The History of the Union Gas Facilities
Anchored by the Dawn Hub

Pre-Historic Beginnings

During the Middle Silurian Age, 425 million years ago, the Michigan Basin, a geological feature that underlies most of the state of Michigan and south-western Ontario, was covered by a warm shallow and relatively flat sea that dipped in the middle. Coral reefs grew in belts around the perimeter of the basin. Over time, these reefs were buried by sediment, converted by pressure and time to limestone. These porous limestone fossilized coral reefs are encased with a hard cap rock of anhydrite and now sit 450m to 670m (1,500 to 2,200 ft.) underground. Over millions of years natural gas formed and was captured in these formations. Discovered in the latter part of the 19th century, natural gas was subsequently produced from these areas.

Locally Produced Natural Gas and Subsequent Storage Use

These pools were drilled and the gas that was captured in them was removed and consumed in the local areas over the first half of the 20th century. During the 1940’s, with the increased depletion rate of locally produced natural gas reaching a critical point, Dr. C. S. Evans, Union Gas' first full-time geologist and R. L. Bevan, Chief Engineer, proposed that these underground reefs could be used once again, now to store other new natural gas supplies, to be used during peak cold weather conditions. In September of 1942, Union Gas experimented by feeding gas for the first time into these depleted pools in Dawn Township. This was an important milestone in Union Gas' history as it enabled the Company to grow from a small operation into the diverse company it is today.

Expanding Pipeline System Infrastructure to Tap into New Supply Sources

In November, 1944 Union Gas negotiated its first 20 year supply contract with Panhandle Eastern Pipe Line Company (PEPL), to supply up to 5.5 billion cubic feet of natural gas per year. Two years later, a new pipeline was buried deep beneath the Detroit River, connecting the Union Gas storage facilities and those of PEPL. Delivery began in late 1947 and would occur annually between April 1 and November 1, when the demand for gas in the United States was low. To enable this gas to more effectively feed the new storage facilities at Dawn, Union Gas installed a 16” diameter pipeline between Windsor and Dawn in 1951 and added an additional 20” diameter pipeline several years later.

In December 1957, the 229 km (142 mile) 26” diameter Trafalgar Line was completed between Dawn and the Trafalgar Compressor Station (now known as Parkway) just west of Toronto. This new line provided a connection to TransCanada Pipelines (TCPL) and Enbridge Gas Distribution, which serves the city of Toronto. In these early days, Union Gas lent gas to TCPL for the purpose of market build up until the Western Canadian Gas was available through TCPL’s northern pipeline route.

The first deliveries of Western Canadian Gas were received at Parkway by Union Gas for use by our Customers and to fill the storage reservoirs at Dawn on October 27, 1959.

The Dawn to Parkway System has continued to expand since its original construction. The original 26” line has been entirely looped with 34”and 42” pipelines and recent expansions contribute to the completion of the 4^th loop, a 48” pipeline. Two compressor stations have been added to the pipeline – Lobo and Bright – and along with the compressor station at Parkway, they play a critical role in the transport of natural gas along the Dawn to Parkway system. The peak day for volumes of gas leaving Dawn has increased dramatically over the years and currently sits at approximately 6.7 PJs (6.3 Bcf) per day.

On November 1, 1967, TCPL commenced deliveries to Union Gas at Dawn via a new pipeline constructed through the United States – Great Lakes Pipeline. Union Gas completed the St. Clair river crossing connecting to Michigan Consolidated Gas Company in 1989 to allow for access to more diversified supply sources. During the early 2000’s connections to both Bluewater Gas Storage (again connecting to Michigan based supply sources) and the Vector Pipeline Limited Partnership (anchored in Chicago) have allowed for more supply sources to be accessed and connected to the Dawn Hub. The multiple direct and indirect pipelines that have access to the Dawn Hub permit Ontario to benefit from gas supplies sourced from major basins across Canada and the United States, including Western Canada Sedimentary Basin, Rockies, and the Gulf of Mexico. Currently the capacity of pipelines feeding into the Dawn Hub has increased to almost 4.8 PJs (4.5 Bcf) per day that can be used by our Customers, injected into storage or moved to markets further downstream.

The Growth of Gas Storage and the Dawn Hub

From the humble prehistoric beginnings, the Dawn Hub and the integrated physical storage infrastructure has grown dramatically. The old pinnacle reefs that make up the storage pools range in area from 25 to 200 hectares (60 to 500 acres) and can be from 55 to 120 metres (180 to 400 feet) thick. From the initial storage wells drilled in the early 1940’s, Union Gas has added many new wells, new compressors and one of the world’s largest dehydration facilities (to remove any water trapped with the natural gas in the pools) to allow for ever increasing amounts of gas to go into and out of storage. Today the Dawn Hub is comprised of 22 storage pools, 450,000 HP of compression and an intricate system of interconnecting pipelines. The storage capacity of Union Gas' Dawn Hub is over 166 PJs (155 Bcf) of space with the ability to inject or withdraw just under 3 PJs (2.8 Bcf) when operating at peak capacity. Union Gas continues to explore and develop new storage pools in and around the Dawn Hub to continues to expand the options, flexibility and reliability the marketplace demands.

Go to Dawn - A World Class Facility

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