The Southern California Gas Co. — which supplies gas to Edison and others throughout the region — the California Energy Commission, the California Public Utilities Commission, the California Independent System Operator and the Los Angeles Department of Water and Power collaborated on the analysis. Their warnings highlight the facility's critical position in the region's supply chain. Aliso Canyon's gas bolsters the region's power plants when summer air conditioning strains the system. In the winter, its reserves make up for the high demand from heating buildings. Businesses and millions of homes depend on its availability. Since regulators halted underground gas injections during the leak, Aliso has dropped to 15 billion cubic feet of gas, less than a fifth of its capacity.