Oklahoma Weighs ‘Undergrounding’ Options For Power Grid

By Jeff Griffin, Senior Editor | August 2008 Vol. 63 No. 8
Ice storms frequently cause major power outages and can be costly and difficult to repair quickly. (Photo courtesy Public Servic

The Public Utility Division of the Oklahoma Corporation Commission (OCC) has completed an investigation into measures that could be taken to protect the state's power infrastructure from ice, wind and other disasters that have the potential of disrupting electrical service. Some of the measures could have a substantial impact on underground construction.

The three member commission held a public hearing on the issue June 30. No action was taken, but commissioners requested its staff to prepare recommendations about which measures suggested in the study should receive priority and to prepare estimates of the costs for implementing them.

The study was undertaken early this year after a December 2007 storm knocked out power to more than 620,000 electrical customers in the state. Some residents and businesses were without electrical service for several weeks.

One of the questions raised following the late 2007 storm was why more of the state's power lines are not underground where they would be protected from weather related risks. Costs and other issues related to placing more power lines underground were focal points of the study.

Key findings

A preliminary summary of the report released by OCC cites key findings:

• Climatological data support the theory that Oklahoma will experience an increase in the number of storms likely to disrupt electrical service;
• Full immediate undergrounding of transmission and distribution infrastructure would be too costly to be feasible;

• Efforts to increase the ability of the state's electrical delivery systems to better withstand such storms should be multifaceted and target undergrounding, "hardening" infrastructure and improved vegetation management. Hardening is defined as improvements to equipment that will minimize weather related damage.

The Public Utility Division staff recommends the commission institute legislative and rulemaking processes to determine the feasibility, support and exact requirements for 12 measures:

1. Bury drop [service] lines and/or create a pilot program to test newly available service entrance/disconnect systems.

2. Bury all new lateral distribution lines.

3. Bury existing lateral distribution lines when requested by a majority of customers in a neighborhood.

4. Identify "fully urbanized" main distribution lines [lines that are at capacity for lateral line connections] and require their burial when the line is replaced as part of normal maintenance or repair.