Why Utilities Tiptoe On the High Wire Of Service Reliability
It is the summer of our disconnect.
In New England, where five of eight nuclear power plants are off line for safety reasons, utility officials are keeping their fingers crossed. So far, cool weather has helped check demand for electricity, forestalling brownouts or selective blackouts.
In the West, where generating electricity is not a problem, utility and government officials met Aug. 12 in Portland, Ore., to draw lessons from the region's second major blackout in less than two months. The latest outage hit more than 4 million people from California to Texas and from the Mexican to the Canadian border. Traced to weather-related problems in the transmission system, the blackout was one of the worst in US history.
"Nothing like this was anticipated at the beginning of the season," sighs Gene Gorzelnik, spokesman for the North American Electric Reliability Council (NERC). The council, based in Princeton, N.J., sets operating standards for utilities and nine regional councils that serve as travel agents for electricity humming over high-voltage lines in their areas.
He says that because of the plant outages, planners were anticipating the most trouble in New England - particularly in Connecticut. New England as a whole has drawn electricity from Hydro-Quebec and from utilities in New Brunswick to help make up the shortfall in generating capacity. But Connecticut, home to four of the out-of-service nuclear plants, has few incoming transmission lines. Ordinarily, with so much generating capacity the state has always exported electricity, says a spokeswoman for the state's Public Utility Control Department.
Foreseeing the shortfall in generating units, utilities regionwide either accelerated maintenance or postponed it until September to ensure that as many power plants as possible were available this summer. In Connecticut, Northeast Utilities brought mothballed fossil-fuel plants on line. Even the US Navy got into the act, using generators for its submarine base in Groton to avoid drawing heavily on the state's grid.
The results have paid off - if barely. "We've all been dodging bullets this summer," says a cautiously relieved Karen Bernardino, spokeswoman for New England Electric Company, a utility based in Westborough, Mass.
The same can't be said for the western US, which has taken two hits.
The first came as a regionwide blackout July 2, affecting 2 million people. According to the Western Systems Coordinating Council and a US Energy Department report ordered by President Clinton, a combination of high demand, hot weather, and an errant pine-tree limb in Idaho led to a short circuit in a high-voltage line in Idaho. The chain of events set up instabilities that tripped circuit breakers and sensors across the rest of the grid.
But the ink was barely dry on the DOE report when a second blackout hit Aug. 10. Another spate of hot weather and high demand led to random outages in Washington and Oregon. These set up instabilities in the grid that prompted an automatic shutdown of the four major high-voltage lines feeding into northern California. Once again, the problem cascaded.
Utility industry officials say part of the problem lies in transmission lines that are getting strenuous workouts. The lines were installed at a time when utilities served a limited region. Little was shipped beyond a utility's home turf. Over the past decade, the portion of power sold outside a utility's territory has grown from 10 percent to 50 percent. But few new transmission lines were installed because of difficulties in getting permits.
As a result, during the peak summer periods, these lines run close to capacity. When they get hot, they sag. High-voltage transmission lines also can lose voltage through the interaction of their magnetic and electric fields with the earth.
Reliability is going to become more critical as utilities become more competitive in a deregulated market, warns Marija Ilic, a senior energy research scientist at the Massachusetts Institute of Technology in Cambridge.
If lines cannot be added, more effective use must be made of existing lines through the use of computer-based technologies that can reroute electricity or make other adjustments the instant problems arise, she says. Moreover, some form of regional or national coordination will be needed, she says, because interconnections still leave one part of a grid at the mercy of events of another part, regardless of the owner.