Connecting a gas line from the North Slope

There has been much talk of building a pipeline that could deliver natural gas from the North Slope to Southcentral Alaska, to alleviate potential gas shortages in the Southcentral region. But where exactly would such a pipeline connect into the Cook Inlet gas infrastructure?

During a talk at the Anchorage Mayor’s Energy Task Force meeting on May 1 John Lau, director of engineering for Enstar Natural Gas Co., said that a North Slope line could easily tie into Enstar’s gas transmission line that runs from the west side of Cook Inlet north into the Matanuska-Susitna Valley. The Enstar line was installed in 1984 to bring west side gas to the city of Anchorage. But with major declines in production since then from gas fields on the west side of the inlet, the line is substantially under used. Enstar could in fact bring the whole of Anchorage’s gas supply through that line, should there be a source of gas to fill the line, Lau said.

And gas storage, such as that now operated by Cook Inlet Natural Gas Storage Alaska, or CINGSA, would become of prime importance in maximizing the efficiency of gas shipments though a North Slope line, Lau said. Rather than needing a throughput capacity sufficient to meet peak winter demand, the existence of gas storage facilities would enable the North Slope line to meet Southcentral’s needs by just delivering the annual average daily demand, a much smaller volume than the maximum demand. While delivering gas at this constant, average rate, excess gas during periods of low summer demand would be diverted into storage for use during the winter, when demand might exceed the capacity allocated on the North Slope line for Southcentral use.

—Alan Bailey