LOS ANGELES, Jan. 26, 2017 /PRNewswire/ -- Southern California Gas Co. (SoCalGas) today lifted the "SoCalGas Advisory" asking all customers to reduce their natural gas use. The advisory was called on Monday at 7 a.m. in response to increased demand for natural gas resulting from cold weather. The system-wide curtailment watch for noncore customers (large commercial and industrial customers, including electric generation plants) has also been lifted. Both the SoCalGas Advisory and Curtailment Watch ended today at 1 p.m.

On Jan. 24 and Jan. 25 cold weather conditions led to hourly customer demand on SoCalGas' system that significantly exceeded gas supplies being delivered through interstate pipelines and the company's other storage facilities. Natural gas withdrawals from Aliso Canyon played a critical role in helping SoCalGas meet those peak hourly demands and avoid service interruption to large customers, including electric generators, refineries, and other critical service providers such as hospitals, airports and manufacturers.

Withdrawals from Aliso Canyon were made in accordance with the Aliso Canyon Winter Withdrawal Protocol established by the California Public Utilities Commission (CPUC).

Withdrawal Event Summary

Rapid changes in customer demand over the last two days are examples of the sudden peaks SoCalGas regularly experiences with changes in the weather. The company coordinates with the California Independent System Operator and customers to manage these hourly changes in demand to help prevent service interruptions. 

Temperature lows in most parts of the region on Jan. 24 and Jan. 25 were in the 30s at night. On Monday and Tuesday, SoCalGas delivered almost 4.1 billion cubic feet of gas, the highest demand so far this winter, according to company data.

Natural gas travels slowly through pipelines. It takes 3-4 hours for gas traveling from the California border (where it enters the SoCalGas system) to customers in the LA Basin. In the morning hours on Jan. 24 and Jan. 25 hourly customer demand on SoCalGas' system significantly exceeded gas supplies being delivered through interstate pipelines and from our other storage facilities.

In an effort to meet the peak hourly demand, SoCalGas placed all other storage fields on maximum withdrawal.  Even at maximum withdrawal, that was not sufficient to meet the peak hourly customer demand.

To help maintain the reliability of natural gas and electricity service across the region, SoCalGas withdrew natural gas from Aliso Canyon. The withdrawal was consistent with the Aliso Canyon Winter Withdrawal Protocol established by the CPUC.

Without withdrawals from Aliso Canyon, the demand on the system over the last two days could have resulted in curtailments to non-core customers, including power plants, refineries, and hospitals.

Measurements of Gas Withdrawn from Aliso Canyon

• On Jan. 24 approximately .03 billion cubic feet of natural gas was withdrawn from Aliso Canyon over a two-and-a-half-hour period between 7:25 a.m. and 10:50 a.m. The peak flow rate during this period was about .013 billion cubic feet (13 million cubic feet) per hour.
• On Jan. 25 approximately .02 billion cubic feet of natural gas was withdrawn from Aliso Canyon over a two-hour period between 7 a.m. and 9 a.m.
• Approximately 14.8 billion cubic feet of working gas inventory remained in the field after the withdrawal.

Additional Monitoring During Withdrawals

Verified readings from SoCalGas' network of eight pairs of fence-line monitors and other detection systems show normal background levels over the withdrawal periods.  Furthermore, additional methane detection patrols showed no increased levels of methane at wells or equipment being used for withdrawal.

Data collected by a community air monitor shows background levels of methane were at their lowest levels yesterday during the time that Aliso Canyon was withdrawing gas to meet increased customer demand.  All of the levels detected by the methane monitor were within normal background ranges.

Additional data collected by The South Coast Air Quality Management District is consistent with readings from SoCalGas and community monitors and is available here:  http://www.aqmd.gov/home/regulations/compliance/aliso-canyon-update/air-sampling/air-montoring-activities/continuous-methane-monitoring-data.

About Southern California Gas Co.
Southern California Gas Co. (SoCalGas) has been delivering clean, safe and reliable natural gas to its customers for more than 145 years. It is the nation's largest natural gas distribution utility, providing service to 21.6 million consumers connected through 5.9 million meters in more than 500 communities. The company's service territory encompasses approximately 20,000 square miles throughout central and Southern California, from Visalia to the Mexican border. SoCalGas is a regulated subsidiary of Sempra Energy (NYSE: SRE), a Fortune 500 energy services holding company based in San Diego.

SOURCE Southern California Gas Company