California regulators approved a proposal to inject more natural gas at Sempra Energy’s Aliso Canyon Natural Gas Storage Facility, site of the worst methane leak in US history.

The decision is designed to protect against a spike in natural gas prices like the one that took place last winter when some residents saw monthly energy bills hit $1,000 or higher, the California Public Utilities Commission said in a statement. The temporary increase in storage capacity could lead to savings from $200 million to $450 million for Southern California customers, the commission said.

Separately, the commission said it is on track to issue a proposal on alternatives to replace Aliso Canyon and reduce the state’s reliance on the site. The 2015 leak from a broken well at the facility spewed an equivalent of a year’s worth of greenhouse gas emissions from more than 500,000 cars and has cost the company nearly $2 billion to settle claims.