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We use a wide array of diagnostic tools, preventive maintenance programs, and oversight techniques to identify and mitigate potential issues long before they can become a problem.
N.b.: In July 2020, we announced the pending sale of substantially all of our gas transmission and storage assets to Berkshire Hathaway Energy. Some smaller gas storage will remain in Dominion Energy’s gas distribution portfolio.
Dominion Energy’s more than 2,300 storage wells and reservoirs are designed to withstand fluctuating pressures associated with the injection and withdrawal of natural gas, season after season. Through regular inspections, we monitor the condition of the lining, or casing, that contains the storage pressure within the wellbores. Company wells contain up to three concentric linings. On many, the innermost casing is surrounded with cement from deep in the wellbore to the surface of the ground, to provide additional leak prevention.
Dominion Energy has been using electronic logging tools to inspect our storage wells since 1973, years before that technique was required by the Pipeline and Hazardous Materials Safety Administration (PHMSA). The process involves lowering a high-resolution electronic device into the well to take electromagnetic readings over its entire length. The readings provide important information regarding the condition of the well — information that is then used to determine what, if any, remedial work will be performed.
We perform well-casing integrity inspections for internal and external corrosion. Through other regular inspections we verify well status and pressure, and look for signs of atmospheric corrosion, venting gas, or leaks. These inspections are complemented by remote monitoring and monitoring of third-party drilling activities in and around our storage pools. And in the unlikely event of a major leak, the company has site-specific emergency plans for each storage field.
Our Integrity Management process meets or exceeds the requirements of PHMSA rules regarding underground storage. The formal risk management strategy includes an initial evaluation of risk based on threats and consequences of potential events. Any significant risks are then addressed through the application of specific preventive and mitigation measures. The process includes feedback and validation measures for continual improvement. A capital budget is established each year for necessary repairs and improvements, such as replacing wellheads and casings, to reduce potential risk and keep the system operating efficiently.
In 2018, PHMSA began its first audits of storage facilities in the United States. Its audits of Dominion Energy’s program, and several of its storage facilities, produced no significant findings. In 2019, PHMSA audited three of our storage facilities and performed one program audit. Three of the audits concluded with no significant findings; Dominion Energy Transmission, Inc. received a Warning Letter related to monitoring of annular vents on storage wells in the Fink Kennedy Lost Creek Storage field. DETI implemented a follow-up plan to address this issue.
The company’s leadership fosters a culture of integrity management. Our objective is to align with the spirit of the regulation, beyond basic compliance with the code. Dominion Energy supports pipeline integrity activities through written Integrity Management Programs, objective analysis and evaluation, and making performance improvements as necessary to manage risks. We created a Transmission Integrity Management Program (TIMP) and a Distribution Integrity Management Program (DIMP) that meet or exceed PHMSA integrity management regulations.
Our TIMP addresses the following components:
- High-consequence areas;
- Threat identification and risk assessment;
- A baseline assessment plan;
- Remediation and prevention;
- Performance and quality assurance;
- Change management; and
The company inspects and assesses its transmission pipelines in numerous ways — including patrols and around-the-clock monitoring from Gas Control command centers. In addition to regular aerial observation and foot patrols, pipelines also are inspected from the inside with in-line tools that are often called “smart pigs.” These devices use computerized sensors capable of detecting and reporting anomalies such as dents and corrosion, enabling us to make appropriate repairs to ensure the integrity of the pipe. They are introduced at specialized launch sites, and move through the pipeline to downstream receiving locations. The data collected by these sensors is then analyzed to determine whether pipeline segments need replacement or repair. Dominion Energy uses smart pigs on more than half of its transmission and storage system — well beyond regulatory requirements.
Dominion Energy continuously monitors the flow of gas using remote sensors, which are placed along the entire length of a pipeline. Remote-controlled safety shutoff valves allow Gas Control operators to stop the flow of gas immediately and isolate individual sections of pipeline if necessary.
To prevent external corrosion, the company operates cathodic protection systems on our underground steel assets. In addition to annual monitoring at key locations, we perform detailed corrosion surveys for an average of 1,000 miles of transmission pipeline each year to confirm that these protection systems are functioning effectively.
We prevent internal corrosion through vigilant monitoring of constituents in the gas stream, evaluating potential impact of impurities, and applying targeted preventive and mitigating measures. The company also examines the internal and external surfaces of our assets whenever operating and maintenance activities provide such opportunities, to validate the effectiveness of our programs.
Dominion Energy Transmission, Inc. (DETI) has had multi-year projects to replace bare steel transmission pipe and to install remote-controlled valves (RCVs). As of the end of 2019, DETI replaced 41.5 miles of bare steel transmission pipe. At the completion of 2019, Dominion Energy has installed over 250 RCVs through the course of this program to reduce response times for our Distribution and Transmission companies. We also are using alternative methods to move beyond traditional inline inspection techniques to inspect low flow/low pressure pipelines to increase the number of pipelines it can assess, and we are deploying inline inspection tools to assess our seamed pipelines.
Dominion Energy’s Distribution Integrity Management Program (DIMP) addresses the following elements:
- Knowledge of the distribution system;
- Threat identification;
- Evaluation and ranking of risk;
- Identification and implementation of measures to address risks;
- Measures of performance, monitoring of results, and evaluating effectiveness;
- Periodic evaluation and improvement;
- Reporting results; and
- Document and record retention.
The company maintains a number of other programs to ensure distribution pipeline safety as well.
- An enhanced excavation-monitoring program for high-risk excavation sites;
- A damage investigation program to conduct root-cause analysis of damage to pipes;
- An excavator communications and training program to inform the public and excavators about the importance of safe excavation practices;
- An enhanced leak survey program to accelerate leak surveys on higher-pressure distribution lines that are located outside of business districts; and
- A cross-bore verification program to investigate older pipeline projects that were directionally drilled prior to preventive procedures that are in place now.
Additional safety assessments for transmission and storage pipelines occur on both a cyclic and as-needed basis. This redundant system of vigilant monitoring enables Dominion Energy to detect and fix any problems in its system long before they present a hazard. Because of these efforts, the company has made substantial progress not only in safety but in other areas as well. For example, from 2018 to 2019, our gas operations in Ohio and West Virginia saw a 56 percent decrease in reportable environmental events.
Practice Makes Perfect
Larry Gentzyel, a senior safety specialist in Gas Transmission & Storage, noted with alarm a series of near misses when workers siphoned gas lines. He attributed this to a lack of hands-on training: People retain information better when they can engage more of their senses while absorbing it.
So Larry developed a hands-on training device to train proper siphoning techniques. Not only that, he made the device portable, so it could be taken to field locations.
While he originally designed it for siphoning instruction, Larry realized the device could be modified for use in teaching other operations such as blowing down, loading, purging, bonding, and more. His invention won him a Peer Choice Award in the company’s Chairman’s Excellence Awards — a yearly competition recognizing employee ingenuity and prudent risk-taking — as well as the overall Chairman’s Excellence Award for 2019.
Pipeline Safety Management System
In addition to the foregoing, Dominion Energy also has implemented a Pipeline Safety Management System (PSMS). This is a voluntary program modeled on similar ones in other industries such as aviation and chemical manufacturing. The PSMS program takes a systematic and measurement-based approach to pipeline safety both across business units and within them, from top executives to field workers. The aim is to identify areas for improvement and share that information widely. This PSMS program is a never-ending journey for continuous safety improvement.
Several years ago, Dominion Energy formed a steering committee to develop and implement the PSMS program and put it into place across all of Dominion Energy’s natural gas businesses. In 2019, a working group focused on moving forward the first three of 10 PSMS program elements: leadership and management commitment, incident investigation and lessons learned, and emergency preparedness and response. These elements have been tied to the company’s annual incentive plan.
It is critical that our customers, contractors, and employees know how to take safety precautions around gas infrastructure. Given the widespread nature of our natural gas grid, the general public also plays a key part. Over the past 20 years, third–party damage has been the primary cause of incidents on natural gas pipelines.
Dominion Energy conducts public awareness programs to educate landowners near company facilities to reduce the likelihood of dig-ins or other harm that can cause a release of methane to the atmosphere. The company has long supported laws requiring use of the 811 “Know what’s below. Call before you dig” one-call system. Anyone planning to do work that disturbs the soil beneath streets, sidewalks, yards, farms, or other property is required to call the designated number. Utilities, authorities, and others mark their underground facilities before work begins. Excavators can call a state one-call system or the national number: 811. These one-call programs are a valuable component to protect our system and to ensure safe operations.
Thanks in part to extensive safety measures, natural gas emergencies occur very rarely. Those that do often result from external factors, such as third-party excavations carried out near underground pipelines without adequate precautions. Because the potential for emergencies still exists, our company has developed rigorous and comprehensive programs and policies to mitigate them.
Dominion Energy maintains and values positive, long-term relationships with fire departments, police departments, and sheriffs’ offices. We conduct annual public-liaison meetings with emergency-response agencies. In 2019, for example, Dominion Energy Transmission, Inc. hosted a gas pipeline safety seminar for pipeline operators, supervisors, and other industry professionals in Bridgeport, West Virginia. The all-day event was free for the roughly 100 attendees.
We have installed remotely operated valves that can be closed when a pipeline leak or rupture occurs on a transmission pipeline. Compressor stations have similar emergency shutdown systems activated through manual controls. Those systems are tested at least annually.
We have developed response plans for a variety of contingencies that could affect pipelines, compressor stations, and storage wells. When there is an emergency call related to our distribution infrastructure, our personnel are onsite within one hour at least 98 percent of the time.
Damage Prevention Efforts
Because third-party damage represents the primary threat to the safety and integrity of our natural gas pipelines, Dominion Energy has taken significant steps to strengthen its damage-prevention efforts, particularly in the past year. In October 2019, we formed a Damage Prevention Department specifically to address excavator dig-in damage to our gas facilities. We are working on the following initiatives to make Dominion Energy an industry leader and model company for damage prevention:
- Risk Modeling Software – This software analyzes the 811 locate ticket data to determine which dig sites represent a high risk so that a representative can intervene.
- 811 Near Ticket Application – This application communicates with the state’s One Call ticket system to identify dig sites that do not have a valid locate ticket. Our representatives will intervene in those identified excavations so that work can be stopped until all utilities are marked.
- Gold Shovel Standard – Dominion Energy and its new construction contractors have committed to adhering to this industry damage prevention certification process, which requires the reporting of all damages to a centralized data center.
- Homeowner 811 Gas Ambassador – This yard-sign program encourages homeowners who have damaged our gas facilities after failing to call their state’s 811 One Call Center to allow public-service message signs to be placed on their property to educate their neighbors.
- Damage Prevention Staffing Study – This study looks at the organizational structure of American Gas Association peer companies that have successful damage prevention programs.
These efforts have produced a strong safety record that has received industry recognition. In 2019, Dominion Energy received the American Gas Association Safety Achievement Award for Employee Safety (earned by Dominion Energy West Virginia; Dominion Energy South Carolina, Inc.; Dominion Energy Ohio; Dominion Energy Carolina Gas Transmission, LLC; Dominion Energy Questar Pipeline, LLC; and Dominion Energy Transmission, Inc.); the AGA’s Industry Leader in Accident Prevention Award (earned by Dominion Energy Ohio and Dominion Energy Utah-Wyoming-Idaho); and the AGA’s Safety Achievement Award for Vehicular Safety (earned by Dominion Energy Carolina Gas Transmission, LLC).