Jan 3 (Reuters) - Southern California Gas Co (SoCalGas) extended its request to consumers to cut back on their natural gas use through Friday to avoid straining the utility’s system as cold weather blankets parts of its service area:
* In addition to asking homes and businesses to reduce gas use, SoCalGas, a unit of California energy company Sempra Energy , also extended a system-wide voluntary curtailment notice to electric generators from Wednesday through Thursday and Friday.
* Gas supplies are expected to remain tight in Southern California this winter due to limitations on several SoCalGas pipelines and reduced availability of the utility’s biggest storage field at Aliso Canyon in Los Angeles, following a massive leak between October 2015 and February 2016.
* While high temperatures in Los Angeles are expected to reach the mid 60s Fahrenheit (19 Celsius) on Thursday and Friday, according to AccuWeather, the U.S. National Weather Service issued a freeze warning for some inland cities like Riverside. The normal high in Los Angeles is 68 degrees at this time of year.
* Consumer gas demand is expected to reach about 3.6 billion cubic feet (bcf) on Thursday and 3.4 bcf on Friday after hitting an estimated 3.8 bcf on Wednesday. One billion cubic feet is enough to supply about 5 million U.S. homes for a day.
* State agencies forecast SoCalGas’ pipelines and storage facilities could send out up to 4.1 billion cubic feet per day (bcfd) this winter before the utility would have to tap Aliso Canyon, according to a report in October.
* When Aliso Canyon returned to service after the leak, the state mandated the facility is only to be used as an asset of last resort to maintain system reliability after all other resources (other storage facilities and pipelines) have been exhausted.
* SoCalGas can get about 2.7-3.3 bcfd from its pipes and the rest from storage, depending on how many pipeline outages and reductions the utility is able to fix, according to the state’s most recent Aliso Canyon 715 report in July.
* If needed, Aliso Canyon can deliver around 1.0 bcfd. But like all storage facilities, the amount of gas it can deliver will decline rapidly as pressure in the cavern decreases when the utility pulls fuel out.
* State agencies have warned SoCalGas would not be able to meet its 1-in-10-year peak cold day forecast demand of 4.965 bcf without Aliso Canyon.
Reporting by Scott DiSavino; Editing by Bernadette Baum