Alan Bailey, Petroleum News

The Interior Gas Utility, or IGU, the gas utility owned by Fairbanks North Star Borough, has been planning its gas distribution pipeline network for the Fairbanks area and has determined that it will need a gas transmission line around the perimeter of the city, David Prusak, the project manager for IGU’s distribution network construction, told the Alaska Industrial Development and Export Authority board on Sept. 25. IGU is planning a six-phase build out of its network, extending the network around the city, with each of the phases taking a year to complete. Gas feedstock for the system, obtained in the form of liquefied natural gas, would enter the system at North Pole, to the southeast of the city, and move counterclockwise around the city.

The IGU development is one component of the Interior Energy Project, a project to bring affordable natural gas to Fairbanks by trucking LNG from the North Slope. AIDEA is providing funding assistance for the project.

Hydraulic modeling

With assistance from Enstar Natural Gas Co., IGU has been modeling the hydraulics of gas flow around the planned system, in part to ensure redundancy in gas supply routing as a means of underpinning supply reliability. But the modeling found that, to maintain that flow around the entire city, the gas pressure must be raised above the level appropriate to gas distribution to consumers, Prusak said. The solution appears to be to run a transmission line around the city’s perimeter, to feed gas into the distribution system at various points, he explained.

Gas utility Fairbanks Natural Gas distributes gas in the central part of Fairbanks, with IGU’s service area encompassing the city’s perimeter. But there is no cost advantage in transmitting gas radially out from the center to supply IGU’s network, Prusak said. Besides, the location of IGU’s main storage and feed point at North Pole would be convenient if in the future IGU’s services were to be extended into the military base at Fort Wainwright, to the east of Fairbanks, he explained.