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 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.