Smart-grid investment already has paid off for some. When a derecho—a broad, summertime, straight-lined, fast-moving squall line—roared through Chattanooga, Tenn.'s 600-sq-mile service area last July, the publicly owned utility EPB recorded nearly a quarter of its 170,000 customers had been knocked offline.
But the situation would have been much worse had the utility not begun to upgrade its system with $52 million worth of smart-grid tech, including software automation and 1,200 automated switches from S&C Electric Co., Chicago. S&C's IntelliRupter switches "can talk to each other," says Jim Glass, EPB manager of smart-grid development. Outages trip switches immediately up and down the line, redistributing power via alternative routes. The smart switches wirelessly report the outage location to a command center.
"We can immediately dispatch crews to a specific location to begin repairs," says Glass. "Before we added the new gear, 25% of our effort would be spent on sending scout teams out for visual inspections to find downed lines and pinpoint outages before sending out repair crews. Now the outages are already isolated." The upgraded system not only slashes the number of outages, he adds, it also minimizes the time required to restore power to customers.
EPB's improved distribution system is "smart …interactive and self-healing," says spokeswoman Danna Bailey. By analyzing data from smart meters and the SCADA system, the utility conducted a post-storm assessment. The results offered a dramatic validation of the spending: $1.4 million in operational savings and a 55% reduction in outage duration.
EPB's ability to quantify the financial benefits of smart-grid equipment should help investor-owned utilities make a business case to public service commissions for capital programs, says Mike Edmonds, vice president of strategic solutions at S&C. Publicly owned utilities such as those in Chattanooga and Napierville, Ill., already are "deriving benefits [from smart-grid investment], but many investor-owned utilities are unable or unwilling to commit," Edmonds says. In some cases, the failure is a utility's short-term strategy based on quarterly returns; in others, it's the recalcitrance of commissions to approve rate hikes.
Edmonds believes some smart-grid money could be spent more wisely. "Too much of the DOE stimulus grant money went toward AMI [advanced metering infrastructure]," he says. Unless the last segment of the electricity chain—distribution to the end-user—is configured smartly, with advanced switches and capacitors capable of self-healing in upset conditions, "then you don't really have a smart grid."
And even though at the fringes of Sandy's path utilities—such as PEPCO in the Washington, D.C., area—used high-tech controls to identify outages and restore power quickly, a smart grid is of minimal value when major chunks of the transmission and distribution infrastructure are taken out, Edmonds says.
David J. Manning, senior vice president with the New York office of engineering consultant Vanasse Hangen Brustlin Inc. and executive director of the New York Smart Grid Consortium, agrees but says utilities, even those now rebuilding in the devastated storm zone, will see smart-grid technology quickly pay for itself. "The drivers are reliability and cost," he says. "After Sandy, I think people will see it as reliability with a large R and cost with a small c."
