RCA allows CIGGS bidirectional flow

Commission grants temporary approval so that essential pipeline system modifications can be made prior to the onset of winter

Alan Bailey

Petroleum News

The Regulatory Commission of Alaska has granted temporary authority to Marathon Oil Co. to make some modifications to the Kenai Nikiski pipeline and the Cook Inlet Gas Gathering System, or CIGGS, to enable the flow of gas east to west through CIGGS, under Cook Inlet. Currently, gas can only flow west to east through the pipeline system.

At the end of August Marathon asked RCA for approval of an agreement with power utility Chugach Electric Association to enable bidirectional gas flow through CIGGS. Chugach, concerned about winter gas supplies for its Beluga power station on the west side of the Cook Inlet, as production from the Beluga gas field adjacent the power plant declines, wants to be able to obtain gas direct from the Kenai Peninsula through CIGGS. Currently if Chugach buys gas on the peninsula it has to swap that gas for other gas, delivered by Enstar Natural Gas Co. on the west side of the inlet. But Enstar, also pressed to find adequate gas to meet peak winter demand, has told Chugach that it cannot guarantee to supply the volumes of gas that Chugach may need.

To assure adequate gas supplies for the Beluga power station during the coming winter, Marathon told RCA that the pipeline system modifications required for CIGGS bidirectional flow needed to be started on Oct. 1, to complete the work before the onset of winter. RCA responded by issuing its temporary authorizations on Sept. 29. The modifications essentially involve installing a rented gas compressor in the Kenai Nikiski line at the junction with CIGGS; the removal from CIGGS of some check valves that currently prevent east to west flow; and the bypassing of some CIGGS equipment at East Foreland. The metering system at the junction with the Kenai Nikiski will also require modifications for bidirectional flow.

The compressor near the pipeline junction will enable the pressure in the Kenai Nikiski line to be raised, an essential requirement for pushing gas east to west through CIGGS.

RCA said that the temporary authority it has granted only applies to the pipeline system modifications, and does not apply to other components of Marathon’s CIGGS bidirectional flow requests, including pipeline tariff changes. A final decision in the commission’s review of Marathon’s CIGGS bidirectional flow application could result in denial of the application, including a denial of the request for the modifications that the commission has temporarily approved, the commission said.