With Aliso Canyon, California’s largest natural gas storage facility, unavailable for summer electric peak demand short of an emergency, Southern California Gas Co. (SoCalGas) is warning state officials of potential issues.

Critics, including residents who were displaced during a four-month storage well leak that ended in February 2016, argue that the region was unaffected by the 86 Bcf storage field closure last summer and last winter, despite the utility’s public concerns. In April a study commissioned by Los Angeles County concluded that Aliso was not needed to ensure regional energy reliability.

However, in a letter to the state’s major regulators, the Sempra Energy utility again said it may have trouble this summer maintaining system reliability, given that restrictions remain in effect on the use of the 3,600-acre facility.

The Los Angeles-based gas utility, in a letter to the California Public Utilities Commission, California Energy Commission and the California Independent System Operator, indicated it was unsure it could meet this summer’s variable energy demand and also prepare for next winter’s gas demands.

“The state was lucky this past year to have experienced a mild summer and winter,” the letter stated. “For the upcoming summer and winter seasons, Californians cannot rely on luck, and energy reliability should not depend upon unusually mild weather conditions.”

SoCalGas emphasized that its system has been “designed and operated” with the injection, withdrawal and storage capacity of all the regional storage fields as “integral parts of the overall system,” citing national energy and weather projections that could spell trouble this summer.

The U.S. Energy Information Administration’s (EIA) latest statistics indicate that the Pacific region, including California, Oregon and Washington, was 6.4% below the five-year average for working gas in storage as of the end of April (233 Bcf versus the five-year average of 249 Bcf).

But abundant hydroelectric power is expected to help this summer as California and the Pacific Northwest are looking at above-normal water levels. The state’s electric utilities’ net generation from conventional hydroelectric power was about 6.9 million MWh over January and February, compared with the same period last year, EIA said.

However, SoCalGas noted that the National Oceanic and Atmospheric Administration has forecast a 60-70% chance of above-average temperatures in California this summer, which could strain energy systems on peak demand days.