By nature, natural Gas pipeline systems are transient. Supplies, demands and operations change during the day. A pipeline system is always in a state of pack or draft and this phenomenon can be used to reduce facilities. Average daily flow conditions rather than peak hourly flow rates are designed for. Estimating how customer demands change over the day is needed to create demand profiles. Many types of customer gas usage patterns exist and are related to heat and non heat dependent factors. Customers include residential, commercial businesses, greenhouse, agricultural drying, industrial process and power generation. These differing customer types all use gas in different ways during the day. This paper will explore the shape of demand profiles for different customers; show the drivers behind the different shapes and their respective impacts on the pipeline system. Demands on a system are a combination of all the customer types and their corresponding profiles. Some of Union Gas Limited's (Union's) 20 demand profiles for the Dawn to Parkway Transmission system are shown. These profiles vary over the years. Depending on the day of the week, holidays and interruptions, gas usage will change. The paper will discuss data collection and considerations on when to exclude data. Profiles "flatten" during cold weather. As the temperature gets lower and lower, heating systems reach their peak capacity, staying on for longer periods of time. A study Union completed shows, as the average daily temperature decreases; demand profiles change shape including a lower morning peak. Union's philosophy regarding the creation of demand profiles has changed from a technique called "Cluster Analysis" to a technique using several years of data averaged together. The paper will briefly discuss the old method, some pitfalls and why Union has transitioned to the new method.


Union Gas Limited is a major Canadian natural gas storage, transmission and distribution company based in Ontario. This year, Union celebrates its 100 year anniversary. Union Gas's growing storage and transmission business offers premium services at the Dawn Hub, the largest underground storage facility in Canada and among the largest in North America.


Union Gas' distribution system serves 1.3 million customers in 400 communities across northern, southwestern and eastern Ontario. Distribution main pipelines 36,238 km (22,517 mi) Distribution service pipelines 23,944 km (14,878 mi) 30% Specified Minimum Yield Strength (SMYS) pipelines 4,728 km (2,938 mi)


The Dawn Hub offers customers such as power generators, distribution and pipeline companies and energy marketers an important link in the movement of natural gas from Western Canadian and U.S. supply basins to markets in central Canada, the Great Lakes region and the northeast U.S. Transportation Union's Dawn to Parkway transmission system consists of four parallel pipelines ranging from 660 to 1220 mm or 26 to 48 in diameter and three mainline compressor plants. In addition to its distribution customers, Union transports gas for TransCanada, Enbridge Consumers, Gaz Metropolitan, Keyspan, Brooklyn Union, Con Ed, and many other local distribution companies in North Eastern US.

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