LNG plant construction: a huge undertaking.

• Author: Persily, Larry
• Position: OIL & GAS

This update, provided by the Kenai Peninsula Borough mayor's office, is part of an ongoing effort to help keep the public informed about the Alaska LNG project.

Alaska LNG project teams played it by the numbers--really big numbers--in a presentation on construction plans to federal, state, and municipal officials.

Site preparations for the proposed liquefied natural gas (LNG) plant and massive LNG storage tanks in Nikiski would require stripping up to 4 million cubic yards of loose soil, soft peat moss, and other vegetation. That's more than enough to cover a rough trail ten feet wide and a foot deep from New York City to Houston.

Crews would then need to excavate as much as 6 million cubic yards of frost-susceptible material--up to six feet deep in some areas--to prepare the site for construction. Some of the material could be reused as fill, while other material would need to be trucked in to complete the base.

The two domed LNG storage tanks would each measure 305 feet in diameter, more than large enough for a Boeing 747 to spin around inside without scraping its wings.

All of the numbers are approximate and subject to change as the project teams refine the design, they reminded participants at workshops held September 2 and 3 in Anchorage. More than twenty Alaska LNG project team members were at the workshops to brief government agency officials and answer questions.

Add in the jetty, the twin loading berths for LNG carriers, and other components of the Nikiski project, and the preliminary numbers continue adding up:

The project would use eight hundred thousand cubic yards of gravel, three hundred thousand cubic yards of concrete, three hundred thousand cubic yards of armor rock, one hundred thousand tons of structural steel, 6,500 pilings, seven miles of electrical wiring, almost two hundred miles of aboveground piping, and twenty miles of buried pipe.

The trestle to reach the loading berths could be as much as 3,200 feet long--more than half a mile--to reach water deep enough for the LNG carriers to safely maneuver.

Though no substantial dredging would be needed for the jetty and loading berths, an estimated 1 million to 2 million cubic yards of dredging would be required at the temporary dock that would be built for offloading materials from barges and heavy-lift vessels during construction.

The 250-megawatt, gas-fired power plant at the LNG plant site would generate enough electricity to run a city of several tens of thousands of homes.

Peak construction workforce at the Nikiski site would be four thousand to six thousand workers.

Planning Work Continues

The LNG team reported that ongoing engineering and...