The first tanker carrying millions of gallons of liquefied natural gas will arrive at the new terminal in May or June.

The super-cold liquid will be pumped through the Gulf LNG terminal and into massive twin storage tanks, the most distinctive features of the $1.1 billion plant that sits on the horizon southeast of the city. The terminal is in its final phase of construction.

"Our first ship is called a cool-down ship," company spokesman Bill Baerg said. "It's due in early summer."

He said the ship will essentially commission the plant with the liquefied natural gas, or LNG, that it's carrying. LNG is natural gas that has been chilled and condensed to a liquid state.

"It will get the tanks acclimated to minus 260 degrees," he said, the temperature required for the transformation of natural gas.

With the first shipment, Gulf LNG will be up and running, he said. But it won't be considered in service until the fall, Baerg said, "once we make sure everything is operational -- maybe October."

This week there were 500 construction workers on the grounds south of the Chevron Pascagoula Refinery, beyond the end of Industrial Road.

It's mostly electrical workers and insulators on the grounds now, Baerg said. "All the docking and marine work is complete."

The pier and dock will accommodate one tanker at a time and the plan is to dock 150 ships a year, bringing LNG in from other countries.

The liquid will be piped to the storage tanks, then turned back into a gas through a serpentine series of warming pipes in a water bath, and piped throughout the United States to heat homes or run cars.

The tanks have the capacity to store 6.6 billion cubic feet of natural gas, enough to supply the state of Mississippi for a week, company officials have said.

"We just completed the hydrostatic testing," Baerg said, in which the tanks were filled with 26 million gallons of water to make sure the structures are sound. Water is heavier than LNG, so they pumped in enough water to equal the weight of a tank full of LNG.

The LNG terminal will become one of the Port of Pascagoula's biggest clients, generating $3 million to $4 million in rent in addition to cargo fees.

The port, however, will incur the expense of keeping the tanker berth dredged to the needed depth. And part of Gulf LNG's rent will go to the state Tidelands Fund.

The grounds include a 27-foot concrete wall designed to hold off a surge the size of Katrina's.

Baerg is with the Houston-based El Paso Corp., which owns a half-interest in the terminal and which will manage operations. Other owners are Crest Investments of Houston and Angola's Sonangol.

Copyright (c) 2011, The Sun Herald, Biloxi, Miss. Distributed by McClatchy-Tribune Information Services.