(CNN) -- The majestic trees that line streets across the American South are a beautiful sight most of the year.
Then there are the weeks when a winter storm hits, and the trees shed ice-laden limbs that crash down on the power lines below. It's at those times when millions of normally genteel Southern voices rise as one to ask, "Why aren't these &@$#*%! wires underground?"
In one word: Money.
After a 2002 storm that knocked out electricity to 2 million customers in North Carolina, regulators there took a look at what it would cost to bury the three major power companies' overhead lines. The state Utilities Commission concluded the project would be "prohibitively expensive."
"Such an undertaking would cost approximately $41 billion, nearly six times the net book value of the utilities' current distribution assets, and would require approximately 25 years to complete," the report states. Customers' rates would have to more than double to pay for the project, the commission' staff found.
And underground lines "are not without their disadvantages," they concluded. While more reliable "under normal weather conditions," they take almost 60% longer to fix when something does happen to them.
Underground power lines make up about 18% of U.S. transmission lines, according to the federal Energy Information Agency. Nearly all new residential and commercial developments have underground electric service, the agency said. But it noted that underground power lines cost five to 10 times more than overhead wires, don't last as long and cost more to replace.
"Buried power lines are protected from the wind, ice and tree damage that are common causes of outages, and so suffer fewer weather or vegetation-related outages," it concluded. "But buried lines are more vulnerable to flooding, and can still fail due to equipment issues or lightning."
But there are some places that have decided to go ahead and dig.
In Anaheim, California, the city is gradually burying its above-ground power lines, a project that dates back to the 1990s. The city added a 4% surcharge to electric bills to pay for the 50-year project, which costs more than $3 million a mile.