Before we start the discussion of underground versus overhead electric lines, I think it's important to recognize that our electric reliability is among the best in the nation. Our customers have access to power 99.99% of the time.
In the 1970s, our city leaders passed an ordinance requiring all new developments be connected to underground electric services. In addition, we have several programs in place for the gradual conversion of overhead to underground. Today, more than 77% of our electric system is underground.
The question of accelerating the undergrounding of our remaining overhead lines has merit. Underground systems are protected from strong winds and falling trees. They also look better aesthetically.
However, buried lines are susceptible to water and excavation damage, and can take longer to repair because the damaged area is usually more difficult to locate.
Installing buried lines can also cost several times more than overhead lines, especially in established neighborhoods with older trees and limited space and easements.
Undergrounding the remainder of our electric system will cost an estimated $2.2 billion, an expense likely paid by all customers in the form of higher rates. This does not include the cost customers might incur to retrofit their homes and businesses to safely connect them to a new underground system.
Comparing overhead to underground systems, reliability numbers are closer than you may think. About 51% of our outages occur on our overhead system; 49% is attributed to faults on the underground system.
Our Utilities Board is continually addressing the cost/benefit of our undergrounding efforts by funding existing programs and adding new ones.
As a community-owned utility, we will continue to listen to our customers on this important issue and invest in our infrastructure while keeping rates affordable.