For most days in 2017, the share of electricity generated from natural gas has been near or below previous five-year (2012–16) minimums in the California Independent System Operator (CAISO) region. Rising hydro and solar power output lowered the overall contribution of gas, but there are fresh concerns over a repeat in gas shortfalls this summer, with operating restrictions on SoCalGas's Aliso Canyon field still in place.
Rising hydroelectric output in CAISO, along with a steady rise in grid-connected solar power generation, has offset lower gas generation so far in 2017. However, in early May, unseasonably warm weather led to an 80% increase in gas use for power generation compared with daily averages in April.
Through May 8, California has averaged 38 inches of snow-water equivalent since the first of the year, about double the precipitation through that point in 2016. In the first four months of 2017, average daily solar output has increased by 27% over the same time period for 2016, according to EnergyGPS data.
Warmer weather this summer will likely result in increased use of natural gas, notably for electric air conditioning. The availability of natural gas in Southern California has implications for regional power generation – particularly as there are still bottlenecks in gas supply due to operating restrictions on SoCalGas's Aliso Canyon field, an underground natural gas storage facility with a capacity of 86 billion cubic feet (Bcf), or 64% of SoCalGas's total storage capacity.
Withdrawals from Aliso Canyon gas storage are still impacted by a leak that was initially detected in late October 2015 and plugged in February 2016. At the time, gas storage levels plunged to 15 Bcf, and inventories at all of SoCalGas's storage facilities fell to just 60 Bcf throughout most of the past year.
The past summer was marked by severe gas shortages and interventions at regulatory and state level to avoid electricity shortages: In June 2016, the California Public Utility Commission (CPUC) conditionally authorized SoCalGas to withdraw the remaining 15 Bcf at Aliso Canyon.
Technical difficulties to replenish the Aliso Canyon in summer 2016, limited availability during the winter withdrawal season: A total of 19 Bcf was withdrawn from the SoCalGas system from November 2016 through the end of March 2017, including withdrawals from Aliso Canyon during a two-day cold snap in late January. By comparison, over the five prior November-through-March periods, withdrawals averaged nearly 60 Bcf, ranging from 31 Bcf to 103 Bcf. As of May 16, SoCalGas's inventory stands at 43 Bcf.
On May 22, a Joint Agency Workshop on Energy Reliability in Southern California will be held by the CASIO grid operator, California Energy Commission (CEC), California Public Utilities Commission (CPUC) and the Los Angeles Department of Water and Power.
Daily statistics on regional temperatures, electric power loads, natural gas flows, SoCalGas send-out, changes in SoCalGas inventories, and spot natural gas and electric power prices can be found in the EIA’s Southern California Daily Energy Report.