California natural gas for electricity generation rose nearly 250 MMcf/d in the past week in the wake of Southern California Edison Co. (SCE) taking its 2,300 MW San Onofre Nuclear Generating Station (SONGS) entirely offline. The shutdown came from a scheduled outage at Unit 2 and an unplanned outage of Unit 3 when a small leak occurred last Tuesday.

The California Independent System Operator (CAISO) reported that thermal generation from other sources jumped by more than 1,000 MW as a result of SONGS two units being down.

Unit 3 was shutdown on a precautionary basis when a small leak in its one of the unit’s steam generator tubes was discovered last Tuesday, and two days later damaged tubing was discovered at Unit 2, which was in the midst of planned maintenance.

“With SONGs Unit 2 already down, constraints on several key [natural gas] pipelines delivering gas to the Southern California Gas Co. (SoCalGas) system could have significant implications for Southern California cash and forward markets, particularly if SONGS No. 3 stays offline for an extended period of time,” said Bentek Energy’s “California/Southwest Observer,” which monitors gas supply/demand in the region.

“Near term, spreads to the SoCal [system] may widen as shippers must cover higher variable costs on alternative routes in order to meet incremental gas demand,” Bentek said.

Among its other observations and estimates was the potential for having up to 500 MMcf/d in incremental gas supplies to serve power demand. And some of the incremental supplies may have to go to more expensive variable costs because of the known constraints on flows in the Transwestern and Kern River pipelines serving the area.

There are also two other planned outages at major nuclear generating plants in the region slated for early spring: 1,247 MW Unit 3 at Palo Verde Nuclear Generating Station in Arizona (mid-March to mid-April), and the 1,122 MW Unit 1 at Pacific Gas and Electric Co.’s Diablo Canyon nuke plant (April 22-May 31), Bentek’s report said. Further complicating this picture is the fact that the SoCalGas system is planning to curtail gas supplies from the Transwestern-Needles receipt point as part of a pipeline integrity testing program April 9-May 5.

An SCE spokesperson at the SONGS site would not say when one of the units was scheduled to come back online, although he noted that the planned Unit 2 outage was slated to run two months.

He did reiterate that both SONGS units are in “safe shut-down mode. Unit 2 was shut down Jan. 9 for a planned maintenance, technology upgrade and refueling outage. Unit 3 was shut down Jan. 31 when a small water leak was detected.”

In addition, the tube inspection process continues at Unit 3 to determine the source of the water leak, he said. The tube inspection process also continues at Unit 2 to verify preliminary findings made public last week by the Nuclear Regulatory Commission.

“Several sensitive radiation monitors near Unit 3 detected very slight increases in radiation levels. No other plant detectors measured any change. Because we immediately shut down the unit, the localized increase stopped the same day it was discovered”

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