Enbridge natural gas storage

Steckman Ridge Storage Facility, Bedford County, Pennsylvania

Enbridge owns or operates eight natural • A depleted reservoir storage facility gas storage facilities in the United States usually consists of numerous wells, a Typical Cemented Casing Program (U.S.) and 36 natural gas storage fields at system of pipelines that link the Salt Caverns Wellhead the Dawn Hub storage facility in Ontario, transmission lines to the storage field or Canada, with a net working storage of about pools, and compressor station(s) to boost 438 billion cubic feet (Bcf). the pressure of the natural gas so it is able Ground Surface to flow between the field or pools and the Conductor Casing Enbridge engineers, builds, operates, ~100ft and maintains its storage facilities to transmission pipelines. meet—or exceed—all federal, state and Salt caverns Deepest Drinking Water Zone provincial regulations. Surface Casing All Casings Cemeted • Salt caverns, constructed in naturally to Surfact (typical) These storage facilities provide natural occurring salt domes or salt beds, create ~900ft gas producers and consumers with strong and environmentally sound storage Caprock First Intermediate working capacity and the flexibility of for natural gas. Salt is impermeable and Casing ~2,500ft interconnections with major pipelines to self-sealing so stored natural gas does reach a variety of markets. not escape. Salt • Water is used to dissolve and extract salt Second Intermediate Types of storage Casing ~3,200ft when creating a salt cavern, which can Production Casing ~3,700ft Enbridge’s underground natural gas storage extend nearly a mile underground. Salt Un-cased Borehole Bottom of Wellbore facilities are classified as either salt caverns cavern storage also includes fresh water ~5,300ft or depleted reservoirs. supply wells and handling facilities, brine Depleted reservoirs handling facilities, and disposal wells, and a compressor station to provide the • At depleted reservoirs, natural gas is necessary pressure to move natural gas injected back into underground fields or into and out of the caverns. pools that once produced natural gas. The geological characteristics of the underground porous rock formations in the reservoirs allow natural gas to be stored safely and accessed efficiently.

Approximate amount of all natural Approximate number of active gas consumed during the five-month storage facilities in 30 states winter heating season each year is 400 20% supplied by underground storage Integrity management five years. In July 2015 and September Federal 2015, respectively, API published • The Federal Energy Regulatory Commission Enbridge’s integrity management program recommended practices 1170 (“Design (FERC) regulates storage projects includes regular inspections of storage wells and Operation of Solution-Mined Salt connected to interstate pipeline systems. to identify integrity issues or metal loss. Caverns Used for Natural Gas Storage”) FERC is responsible for conducting Inspections include three primary integrity and 1171 (“Functional Integrity of Natural an environmental review of proposed components: the wellhead, wellbore and Gas Storage in Depleted Hydrocarbon projects, and authorzing the construction cavern or reservoir (or container). Reservoirs and Aquifer Reservoirs”). or expansion of storage facilities and the • At each storage facility, Enbridge also • Enbridge is working diligently to complete terms and conditions of service (i.e. open conducts regular leak surveys, including enhancements in order to meet these access) and the rates charged by foot and aerial patrols, and regularly recommended practices within the these providers. upgrades and enhances facilities to ensure required timeframe. • The Pipeline and Hazardous Materials safe operations. Safety Administration (PHMSA) is authorized to regulate the safety of natural • Enbridge’s storage wells are engineered so Regulatory oversight gas transportation and storage. that inline inspection tools, or smart pigs, State/provincial The Occupational Safety and Health can inspect the entire vertical depth of • Currently, each of the states and provinces Administration (OSHA) has regulatory the well casing (also known as production we operate in has primary oversight of our oversight of the operation and maintenance casing or final cemented casing) to detect storage facilities, and we work with each of above-ground components and any blockage, dents, or corrosion, and verify agency to ensure our facilities meet or equipment associated with underground the thickness of the casing. exceed their requirements. storage facilities. • Safety valves are installed at the wellheads CANADA of all Enbridge’s natural gas storage facilities. At our salt caverns, these can be UNITED STATES OF AMERICA closed remotely by Enbridge’s Gas Control Dawn Leidy center. At our reservoirs, these valves can Oakford be closed either manually or remotely by Accident Steckman Enbridge’s Gas Control center. Ridge

• In 2011, Enbridge began working with Saltville the American Petroleum Institute (API), Interstate Natural Gas Association of America (INGAA), American Gas Salt Cavern Association (AGA), and other stakeholders Natural Gas to develop more clarity around storage Storage Facility integrity management practices. Depleted Reservoir Moss Blu
Bobcat Natural Gas • Enbridge has been instituting these Egan Storage Facility

practices into its operations for the past MEXICO

Enbridge’s storage facilities and regulators

Facility Location Net Working Capacity Type Regulators

Accident Storage Accident, Maryland 18.3 Bcf Depleted Reservoir Maryland Department of the Environment

Louisiana Department of Natural Resources Bobcat Gas Storage St. Landry Parish, Louisiana 28.4 Bcf Salt Cavern (by authority of the EPA)

Ontario Energy Board Ontario Dawn Storage* Sarnia, Ontario, Canada 280 Bcf Depleted Reservoir Ministry of Natural Resources and Forestry

Louisiana Department of Natural Resources Egan Acadia Parish, Louisiana 20.6 Bcf Salt Cavern (by authority of the EPA)

Leidy** Leidy, Pennsylvania 15.3 Bcf Depleted Reservoir Pennsylvania Bureau of Oil and Gas Management

Texas Railroad Commission Moss Bluff Liberty County, Texas 21 Bcf Salt Cavern (by authority of the EPA)

Oakford** Oakford, Pennsylvania 40.7 Bcf Depleted Reservoir Pennsylvania Bureau of Oil and Gas Management

EPA; Virginia Department of Mines, Minerals Saltville Saltville, Virginia 5.0 Bcf Salt Cavern and Energy

Steckman Ridge Bedford Country, Pennsylvania 6.0 Bcf Depleted Reservoir Pennsylvania Bureau of Oil and Gas Management

* Capacity total includes nearby St. Clair Pool and Sarnia Airport Pool depleted reservoir storage assets ** Operated by Dominion Transmission

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