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Diverse Generation Mix
One of the most important ways we ensure reliable service in our electric business is to follow the adage about not putting all your eggs in one basket. While we take extensive precautions to keep all our generation facilities online, events beyond our control do occur. In August 2011, a 5.8-magnitude earthquake took both reactor units at our North Anna Power Station in Virginia offline. While no one was hurt and no radioactive material was released, rigorous evaluation and inspection were required before the reactors could be brought back into service more than two months later. Embargoes, price shocks, weather, and other circumstances also can interfere with other kinds of generation. A diverse mix of energy sources creates a buffer between those factors and the millions of families and businesses that rely on Dominion Energy for uninterrupted power.
Grid Reliability Projects
All the generation capacity in the world is of no use without sufficient transmission and distribution infrastructure to deliver power to customers when they need it. Dominion Energy takes care to ensure the infrastructure is up to the job. In 2019, we added 13 new miles of transmission line and rebuilt another 166 miles. We energized the Surry-Skiffes Creek 500 kilovolt transmission line project, a 7.7-mile project in Virginia that ensures reliable electricity service to 600,000 customers and made possible the environmentally beneficial closure of two coal-fired generation units at Yorktown Power Station in Virginia.
We continued working to strengthen and upgrade the 410-mile, 500-kV loop that serves as the backbone of our Virginia service area by replacing towers and running new electrical lines. As of year-end 2019, we had completed 249 miles of the loop with another 82 miles under construction. (As of June 15, 2020, 18 miles of the 82 under construction had been completed.)
In 2019, we spent $558 million on electric transmission and distribution maintenance, including $76 million specifically for distribution reliability investments.
We continue to improve the grid in South Carolina as well. From the beginning of 2011 through the end of 2022, Dominion Energy South Carolina will have newly constructed or rebuilt approximately 35 percent of its electric transmission system.
Dominion Energy Virginia revised its Grid Transformation Plan (GT Plan) in 2019. The comprehensive, 10-year plan was designed to transform the way we provide service to our customers as part of our company’s “Smart Energy” initiative. Strengthened by extensive input from customers, collaboration with stakeholders, and a thorough third-party cost-benefit analysis, the updated plan was filed with the State Corporation Commission of Virginia in September 2019 and focused on six primary components, many of which are foundational to a transformed grid:
- smart meters;
- a new customer-information platform;
- grid improvements, which include grid technologies and grid hardening;
- telecommunications infrastructure;
- physical and cybersecurity; and
- an electric vehicle Smart Charging Infrastructure Pilot Program.
In March 2020, the Commission issued its Final Order on the most recent filing for the company’s proposed GT Plan. We are pleased that it approved several elements of the GT Plan, including:
- a new customer information platform;
- targeted grid hardening, voltage island, and corridor improvements;
- an electric vehicle Smart Charging Infrastructure Pilot Program;
- stakeholder engagement and customer education;
- cybersecurity protections;
- hosting capacity analysis; and
- a microgrid demonstration project.
These investments will allow us to give our customers more options to access their energy usage information and bills while we provide even more dependable service.
Although the Final Order denied approval of smart-meter technology, grid technologies, and other components, the company believes strongly in the benefits these investments will bring our customers. Consequently, we will continue to pursue a pathway for these elements in the future.
Using a data-driven process, we continually analyze the performance of distribution tap lines — the overhead wires that go into neighborhoods — over a 10-year period. Those most prone to outages are considered for placement underground. Tap lines typically sustain the most damage during storms and require the highest number of repairs. In addition to reducing outages for those served by the lines converted to underground, our Strategic Underground Program has a broader advantage: It allows repair crews to move to other outage locations more quickly, thereby restoring power sooner for everyone.
In 2019, we invested $143 million in strategic undergrounding, and held 47 community meetings to discuss the program. We placed 683 tap lines totaling 247 miles underground, bringing the program total for all years to 3,708 tap lines and 1,301 miles. Thanks to these efforts, we have removed 1,859 annual outage events from our system (as of the end of 2019) and when the program is completed, we expect these measures to reduce the time it takes to restore service for all customers after severe storms by as much as 50 percent.
Storm Preparation and Training
These highlights don’t cover the many other efforts we make to sustain and improve power delivery — from replacing transformers and adding utility poles to installing new switches and sensors.
We also place a heavy emphasis on storm preparation and training. Our obligation to serve all customers requires that we plan for severe weather. That starts long before the first cloud appears on the horizon, with annual training for everyone who will work on the front lines when a major event happens. The training takes place through both online learning modules and hands-on, face-to-face instruction, and covers topics such as damage-assessment patrolling, coordination with first responders, proper procedures to ensure safety around downed power lines, and the different responsibilities for each role in the company's storm restoration process.
We practice and prepare all year long for severe weather. Among other things, we take part in the Southeastern Electric Exchange Mutual Aid Conference and exercises held by state departments of emergency management and the Edison Electric Institute.
When a major storm approaches, we stage crews and equipment in the field so they can begin work as quickly as possible. In Virginia and North Carolina, our regional operational centers coordinate with the system-wide storm center in Richmond, Va., and coordinate with local emergency management and jurisdictional authorities. We alert the public about the storm’s potential and offer advice on how customers can be prepared. Dominion Energy South Carolina has similar protocols, including an Emergency Operations Center that utilizes an Incident Command System (ICS). DESC also works closely with the South Carolina Emergency Management Division (SCEMD) and the Office of Regulatory Staff via its Emergency Support Function 12 desk (ESF-12).
And when severe weather hits, we follow careful and detailed emergency restoration plans. These begin with an initial damage assessment within the first few hours, while simultaneously taking swift action to restore power to critical public-safety and health facilities first, and then residential and commercial customers.
These efforts have proved successful again and again. After Hurricane Dorian caused more than 172,000 outages in Dominion Energy’s eastern Virginia and North Carolina service area in September 2019, Dominion Energy crews restored service to 100 percent of customers within three days after the storm — dedicating a collective 53,400 hours to the recovery effort. In South Carolina, Dominion Energy restored power to 80 percent of customers within the first 24 hours after the storm. By the evening of September 8, two days after the storm, DESC had restored power to 100 percent of customers. In January 2020, the Edison Electric Institute gave our company the Emergency Recovery Award, citing the company’s high standards and commitment to customers. This is the twelfth time Dominion Energy has received the award.
As part of planning for outage restoration, our Emergency Preparedness Center has an outage-prediction model that uses machine learning to project the number of customer outages and work orders based on weather patterns and historical outage data.
Resilience and Physical Security
For years, Dominion Energy has used the National Electric Safety Council’s (NESC) combined ice and wind loading criteria as the basis for design standards for typical distribution facilities. In order to harden the system even further against extreme weather, in 2019 the company began designing all future construction to meet the stronger of the NESC’s heavy loading criteria for combined ice and wind, or the extreme-winds criteria of the American Society of Civil Engineers. This will lead to a stronger, more resilient distribution grid by dictating larger poles and shorter spans between them, resulting in less damage and faster restoration during severe weather events. Additional improvements to standards include establishing a minimum pole class across the system, requiring deeper pole setting or select backfill in areas with poor soil, expanding the use of fiberglass cross-arms, and using upgraded insulators.
In 2019, we installed flood seals around many of our pad-mounted transformers. The seals prevent corrosion, which could lead to component failure. We are also further hardening electric distribution substations commensurate with the risks associated with disruptions to reliable operations to customers served by the substation. Additionally, the company maintains a concerted effort to harden boundaries and implement sophisticated asset monitoring around the perimeter of our substations.
Electric reliability is measured by the System Average Interruption Duration Index (SAIDI), which tracks the average number of minutes a customer is without service, excluding major events such as storms. In 2019, the typical Dominion Energy Virginia customer was without power for approximately two and a half hours over the course of the year outside of major events.
In South Carolina in 2019, Dominion Energy achieved an excellent SAIDI score of 77.89, a historic record for the business segment.