Going green is a major trend that is impacting all of our businesses. In the last year, we have seen more companies jumping on the green bandwagon then ever before. However, since day one, ZigBee technology has been focused on green issues. Among other things, ZigBee technology is ideal for sensing and controlling energy consuming devices, such as lighting and heating/ventilation/air-conditioning (HVAC), in both home and commercial buildings. Now that the world has become more concerned with rising energy costs, which have gone up 4X in the last 30 years1, it is clear that ZigBee technology is increasingly viewed as a leading technology to help reduce energy cost in home and commercial buildings through Smart Energy products.

Energy Usage Outpaces Energy Generating Investments

The U.S. is a major consumer of electricity, and demand has increased 25 percent since 1990 while annual investment in generating electricity has decreased 30 percent in the same time period2. While some may say we need to increase supply through the building of new generation plants, or even through alternative energy sources (wind and solar power) that takes time and costs billions of dollars. An alternative is to try to control the amount of energy used. Energy can be 20 percent3 of a building's operating cost, with lighting and heating/cooling using most of it in both residential and commercial buildings. They are prime targets for energy reduction through smart energy usage with lower energy components.

A study by the U.S. Department of Energy's Pacific Northwest National Laboratory showed that households with digital tools controlling temperature and price preferences saved on average 10 percent on utility bills while cutting peak loads on utility grids by up to 15 percent. This translates into $70 billion dollars saved over a 20 year period on new power plants and infrastructure expenditures. Utility companies are looking for smart ways to control rising energy usage while limiting capital expenditures. Utilities are looking to implement both load control and variable pricing to help manage load during peak times. Through load control, utilities companies can turn off customer loads, such as HVAC, for sort periods of time (a few minutes) during peak loads. In addition, utility companies can employ demand response, which allows them to communicate changing utility rates to the home to encourage voluntary energy conservation. These actions will help prevent rolling brownouts by reducing peak demand.

ZigBee technology helps address both these needs with an open and interoperable standard for communication from the utility to the home area network (HAN) for purposes of load control and demand response. This allows ZigBee-enabled meters to communicate and control ZigBee enabled devices in the home, such as the HVAC system. The home owner will also have the option of taking voluntary actions during demand/ response periods to reduce their personal consumption by turning off appliances, lights, etc. This not only reduces the peak load on the utility grid but also helps home owners make smart decisions on their energy use. ZigBee technology can also convey intelligent communication between the HAN and individual appliances to facilitate load control and demand response. For example, a dishwasher can delay its start to a time of day that has lower utility rates.

Regulation Helps Drive Requirements

Regulations and requirements that are being enacted to reduce energy consumption and ensure a more reliable energy grid are helping push the adoption of green technologies. These regulations and requirements are being driven at the federal, regional and state level. For instance, the Energy Policy act of 2005 and the Energy Independence and Security Act of 2007 mandate standards for items such as smart metering, grid reliability and energy efficiency in both buildings and appliances. Regional drivers, such as the Electric Reliability Council of Texas, have incorporated requirements for smart grid functionality as well as smart meters. The council has recommended using a HAN for rate recovery with a standardsbased approach, "...such as ZigBee."

We can see even more stringent state-level drivers, with California leading the way with its California Load Control Proceeding (formally Title 24). Utility companies, such as Southern California Edison, are reacting by rolling out five million ZigBee-enabled meters and HANs over the next several years4.

The Savings Add Up

Much of the recent activity targets residential customers. And while it may seem that this is benefiting the utility company more, it also benefits the home owner with reduced consumption and operating expense. In addition, by enabling a more intelligent home, consumers can begin automating such things as lighting control. Lights that are not needed or are accidentally left on can be turned off. Answering a demand/response notification, lights can be automatically dimmed and starting other appliances, such as a dishwasher, oven, coffeemaker, etc. can be delayed. The below example looks at a simple lighting automation for the HAN that shows significant savings.

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• 2,000 Square foot home with 4,500 watts in lighting
  
  • 
    
  • 3 bedrooms x 440 watts
    
  • 2 bathrooms x 460 watts
    
  • 1 kitchen x 460 watts
    
  • 1 dining room x 240 watts
    
  • 2 living rooms use 340 watts
    
  • Other has 880 watts (closets, garage, half bath, outdoor lights, etc.)
  
  
• Typical lights are bathroom, bedroom, closet, or outdoor lighting
  
• $246 annual cost
  
  • 
    
  • 450 watts x 10 hours/1,000 (kilowatts) x .15 (cost per kWh) x 365 (days a year)
    
  • If these 2-3 lights are controlled by a ZigBee-enabled HAN in a Smart Energy home, these lights might only be on a few minutes at a time, saving a considerable amount of the original $246 cost.

Products are Hitting the Shelves

While ZigBee-enabled products for home automation have been on the market for several years, they have been expensive and remained a niche market. However, with the introduction of the ZigBee Smart Energy Profile and the rollout of Smart Energy enabled meters from the utility companies, we will start seeing more products on the market. Initially the rollout will include a ZigBee-enabled meter, thermostat and premise device to communicate pricing information. But soon we will start to see products such as lighting and appliances that can benefit from the Smart Meters and demand response information sent by the utility. Eventually, we could expect to see the home with multiple ZigBee-enabled devices, such as lighting, HVAC, appliances and even security; all communicating with each other and the utility meter.

Freescale Enables Smart Energy and ZigBee Technology

Freescale has an extensive portfolio of ZigBee-enabled ICs and low power MCUs that make up an ideal platform for ZigBee and Smart Energy products. Freescale's MC1322x ZigBee Platform in a Package (PiP) is the latest in a long line of low-power platforms for ZigBee devices. With its best-in-class power consumption and highly integrated packaging, it is becoming the metering companies preferred choice to enable Smart Meters with ZigBee technology.

For customers that need additional functionality or memory, Freescale offers a number of low-power MCUs as well that can be paired with stand-alone transceivers. The Flexis? family of MCUs offers low power and an upgrade path from 8-bit to 32-bit processing power. In addition to ICs, Freescale has taken a platform approach that includes software, development tools and reference designs to help simplify development. Freescale's BeeStack? ZigBee compliant stack with BeeKit? Wireless Toolkit provides a simple software environment to configure network parameters. This tool is unique to Freescale, allowing customers to use a wizard and drop down menus to help configure the ZigBee network parameters. Our competitors force the user to wade through lines of code to edit the network parameters.

Finally, while the MC1322x PiP simplifies RF design, many customers don't have the expertise to ensure robust and optimized designs. Freescale has a number of reference designs, from IC to antenna, that include the design details for the development hardware in the development kits as well as designs that are more "form factor." They can take the bills of materials, gerbers and schematics and simply copy our design or integrate it into theirs. The complete platform approach helps you reduce development time and speed time to market.

Freescale development kits provide the ideal development platform for the ZigBee protocol. The MC1321x and MC1322x are specifically targeted for ZigBee-enabled device development, providing the necessary hardware, software, tools and demo applications to streamline the development process. These kits come with development boards programmed to allow developers to have a ZigBee network up and running in just fifteen minutes. The demonstration is based on Freescale's ZeD (ZigBee enabled Demo) using the Home Automation profile. The kit also comes with the BeeKit Wireless Toolkit and additional demo applications. In addition, for customers running the ZigBee protocol that requires a different low-power MCU, they can use the MC13202 RF transceiver and the Flexis QE128 MCU. The MC1320x-QE128-DSK provides a simple and lowcost development platform and includes a 2-node example using the ZeD HA lighting application.

Summary

With all this activity, it appears that ZigBee technology has found a home in the Smart Energy market. While this is just an example of how ZigBee technology is going green in the home, we expect ZigBee to move beyond lighting and HVAC to other appliances and to migrate to commercial buildings. With Freescale's leadership in ZigBee technology development, our focus on Smart Energy and our relationship with customers, we are positioned for success in this rapidly growing market.

About the Author

Matt Maupin has over 14 years of experience in the high-tech industry focusing on wireless connectivity, including WiFi, Bluetooth and ZigBee. Matt has been active in numerous industry groups for wireless communication and is currently active in the ZigBee Alliance. Matt joined Freescale in 2001.