Undergrounding Case Study: Hilton Head Island
Hilton Head Island

Hilton Head Island Project Puts Power Lines Underground

One of the country’s most inspiring and forward-looking municipal improvement projects took place in the Town of Hilton Head Island, South Carolina, where crews completed a 17-year project to put overhead power lines underground.

The effort results from a 2004 Town ordinance requiring the conversion of all overhead power lines to underground. The project was designed to protect the health, safety, and welfare of residents and visitors, increase the reliability of electric service, and boost the local economy by improving the aesthetics of an island that receives more than 2.3 million visitors annually. The project was completed on August 31, 2021, with the removal of the final aboveground pole. 


Hwy 278 at Palmetto Dunes before undergrounding
Hwy 278 at Palmetto Drive after undergrounding

Scope of the Project

Putting the utility lines underground decreases the need and expense of vegetation management and increases the reliability of service. In 2017, Hurricane Irma wreaked havoc on Hilton Head, but the sections that had been undergrounded already were back up and running after the storm, whereas standing power lines had to be entirely reconstructed. 

The conversion process relied on a partnership between the Town and the utility company Palmetto Electric.  The project’s funding came from a 3% monthly fee for the utility bills of the roughly 1,800 commercial and 35,000 residential customers on the Island.

With this project, 3,574 poles and 1,238 overhead transformers were removed and 115 miles of overhead distribution lines were converted to underground at a cost of $34,777,000. Hilton Head is using trenchless directional boring which reduces the impact on the existing infrastructure and vegetation in the area. Town officials also coordinated the project with other road work taking place, reducing the need to do unnecessary work to place the lines. 

Hwy 278 at Sea Pines Circle before undergrounding
Hwy 278 at Sea Pines Circle after undergrounding