Southern California Gas (SoCalGas) is working to clean up the biggest known gas leak in U.S. history at one of its natural gas storage facilities in the Los Angeles region.

The leaking methane — a greenhouse gas over 80 times more potent than carbon dioxide — threatens the state's progress in the fight against climate change. It could also compromise the supply of natural gas, which is predominantly methane, to electricity generating plants and gas heating customers in the Southern California region.

Fines will eventually be levied against SoCalGas for the ongoing release of what initially was 25% of California’s monthly methane emissions and could be as much as 15% of the hourly greenhouse gas emissions from the U.S. natural gas industry. 

The company expects to stop the leak in April, meaning LA basin residents will have to live with a plume of methane over their communities until at least then. But beyond the localized consequences, the massive leak raises some larger questions about the electricity sector's move to natural gas as a more environmentally-friendly resource than coal: Since studies suggest that methane leakage of more than 3% of total production can negate any climactic benefits over burning coal, what can the electricity and gas sectors do to limit and eliminate leaks? And what are the alternatives to a move toward natural gas?

The leak

The LA basin leak was discovered October 23 during one of SoCalGas’s twice-daily well observations at its Aliso Canyon natural gas storage facility. The repurposed oil field is in the Santa Susannah Mountains about a mile from the upscale Porter Ranch suburb at the northern edge of Los Angeles’s San Fernando Valley. Its 115 wells hold up to 86 billion cubic feet of natural gas for distribution to residences, businesses, and electric utilities in the L.A. basin.

Planing to stop the leak began immediately and notifications to the appropriate regulatory agencies were sent on October 24. By October 25, a dozen or more local and state agencies were involved.

Porter Ranch residents are angry and frightened. The city is moving to close nearby schools. Those who aren’t staging protests and demanding action are evacuating. As of December 16, 1,807 households had been relocated.

The actual cause of the leak is still undetermined. SoCalGas’s hypothesis is the leak is no more than 500 feet down in the column used to move gas in and out of the well. But six attempts to stop the flow by pumping in fluids failed, according to Spokesperson Kristina Lloyd.

The company is now drilling to the caprock, 8,000 feet down, to close the opening to the column. It is expected to take three to four months.

“It is too early to know what is broken or leaking,” Lloyd said. “Once we get the flow of gas stopped, we will do a root cause analysis.”

Such a relief well, according to Lloyd, “is an established approach to dealing with leaking wells when they don't respond to other procedures.”

The well, she said, is similar to the relief well BP’s engineers drilled to stop oil flowing into the Gulf of Mexico in 2010 after the Deepwater Horizon disaster.

Massive scale

Currently, the EPA estimates that 1.8% of methane produced in the U.S. escapes into the atmosphere, but studies have shown methane leakage in some systems is nearly four times that amount, putting it well over the 3% threshold that likely cancels out gas's climactic benefits over burning coal for electricity. 

The LA basin leak is large enough to have a significant impact on overall greenhouse gas emissions from California and the nation at large.

November 7 and 10 flyover data from Aliso Canyon found an emission rate “of approximately 44,000±5,000 kilograms of methane per hour and 50,000±16,000 kilograms of methane per hour,” according to the California Air Resources Board (CARB) November 20 preliminary report.

This “suggests that the Aliso Canyon gas leak would have added approximately one-quarter to the regular statewide methane emissions from October 23 to November 20,” CARB reported.

“It about doubled the amount of methane in the Los Angeles basin,” CARB Spokesperson David Clegern told Utility Dive.

By November 28, the flow had spiked to 58,000±12,000 kg of methane per hour, but the December 12 measurement found it had slowed to 36,000±6,800 kg per hour, according to CARB's follow-up report.

While methane is only 9% of California’s total greenhouse gas emissions, it is far more harmful to the atmosphere than carbon dioxide.

“The IPCC now states that methane is more than 100-times more powerful for the first decade after emission, 86-times over a 20-year period, and 34-times over 100 years,” according to Cornell University professor Robert W. Howarth, who helped write one of the first academic studies on the climactic impacts of shale gas in 2011.

“This is a big deal. It is a lot of hydrocarbons escaping into the environment over a long period of time,” Howarth said.

Climate change activist and 350.org head Bill McKibben compared the Alison Canyon leak to the Deepwater Horizon disaster in conversations during the Paris climate change talks, Howarth recalled. “He said this is analogous except it is colorless and odorless.”

Based on a rounding of the CARB-reported 50,000 kg per hour flow rate, Howarth said, the LA basin leak is likely as much as 10% to 15% of the entire natural gas industry’s hourly greenhouse gas emissions.

“This is a rare event,” SoCalGas's Lloyd acknowledged. “We’ve never seen anything like this at any of our facilities.”

The well

The Aliso Canyon facility is one of the four SoCalGas operates to supply a service territory that extends from Central California to the Mexican border. Processed natural gas, ready for distribution is stored there for “quick and effective response to real-time L.A. basin demand,” Lloyd said.

The leak is from only one well in a “naturally-occurring underground reservoir that held oil and gas for millions of years,” Lloyd said.

The oil and gas in the wells was depleted by drilling that began at the site in 1938. The wells there have been used for gas storage since 1941. SoCalGas has operated the facility since 1972.

The facility is maintained in accordance with safety regulations established by the Department of Oil, Gas and Geothermal Resources (DOGGR), the California Public Utilities Commission, and other local, state and federal agencies. DOGGR has already opened an investigation into causes.

“We are focused on mobilization of all the resources needed to stop this leak as quickly and safely as possible,” Lloyd said. “Work to halt the leak is happening around the clock.”

“I don’t know what would cause a pipe to leak,” Howarth said. “They must not have a shut-off valve between the storage and where the break is. That’s a problem.”

Because methane is lighter than air and satellite imagery has demonstrated a plume of methane over the leak, the Federal Aviation Administration banned aircraft flying below 2,000 feet from going within a half-mile radius of the well site through March 8. 

Drilling to the caprock means dealing with adjacent gas at high pressure, Howarth said. "I am sure they are worried about an explosion, but I am also sure they are trying not to worry people."

"But," he said, "a fire cloud in the air seems possible.”

Supply threat?

The primary off-taker of gas from Aliso Canyon is the Los Angeles Department of Water and Power (LADWP), according to Lloyd. Its 1.4 million electricity customers make it the biggest U.S. municipal electric utility.

Aliso Canyon also supplies natural gas power plants that generate electricity for Southern California’s many other investor-owned and publicly-owned electric utilities and for millions of heating customers, she added.

“My understanding is that SoCalGas has its supply of gas for the winter there,” CARB's Clegern said.

“A significant amount of gas is being lost,” SoCalGas's Lloyd said. “And we are not injecting into this facility now, we are only withdrawing because we want to bring the pressure down.”

The facility is critical to SoCalGas being able to provide "safe and reliable gas across the region," Lloyd said. "My understanding is there is so far no shortage of gas delivery to customers,” she added.

As to longer term supply impacts, SoCalGas has three other storage fields and the ability to bring in a large amount of daily supply, she said. But “if the Aliso facility should be closed or put on hiatus for an extended time, electric generation could be affected,” she said.

Because the failure of SoCalGas to deliver needed supply has such wide-ranging implications for consumers, investors, and financial markets, Lloyd was unwilling to comment further. “We don’t want to put out anything that is speculative," she said.

The loss of the Aliso Canyon facility supply “should have very little impact,” according to California Energy Commission (CEC) Chair Robert B. Wiesenmiller.

But in the last week, as cold hit Southern California, “natural gas storage balances in the SoCal Gas system have dropped about 2%,” he said on a media call last week.

The small drop is not a threat to Southern California’s supply, he said, but the CEC is monitoring closely because “the reliability of gas supply is critically important to both gas and electric customers and protecting public safety.” 

But some outside observers think the 2% drop could be more important to the electricity sector than Wiesenmiller said. 

“Flexibility would be a bigger concern than raw supply,” according to Center for Energy Efficiency and Renewable Technologies Executive Director V. John White. “That storage is an important cog in the way the gas company handles swings in gas demand throughout the day.”

In a state getting nearly a third of its electricity from renewables, those swings are increasingly common “but the company can probably handle the issue unless the whole facility is shut down,” he said. 

Methane leaks and the electricity sector

While the Aliso Canyon leak primarily involves SoCalGas, a natural gas facility, many of the consequences and lessons apply to the electricity sector as well. Natural gas generated 54% of California's electricity from January to May of this year, according to EIA data, and utilization of the resource nationwide is expected to grow significantly in the next decade as utilities shift away from coal generation in response to the Clean Power Plan.

The idea behind the shift to gas is that it's a cleaner alternative to coal power plants that still generate over a third of the nation's electricity. But the Aliso Canyon leak, experts say, is a prime example of how those good intentions may not be realized.

“Oil and gas production, along with natural gas distribution, is a significant source of methane emissions and regulatory efforts are under way to reduce emissions from those sectors," CARB's preliminary report said, warning that such leaks could compromise the state’s goal to cut methane emissions 40% from current levels by 2030.

“The relative magnitude of emissions from the leak compared to other sources of methane in the State underscores the urgency of stopping the gas leak," the report said. 

“My guess is they are doing everything they can to solve it as quickly as they can but why it is acceptable for industry to build infrastructure with this danger is beyond me,” Howarth said. “The climate goals can’t be met without reducing methane.”  

Because of its abundance and because its carbon dioxide emissions are lower per unit of heat energy than coal or oil, Howarth wrote in a 2011 paper that many say shale gas can be a “bridge fuel” to a renewable energy future.

But “significant quantities of methane are emitted into the atmosphere from shale gas development,” it documents.

“When methane emissions are included, the greenhouse gas footprint of shale gas is significantly larger than that of conventional natural gas, coal, and oil," the study concluded. 

The share of shale gas in overall U.S. natural gas production has grown significantly this decade. 

In the last decade, production of natural gas from shale has gone from negligible to over 40% of 2013’s U.S. natural gas supply and 14% of its fossil fuel energy in 2013, according to a recent study of methane authored by Howarth. 

Along with animal agriculture, the oil and gas industry is the major source of methane, Howarth told Utility Dive. “And they are so sloppy with it and so cavalier about it, it is just amazing to me.”

The Aliso Canyon leak is exemplary of a natural gas industry that relies on antiquated, inadequate infrastructure until it fails, he added.

The scientific community is talking about this leak as indication of what a transition to increased reliance on natural gas could mean, said University of Cincinnati Geology Professor and methane expert Amy Townsend-Small.

“Incidents like this could become more common," Townsend-Small, a member of the team at Cornell that published the 2011 paper on methane emissions. 

Because methane is more potent that carbon dioxide in the short term, it is already "responsible for nearly half the warming impact of current U.S. emissions over the next 20 years,” she and her colleagues wrote in a summary of their research.

Leaks like this could turn the bridge fuel into a climate change accelerator, but at present, natural gas plants are still needed to balance out the intermittent generation of renewables. They and other plants must also provide power when renewables aren't generating.

“Right now, you’re going to be building a lot of renewables at utilities,” Brian Wolff, vice president for policy at the Edison Electric Institute told Utility Dive for a separate article on decarbonization. “You're still going to have, in the short term, those [natural gas] peakers as backup until storage as a technology comes to the scale that we need it to come to.”

"That [storage] technolgoy is not where it needs to be, so you still need peakers to turn on major facilities and run operations," he added, "so it cant be 100% renewable."

As energy storage technology matures and its costs decline, however, Wolff and other sector leaders expect that it one day could be a large-scale replacement for natural gas generation, creating grids that run almost exclusively on renewable generation. Already, some at California utilities are talking about a "future with no more gas turbines."

Those techological advances aside, methane continues to leak in the LA basin, and SoCalGas says it is working around the clock to plug the well. 

“We are doing everything we can to stop the flow of gas and get people back in their homes,” Lloyd said. “There is nothing we want more than to stop this leak.”