The Imperial Irrigation District will pay a $3 million civil penalty to energy regulators and spend $9 million on reliability improvements as part of a deal to resolve charges that it contributed to a major 2011 southwestern blackout.
The deal with the Federal Energy Regulatory Commission (FERC) is the second such settlement to arise out of the cascading power outages that left about 5 million people across the southwest without power. Arizona Public Service, which owns the 500kV Hassayampa-North Gila line blamed as the source of the outage, last month agreed to pay a $3.25 million fine.
The Imperial Irrigation District serves about 145,000 customers and owns part of two parallel east-west transmission corridors that go into southern California: the Southwest Power Link and Path 44. After the initial trip of the Hassayampa-North Gila line, FERC said power flows carried by the Imperial Irrigation District spiked, causing many of its transformers to trip and eventually caused it to lose 929MW of firm load.
FERC said it found the utility had violated a number of reliability standards during the event, including a failure to have valid next-day and current-day plans of its transmission operations. The commission also said the irrigation district’s long-term planning studies failed to consider what would happen if the Hassayampa-North Gila line tripped.
As part of the settlement, the Imperial district neither admitted or denied violating reliability standards. The utility in the deal has agreed to make the $9million in reliability upgrades by the end of 2016, and the $3 million civil penalty will be split between the US Treasury and the North American Electric Reliability Corp., which develops reliability standards.