Cook inlet natural gas storage Alaska: bringing CINGSA on-line for Railbelt utilities.

• Author: Storm, Gene
• Position: CONSTRUCTION

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The specter of natural gas demands exceeding supply during South-central Alaska's coldest, darkest months has been averted in the short term with the construction of the state's first commercial storage facility in Kenai. The Cook Inlet Natural Gas Storage Alaska (CINGSA) facility began pumping gas into an underground storage reservoir with a capacity of 11 billion cubic feet (Bcf) on April 1 of this year. CINGSA will release gas to buffer the supply from Cook Inlet producers when the heating and electrical generation demands peak in winter.

Construction began on the facility located on the eastern side of Cook Inlet within the City of Kenai in March of last year following the issuance of a Certificate of Necessity and Public Convenience from the Regulatory Commission of Alaska on Jan. 31, 2011. CINGSA also obtained an additional 56 permits from more than a dozen local, state and federal agencies for the $161.4 million project, and worked with a host of surface and sub-surface mineral rights owners.

Early work on the project started in May of 2009 when SEMCO Energy, ENSTAR's parent company headquartered in Port Huron, Michigan, approached TransCanada Corp. of Calgary, Alberta, to develop preliminary engineering and design documents. Initially, TransCanada was going to own the facility, but SEMCO bought out the Canadian company's interest. CINGSA is part of ENSTAR's Alaska operations as a natural gas supplier to residential customers and electrical utilities.

The purchase brought to Alaska the expertise of two chemical engineers who had been involved in the preliminary work at TransCanada. Here, they continued their work on the facility as project managers for CINGSA. Richard Gentges and Ed Scarpace brought more than 60 years of combined experience on the design and construction of underground natural gas storage fields to the project in Kenai. They have worked together on 10 similar projects over the last 30 years. On this project, Scarpace managed construction of the facility's surface elements while Gentges oversaw development of the reservoir and storage wells.

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Critical Factors

Pinpointing the proper location for CINGSA was critical. Factors considered were the size of the reservoir, proximity to existing infrastructure, environmental impact, and overall estimated cost. "We looked at 50 different sites initially, cutting it to the top 10 and then the top three before making the selection," Gentges says. "It's essential to do screenings on depleted gas fields to find one that is the right size and has the right level of depletion."

The Kenai site chosen was an 85 percent depleted gas field that serviced a single Marathon Oil Corp. gas well from October of 2000 until July 2011, producing 23 Bcf during its operational life out of an initial gas-in-place volume of 26.5 Bcf.

Meticulous Construction Planning

Three major buildings were part of the construction at the CINGSA station facility on a 10-acre site in an industrial area of Kenai; the total project footprint including the well pad is 16 acres. The...