As the electric grid relies more on renewable power sources, particularly in California, natural gas pipeline companies increasingly have to respond to significant and quick changes in demand from gas-fired power plants serving as a backstop to intermittent electricity sources.

Fast responses to power generation demand shifts means pipelines will need to be able to enhance gas deliverability and increase market storage within their service areas, Will Brown, an executive with Kinder Morgan Inc., told the LDC Gas Forums Rockies and West conference. As the California market moves to increased use of solar and wind on its grid, gas "is the only technology that, today, can back up renewables," he said.

"California has made significant strides toward renewable power," Brown said at the Los Angeles gathering Oct. 9. "It becomes increasingly important for natural gas-fired generation to follow this load … to ensure that grid resilience for reliability."

In anticipation of power sector shifts, Houston-based Kinder Morgan has been adapting its suite of services to meet sudden peaks in demand for gas, said Brown, who is vice president of business management for Kinder Morgan's natural gas pipelines unit in the West. While California is investing heavily in battery storage, the technology is not yet at a level to meet interruptions that could occur as the state works toward tough emissions-reductions goals. California recently enacted legislation setting a planning goal of zero-emissions power by 2045.

"As you rely more on intermittent sources of energy, you've got to have backup," Brown said. "When the sun stops shining, the technologies have got to ramp up to be able to meet the load."

Pipelines have to be able to deliver large volumes of gas on short notice, a major shift from traditional model of supplying gas to industrial and local distribution markets. "Natural gas deliverability is the ability to deliver gas at the required location, time, pressure and quantity," Brown said. "The higher deliverability requires more capacity reservation, more known notice, more hourly service, and more reliance on linepack and market area storage."

As nuclear power plants and fossil fuel-powered baseload generation decreases, a pipeline outage or supply disruption in the Southwest could affect the reliability of the grid in California. Estimates show that on peak days when increased demand for residential and industrial gas is combined with increased spot generation demand, the state could be short natural gas after the pivot to renewables, Brown said.

Gas pipeline capacity becomes increasingly valuable as the amount of power coming from interruptible sources rises, Brown said. But currently, California and the desert Southwest have storage and pipeline constraints that could lead to reliability problems, he said, noting that "utilities and power generators must assess their natural gas deliverability needs."

Reductions in local storage, like the cap on injections imposed on Southern California Gas Co.'s Aliso Canyon storage facility, could exacerbate that difficulty during any sudden increase in demand from power generators. After a massive leak at the facility was discovered in 2015, the company was ordered to curtail injections. In July, the California Public Security Commission agreed to up the volume of gas stored at the facility to 34 Bcf from 24.6 Bcf in the wake of regional pipeline outages. The new storage limit is still below Aliso Canyon's historical capacity of about 86 Bcf.

Unless battery storage technology makes massive strides "we believe that as renewable penetration continues to increase, natural gas infrastructure has got to come along with it," Brown said.