Last January, the lights in a small section of Oldsmar went out just before 11 a.m. A month later, in the North Florida city of Monticello, power was cut off at 9:23 a.m. Twice that summer, 15 minutes apart, separate clusters of Lake County residents lost their electrical service.
The perpetrators of the outages were longtime enemies of the utility industry, ones that pose an ongoing threat to the grid and have nothing to do with powerful winds from tropical storms.
"Squirrels are one of the top animals that get into our system," said Ana Gibbs, spokeswoman for Duke Energy Florida, which serves each of the areas where the outages occurred.
As unbelievable as it may sound, animals are responsible for a significant number of outages around the country every year. Last year, they caused 4,566 outages for Duke customers in Florida (11 percent of its total outages) and 1,372 outages for Tampa Electric customers (12 percent of its 2018 outages), according to filings with state regulators.
They consistently rank in the top three to five causes of outages for the two major Tampa Bay utilities, often behind only such things as downed trees or limbs, weather events or defective equipment.
Technically, the "animals" category encompasses many critters. Birds, Tampa Electric spokeswoman Cherie Jacobs said, are a particular nuisance for Tampa Bay utilities, especially osprey that like to nest on power polls or transformers. They can accidentally touch a live line, or their nests catch fire. Then there are reptiles, such as snakes and Cuban tree frogs, that get into underground electrical equipment.
Each of the critters pose challenges for utilities, but far and away squirrels are the top adversary. According to the Edison Electric Institute, which represents investor-owned utilities nationally, squirrels cause the most damage of any animal to its members. There's even a site — CyberSquirrel1.com — that tracks squirrel-caused outages around the country and the many news stories that suggest they pose a greater threat to the grid than hackers.
Steven Sullivan, director of the Hefner Museum of Natural History at Miami University, runs "Project Squirrel," a citizen science program that aims to understand the distribution and populations of tree squirrels
Squirrels, he said, like trees because they provide shelter, food and transportation. But when nearby trees become too crowded, young squirrels will look for somewhere less populated.
"We look at trees and the electrical infrastructure as separate things, but to squirrels, what's the difference?" he said. "To a squirrel, (a power line) is just a sterile tree."
Most of the havoc squirrels wreak is from chewing through power lines. They, like other rodents, have teeth that continually grow and need to be whittled down by chewing.
Sullivan theorizes that squirrels' interest in power lines may be in part because of the way the lines taste. Some contain lead in the insulation, which animals perceive as sweet.
"Certain types of bird poop (on the lines) might be tasty," he said. "There's lots of reasons to chew a wire."
When squirrels (and other animals) do interfere with a line, the results aren't pretty. Think charred squirrel, or an animal flung far away by the force of the voltage.
To protect against animals, both Duke and Tampa Electric take steps to enclose portions of their equipment to help keep animals out, place devices on the lines that make it tougher for squirrels to cross them, build separate perches for birds away from power lines and use cone-shaped devices to discourage birds from nesting.
Both attribute a recent drop in animal-related incidents in part to their efforts. Duke saw an 18 percent drop from 2017 to 2018, while Tampa Electric had a 16 percent dip during that period
"Like anything, this equipment can deteriorate with weather, it can fall off, they can chew through it," Tampa Electric's Jacobs said. "None of it is foolproof, but it does mitigate the issues as best we can."
Contact Malena Carollo at firstname.lastname@example.org or (727) 892-2249. Follow @malenacarollo.