Fiber Pays Off in Chattanooga
Last summer, when a series of violent, straight-line windstorms, derechos, hit the Midwest and Mid-Atlantic states, a lot of utilities and their customers suffered terribly. But “one utility that had deployed power interrupters every few blocks was able to vastly limit the impact of those windstorms,” said Mark Madden, Alcatel-Lucent's regional vice president for North American energy markets. “Instead of area-wide outages, they were able to isolate them to a block or so, and I think that is one of the major promises of the smart grid.”
That utility was the Chattanooga EPB, which has Alcatel-Lucent's gigabit-per-second passive optical network (GPON) running past every home in the city. As such, Chattanooga may provide a glimpse of what is possible with what Madden refers to as a “substantial communication infrastructure.”
In fact, when the derechos hit last summer, Chattanooga's smart grid, which relies on 8,000 miles of fiber and nearly 1,200 fully automatic switches, proved up to the task and worthy of the investment. “We learned the capability of automation,” said Jim Glass, Chattanooga EPB's manager of smart grid development. Although 35,000 of the municipality's 170,000 customers lost power during the storm, the utility estimates that 42,000 additional outages were either avoided or restored nearly instantly.
Interestingly, when the city was planning its DA system, it considered two different approaches. “Either the switches communicate with each other, or they communicate with a computer in the back office that then issues commands,” Glass explained. EPB chose the former. “If we had gone the other way,” said Glass, “we would have spent a tremendous amount of time with a vendor building the central brain that would issue all those controls. So, it would have been at the end of the two-year construction project before we saw any benefit.”
Instead, he noted, “we started having successful DA events three months into the project while continuing to build out the system, and we were getting more and more benefit as we added more switches.”
The Promise of the Smart Grid
Although the new normal may be an increasing frequency of violent superstorms like Sandy, there is no doubt those storms have proved the value of a smart grid. But as Alcatel-Lucent's Madden noted, “While smart grid technology offers utilities the opportunity both to improve reliability and to reduce the impact on consumers, the extent the smart grid can be deployed and its success is almost entirely dependent on the capabilities of the communications systems.”