Florence Could Provide First Test of Dominion’s Undergrounding Program

Image source: Dominion. Click for larger image.

Hurricane Florence may not be the cataclysm for Virginia that everyone anticipated two or three days ago. Forecasts suggest that the hurricane will veer west, not north, when it hits the Carolina coast. But other hurricanes are spawning in the Atlantic Ocean, Virginia is still a potential target, and it is still worth exploring the implications of Dominion Energy’s grid transformation program for disaster preparedness.

A big part of Dominion’s proposed multibillion-dollar grid modernization program involves hardening infrastructure and burying vulnerable distribution lines to reduce the frequency and length of electricity outages in the event of a natural disaster.  The utility already has buried hundreds of the most outage-prone tap lines under a pilot program launched four years ago, and it proposes under the Grid Modernization and Security Act to bury thousands more, funded by profits over and above the level to which it normally would be entitled, in an expansion of the initiative.

No investments have been made under the auspices of legislation passed earlier this year. Dominion has submitted its modernization plan to the State Corporation Commission (SCC) for review, and it doesn’t expect a final order until January.

But Hurricane Florence could provide a test case for the value of the strategic undergrounding program. Over the past four years, Dominion has buried 968 miles of electric line. While undergrounding obviously increases reliability for the customers directly affected, there is a system-wide benefit, explains spokesman Rayhan Daudani. “The system wide benefit is seen when we can reallocate crews more quickly and respond to outages more quickly than we would have been able to before. Fewer down wires means fewer repair locations, which means our crews can respond to the outages remaining, restoring service more quickly for all customers.”

According to data filed with the SCC, distribution lines incorporated into the strategic undergrounding program experienced 29 outage events in 2017. That compares to 1,683 events that were predicted to have occurred in the absence of the burial program. The average outage duration for customers served was 1.05 minutes compared to a predicted 386 minutes.

The Dominion-supplied graphic above shows how the undergrounding program fits into larger disaster recovery efforts. The red bars schematically show the length of restoration time before the Strategic Undergrounding Program (SUP) and the green bars the length of time after. How accurate a reflection of reality this schematic is, I do not know, but it conveys what Dominion is talking about.

On a side note… For rate payers, there may be a silver lining to those hurricane storm clouds. In the past, the repair of storm damages was incorporated into base rates base and passed along to ratepayers. Under the Grid Modernization Act, Dominion’s base rates are frozen. If Hurricane Florence causes millions of dollars worth of damage, the utility will absorb the cost of repairs and restoration.