Across Florida and the rest of the Southeast, millions are without power after Hurricane Irma lashed the region with winds over 100 miles per hour, heavy rains and destructive storm surge.
Much of the grid damage is the result of gusts toppling trees and sending branches flying, weaponizing them as shears that can easily slice through power lines strung along poles, according to Bloomberg. That spells trouble when about 60 percent of power lines for Florida Power & Light (FPL) — the largest utility in the state — are above ground and in the path of fallen trees.
In FPL’s service area alone, hurricane damage caused at least 5 million outages and damaged all 27,000 square miles of FPL’s grid, according to Bloomberg — and it could take weeks to restore power.
Now some are wondering: Why leave power lines above ground at all?
The short answer is that it’s expensive to get them underground. It can cost up to ten times more to bury power lines than to put them up above ground, according to CNN. That’s as much as $1 million more per mile to put lines above ground rather than below, NPR reports.
“While I would love to see the entire system underground, I think it would be cost prohibitive,” Rob McGarrah, general manager of Tallahassee's electric department, told the Tallahassee Democrat last year. “We've got to balance cost and reliability. And it would be very costly.”
But even if U.S. utilities put all power lines underground, they wouldn’t necessarily be safe from hurricanes, which have more than just high winds in their arsenal.
Severe flooding and storm surge can also put the grid out of commision after storms, according to NPR.
“You're simply trading off one type of risk for another,” Ted Kury, an energy expert at the University of Florida, told NPR. “Yes, you've mitigated the risk of losing power because of a failure in the pole or a tree getting blown into the lines. But you've traded that risk off for outages due to storm surge or to flooding.”
Across the country, only about 20 percent of U.S. power lines are underground, the Energy Information Agency reports.
Compare that with Germany, where nearly all low- and medium-voltage lines are buried safely underground, providing electricity to homes and apartments across the country, according to CNN. That’s led to fewer outages in Germany, CNN reports — but then again, the northern European county doesn’t deal with hurricanes.
For now the focus is on restoring power, and the task is a daunting one. More than 30,000 utility workers have been activated to assist in restoring power, as the Bradenton Herald reported Monday.
“It’s a magnitude we just haven’t seen before,” Eric Silagy, CEO of FPL, told reporters on Monday. “This is the largest restoration in the company’s history.”