After nearly every major storm event resulting in major power outages, utilities, public officials, and customers reexamine the existing electrical distribution infrastructure. And no exception, the most recent hurricanes, Harvey in Houston, Irma in Florida, and Maria in Puerto Rico, have reignited the debate over buried lines and whether the risks are worth the investment.
When Harvey hit Texas, Houston had almost 24,000 circuit miles of underground distribution lines and roughly 26 circuit miles of underground transmission, but still had over 28,700 pole miles of overhead distribution lines and 3,600 circuit miles of overhead transmission. The underground lines may have contributed to local utility providers’ ability to restore power quickly, but according to an energy economist at the University of Houston, other factors such as technology (like smart meters) and maintaining preventative measures (like tree-trimming) may also have helped as much or more.
Meanwhile, in Florida, utility providers said that when Irma hit, they benefited from “a decade of work to protect and harden their power grids, an effort that included putting some distribution lines underground.” Palm Beach has approved plans to invest roughly $90 million to place all power, telephone and cable lines underground.
Finally, Puerto Rico finds itself in a position of having to reconstruct almost all of its distribution lines, and most of its transmission grid, from scratch. This tragic situation, however, creates an opportunity to explore a variety of options – from buried lines, to distributive generation, to micro-grids with battery storage, to increased utilization of renewable resources – without the financial burden of sunk or stranded costs. We will be monitoring how the re-development of Puerto Rico on such a blank slate may inform and guide future investment decisions regarding technology choices and infrastructure deployment on a larger scale in the contiguous states.
In North Carolina, the Public Staff of the N.C. Utilities Commission published a feasibility study in 2003 for placing all electric distribution facilities underground for North Carolina and found the cost to be $41 billion over 25 years and would increase the average customer’s electric bills by 125%. Currently, utilities in N.C. will install underground facilities under various circumstances or at the request of a landowner who pays the full cost of installation.
Burying power lines has aesthetic benefits but requires more upfront cost, can take longer to repair and are susceptible to other risks. Consider this past summer in North Carolina when ACL Construction accidentally cut a major underground transmission cable while building a new bridge across the Oregon Inlet, resulting in major power outages and evacuation orders during peak summer tourism season. Topography, geography and vulnerabilities are all factors to determine whether burying power lines is right for your area and worth the cost.
To read a report published by EEI on underground lines: http://www.eei.org/issuesandpolicy/electricreliability/undergrounding/Documents/UndergroundReport.pdf