Frances Powers Debate on Underground Lines

Sep 21 - Palm Beach Post

About 2.8 million customers lost power during Hurricane Frances, and it will take weeks to arrive at a fair assessment of how well Florida Power & Light Co. did in restoring it. But anecdotal evidence already points to one conclusion: People who had buried power lines had fewer and shorter interruptions of service than people with overhead lines.

The more reliable performance of underground lines shouldn't have been surprising because the same result was apparent last month on the west coast when Hurricane Charley blew through Punta Gorda and Central Florida. High winds and falling trees broke lines strung from poles, while buried connections remained largely intact. Elected officials and emergency managers across the state noticed and are pushing for investigations that will reopen the long- running debate over how electricity companies transmit their power.

The case against burying lines primarily is based on expense. FPL says it costs roughly 10 times more to put lines underground than to hang them from poles. Large transmission feeder lines are especially expensive to bury because of the heat their 138,000 volts can generate. Heat can disperse in the air, but underground, the lines must be encased in pipe and cooled with fluid. That can mean a difference of about $1 million per mile, according to FPL. The company's numbers have been suspect at times, however. Last year, residents in suburban Boca Raton complained about a plan to install overhead lines along Palmetto Park Road and Military Trail. FPL officials said it would cost about $8 million per mile to put the lines underground; but a Palm Beach County study put the cost at about $2.4 million per mile. The right number is probably somewhere in between.

FPL says it is bound by Public Service Commission orders to keep bills as low as possible, and the company can't give underground lines to some neighborhoods and then pass on their cost to customers throughout the system. Communities that want service lines buried have to pay for them, and many have done that. Since Hurricane Andrew struck in 1992, about 70 percent of the new lines installed by FPL have been underground and close to 40 percent of all its lines are now buried, compared with 31 percent 12 years ago. Most of the growth in buried service has been in distribution lines that carry power from the large feeders to individual customers. About 84 percent of new developments are distributing power that way. Those new lines appear to have held up exceptionally well during Charley and Frances.

But underground lines have their vulnerabilities. Flooding can cause widespread failures. When Charley approached land, the Tampa Electric Co. shut down power to the city's downtown businesses because of fears that a saltwater storm surge would damage the underground network. Buried service is superior during high winds, but lines and poles perform better during heavy rains. The roots of a toppling tree also can pull out lines and break connections. Repairmen complain that it's often difficult to locate problems in buried lines that would be obvious if they were strung overhead. Underground lines require special equipment and crews to locate faults and a separate crew to dig up the lines.

The Washington-based Edison Electric Institute released a study this year comparing the two distribution methods. Researchers found that some customers served by 40-year-old overhead lines had better reliability than customers with 20-year-old underground service. Two Maryland utility companies have switched from underground lines back to overhead networks to improve reliability. "When compared to overhead power systems," the report said, "underground power systems tend to have fewer power outages, but the duration of these outages tends to be much longer. The bottom line - reliability benefits associated with burying existing overhead power lines are uncertain and in most instances do not appear to be sufficient to justify the high price tag."

Still, the study was not specific to Florida's unique storm problems, and elsewhere, the rising popularity of buried lines is indisputable. About 90 percent of all new developments in the United States install them, often because of their aesthetic appeal to home buyers. Developers of PGA National in Palm Beach Gardens, for example, paid an extra $10 per foot to put lines underground. Most large U.S. cities rely on buried systems to serve urban areas. The Bahamas has phased in underground lines during the past decade and was able to restore much of its service quickly after Frances hit.

A surge in the debate over power lines is appropriate and overdue. Hurricane-weary cities and counties are right to question FPL and the PSC about the potential benefits of switching systems. Millions of customers who sat for days in hot, dark living rooms deserve to know if it's time for Florida to go underground.