Wi-Fi versus WiMAX
Smackdown, or merely a matter of choice?
In the same way that one smart grid does not fit the needs of all utilities, neither can one communications network do the job for all.
There has been a lot of buzz around Wi-Fi and WiMAX. Some say it's akin to comparing apples to oranges, and I would have to agree. It all comes down to the business case for each utility, and what type of telecommunications protocol-direct client connections over fiber or wire, or wireless mesh networking (and if wireless, what type) best suits the utility's distinct needs.
Point-to-multipoint wireless mesh networks, whatever their flavor, generally offer reduced infrastructure costs, improved wireless coverage and high resiliency. Different forms of mesh networks have been introduced for smart grid applications such as advanced metering infrastructure (AMI) or home area networks (HANs).
Without delving deeply into the technical differences between the two protocols, Wi-Fi and WiMAX are both open standard, though the cost to deploy the technology is lower, at the moment, to deploy Wi-Fi than it is to deploy WiMAX.
Wi-Fi Direct, expected to be launched by the end of this year, will most certainly introduce new ways in which to support smart energy in the home. A peer-to-peer technology, it will allow communications from device to device. Greg Ennis of the Wi-Fi Alliance told me that it "can be essentially like a dedicated network for the utility within the home."
Wi-Fi is, therefore, going head-to-head with ZigBee within the home, there's a lot of room to play for both parties. Some utilities are adopting the low power ZigBee communication standard, while others are opting for Wi-Fi, given its already widespread use.
And Wi-Fi, as we know, is applicable not only in HAN, but also in Neighborhood Area Networks (NAN) and Wide Area Networks (WAN). Ennis says the economics of scale are driven by cost-effectiveness. Wi-Fi is being used by some utilities not only for their AMI networks, but also third-party applications like Google PowerMeter.
There are some who say that Wi-Fi will take a back seat to WiMAX, however. One reason proffered is that, while Wi-Fi has been shown to be a secure technology, it is unlicensed. WiMAX, on the other hand, offers a secure connection over a licensed spectrum, something utilities may consider a more comforting option, despite the studies and documentation noting Wi-Fi's level of security. (The reasoning, while not scientific: If it looks like an apple, it must be an apple; if it looks like an orange, it must be an orange.)
As well, WiMAX offers a long-range, high-bandwidth wireless option, also attractive to the specific needs of some utilities.
Until recently, WiMAX has not been a communications option for utilities building their WANs. But, as earth-2tech's Katie Fehrenbacher pointed out late last year, with the incursion of new players in the WiMAX arena and the subsequently growing WiMAX network, the costs to employ should start to drop in the near future as economies of scale push them down.
There are utility examples on both sides of the Wi-Fi/WiMAX board. The City of Burbank Water & Power, for example, chose a secure Wi-Fi mesh network for its smart grid upgrade project (financed in part by a $20 million Smart Grid Investment Grant by the U.S. Department of Energy).
And in 2009, Silicon Valley Power (SVP) purchased the Santa Clara Wi-Fi assets to pioneer a meter reading program using the existing Wi-Fi access points. (The system also offers free outdoor Wi-Fi service to the surrounding neighborhood.)
For SVP, it was a matter of cost: when it purchased the Wi-Fi network last year for $205,000, SVP felt that purchase price saved the utility half a million dollars and years worth of time, as opposed to starting from scratch.
On the other hand, CenterPoint Energy decided it needed more bandwidth for distribution automation, and turned to WiMAX, opting for a self-contained, utility-owned WiMAX system, rather than a public one. In fact, according to Rick Nicholson, vice president of research for IDC Energy Insights, CenterPoint was the first utility in the United States to "put a stake in the ground" around WiMax. (Two utilities in Australia, SP AusNet and Energy Australia, are testing WiMax smart meters using public WiMAX networks.)
Oklahoma Gas & Electric and Pennsylvania Power & Light are also working on WiMAX-based smart grid networks. San Diego Gas & Electric and Southern California Edison also plan to use WiMAX for part of their smart grid networks.
What is comes down to is a matter of cost, choice and need. While the Wi-Fi/WiMAX war may wage on in wireless communication circles, utilities will continue to choose the network that best suits their needs, and the needs of their consumers.
This article originally appeared in the November/December issue of Intelligent Utility magazine.
Kate Rowland
Editor-in-chief
Intelligent Utility magazine
krowland@energycentral.com
720.331.3555
Twitter: @katerowland2
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