Temperatures that plunged to the deep minuses in Southcentral Alaska during the recent statewide cold snap led to a record demand for natural gas from Enstar as people cranked up their furnaces to ward off the cold, officials said.
After a spate of warm winters, the frigid spell earlier this month was also the first real test for Cook Inlet Natural Gas Storage Alaska, a gas reservoir in the Cook Inlet basin that was once mostly depleted but has been refilled with gas. That stored gas provides a key supply buffer on the coldest days.
The gas from the reservoir played a "critical role," said Travis Renk, pipeline manager for Enstar. It helped reduce concerns that existed in 2012 and earlier of a widespread outage if compressors that help move gas failed, leading to falling pressure in pipes and a systemwide loss of power and heat in Southcentral Alaska.
The giant $160 million gas-storage reservoir came online starting in April 2012. At the time, Southcentral utilities were considering importing gas from outside Alaska because gas-flow rates and future gas-supply prospects had fallen to worrisome levels in the aging Cook Inlet basin.
But supply concerns have been pushed off following an increase in Cook Inlet gas production after state tax credits helped attract explorers and new investment. Enstar and power utilities have signed gas purchase agreements extending as far into the future as 2023. Hilcorp Alaska is the dominant supplier.
The record day for gas use came Jan. 19, when Enstar recorded temperatures colder than minus 20 in Anchorage and colder than minus 40 in the Matanuska-Susitna Borough, Renk said.
The utility moved 253 million cubic feet of gas to keep houses and buildings warm. That beat the previous high of 235 million cubic feet, set one day in January 2009 and nearly equaled on Jan. 16, 2012, officials said. Typical use in January is about 158 million cubic feet.
The underground storage facility, owned partly by Enstar parent company AltaGas of Canada, provided about 40 percent of the gas volume used by Enstar on the recent record day, Renk said.
The gas from CINGSA helped maintain pressure in Enstar's system, reducing the need for operating compressors from six to four. That reduced the risk of problems that could arise if the machines failed, and also allowed for additional backup.
It also meant Enstar had room to supply even more gas if temperatures had fallen further and demand had risen.
On the cold days in 2009 and 2012, gas supply from Cook Inlet was near its "maximum deliverability," nearly pushed to its limits.
"We are in a better place today," Renk said.
Enstar's record day was not the overall record for gas use in Southcentral, home to about half the state's population.
It does not count gas used by power utilities, for example. Also, overall gas consumption in the region is down sharply since the Agrium fertilizer plant shut down in 2007. And ConocoPhillips' Kenai LNG plant, up for sale, has halted exports amid low prices for liquefied natural gas.
Renk said that before the deep cold arrived, utilities and producers held a meeting to walk through worst-case planning scenarios if gas deliverability became a problem.
"Who would we call on, what assets are available, what our options look like," he said. "It was a good exercise to have everyone in the room. And the good part was we didn't have to execute any of those things."