serves on the GridWise Architecture Council.

 

   Email Erich W. Gunther

   Smart Grid Scorecard (PDF)

   EPRI IntelliGrid Architecture Web site

   GridWise Architecture Council

   Tendril Web Site

   Atalum Web Site

   Daintree Web Site

 

 

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