Environment & Science

Broken pipes and limited gas storage: Why it's a risky summer for the power supply

Real-time pressure monitoring transmitters are part of a series of new safety enhancements at the Aliso Canyon Natural Gas Storage Facility near Porter Ranch. The transmitters are displayed during a media event on Thursday, Jan. 12, 2017.
Real-time pressure monitoring transmitters are part of a series of new safety enhancements at the Aliso Canyon Natural Gas Storage Facility near Porter Ranch. The transmitters are displayed during a media event on Thursday, Jan. 12, 2017.
Maya Sugarman/KPCC

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The Los Angeles area relies on electricity from gas-fired plants, and that gas could be in short supply this summer, state energy experts announced Tuesday. It means potential power outages in the coming months, with even more of a risk come winter.

The outage risks stem from limits on how much gas Southern California Gas Company is permitted to store underground at the Aliso Canyon Natural Gas Storage Facility, near Porter Ranch, and a state requirement that it withdraw gas only in emergencies.  Four broken SoCal Gas pipelines also mean 27 percent less gas imported from outside the area, exacerbating the potential for shortages, officials said in a joint report.

The restrictions on Aliso Canyon Natural Gas Storage Facility followed the rupture of a gas well in October 2015. The incident turned into the nation’s largest-ever uncontrolled release of natural gas. The well leaked for four months and thousands of Porter Ranch area families were relocated before the well was plugged.

The gas field was renovated and placed back in limited service in July 2017. 

The twice-yearly forecast was produced by the California Public Utilities Commission, the state Energy Commission, the California Independent System Operator which oversees the electrical power grid for much of the state, and the Los Angeles Department of Water and Power.

Tuesday’s warning is the fifth time since the blowout that California’s energy officials have cautioned that the L.A. Basin could face gas or power outages due to limits on storage.

How does a lower gas supply in the L.A. Basin heighten the risk of power outages?

The L.A. Basin is powered mainly by electricity generated at gas-powered plants, along with wind and solar energy. 

The region served by SoCal Gas would, on a peak demand day, use 3.51 billion cubic feet of gas. But with the pipeline outages and restrictions on storage at Aliso, the system can deliver a maximum 3.55 billion cubic feet per day. That leaves a very small margin that could be oversubscribed during a heat wave.

What would happen if there was a heatwave?

On hot evenings, as the wind dies, and the sun goes down, wind and solar power are less available. But Angelenos would crank up the air conditioning - increasing demand for gas.

Without the ability to pull gas out of storage at a convenient location like the Aliso Canyon gas field, the region must use what’s in the pipelines. If the pipelines are carrying 27 percent less gas, it can deliver less to customers and it's harder to fill the company's four gas fields.

Gas moves slowly through pipelines, about 15 miles per hour. But demands for power can peak sharply, especially when wind and solar generation falls off.

During the winter the situation could get even worse, if a long cold weather streak causes Angelenos to turn up the heat. In that situation, power producers could be cut off. However it’s individual gas customers who are at greater risk for losing service in a shortage because they comprise the largest group of users.

What’s going on at the Aliso gas storage field?

Normally, the gas field would be filled up in the summer when gas is cheap and drawn down in the winter when gas costs more. In the past, the field held enough gas to easily fill any gap between the amount big users like power plants might order and the amount they might use during a heat wave.

After the blowout, that surplus of easily-delivered gas was not available because the gas field was shut down. After an overhaul, the gas field was reopened in July 2017, but its use was limited, with withdrawals permitted only during energy emergencies to keep power plants running and homes warm.

State officials have ordered SoCal Gas to keep just enough gas in the underground reservoir (between 14 and 24.6 billion cubic feet) to meet the region’s demands on a streak of hot or extremely cold, high-demand days. Normally, the gas field could hold 86 billion cubic feet, an amount that puts a lot of pressure on its aging wells.

Update: On May 11, The California Public Utilities Commission approved the company's request  to increase the amount of gas it may store underground at Aliso to 30 billion cubic feet.

What does it mean for gas pipelines to be shut down?

The capacity of SoCal Gas’ pipelines is about 27 percent less than last summer, about 2.3 to 2.9 billion cubic feet. The capacity last summer was 3.2 billion cubic feet of gas per day.

“With so many pipeline outages, it will be difficult for SoCal Gas to fill storage to a level sufficient to ensure energy reliability throughout the coming winter,” the report said.

The report added that if SoCal Gas cannot refill its reservoir by November, the region could still be vulnerable to gas shortages.

“Southern California could see a repetition of last winter, with energy reliability hinging on the vagaries of the weather.” 

What is the short-term fix to this problem?

Los Angeles Department of Water and Power is shifting away from gas power toward renewable sources of energy like wind and solar energy. It is increasing the amount of energy storage, which can ease the dropoff of solar-generated energy and help insulate against power outages.

When it looks like gas might be scarce in the L.A. Basin, LADWP lowers its gas burn at plants served by SoCal Gas and shifts its electricity generation to other areas and imports the electricity.

When local power producers like LADWP have to import electricity from outside the area to stretch gas supplies, that costs them more, and those extra costs get passed on to consumers.

What is the long-term fix?

Gov. Jerry Brown last year called on the state Energy Commission to plan for the gas field’s closure within ten years. The future of the Aliso gas storage field is also under study by the California Public Utilities Commission. The agency is looking at the field’s and the aging wells’ vulnerability to earthquakes, and at the amount of pressure the field can sustain when filled with natural gas.

Issam Najm, president of the Porter Ranch Neighborhood Council, says the gas field should be closed because of continual leaks and the danger that benzene in the gas represents to nearby residents.

"For these pipelines to be down for the winter season is inexcusable, and convenient for SoCal Gas," said Najm.

The longer the pipelines remain offline, the more critical it is for the gas system to rely on gas in storage, and the more likely it is that regulators would permit the amount of gas stored underground to be increased.

This article was originally published May 8

This story is part of Elemental: Covering Sustainability, a new multimedia collaboration between Cronkite News, Arizona PBS, KJZZ, KPCC, Rocky Mountain PBS and PBS SoCal.