Quake probe clears power utilities
Electric companies on the Big Island and Maui pass a review by an outside consultant
Consulting engineers concluded that the Maui and Big Island electric companies' response to the Oct. 15 earthquakes was "reasonable, responsible and in the public interest."
Maui Electric Co. and Hawaii Electric Light Co. submitted reports yesterday from Power Engineers Inc. of Hailey, Idaho, to the Public Utilities Commission. The consultant reached a similar conclusion in a report on Oahu's Hawaiian Electric Co. released in December.
The engineering firm prepared the reports as part of a PUC investigation into the islandwide power failures caused by the 6.7-magnitude earthquake, and the 6.0-magnitude quake that followed, off the coast of the Big Island.
The Big Island, which bore the brunt of earthquake damage, initially lost power in all but a small area on the east side of the island. Power was restored to 98 percent of customers by 12:45 p.m. Oct. 15, less than six hours after the quake.
Maui Electric Co. had an islandwide blackout but was able to restore full power by 2:32 p.m.
On Oahu, gradual restoration of the grid gave some residents electricity 10 hours after the quake, but it took HECO more than 18 hours to restore electricity to all but 2,200 of its 291,000 customers.
On the Big Island, the sequence of events made it possible for the power system to be stabilized quicker, according to the Power Engineers report. The quake tripped relays, shutting down power to the west side of the island. The reduction in customer load tripped generators, but automatic load-shedding enabled the grid to stabilize and not shut down completely.
The report said it is difficult to make meaningful comparisons about the restoration of power in the three systems because of various factors including the number of customers. Maui and the Big Island use generators that are diesel engines and combustion turbines, which can be started more quickly than the steam units used on Oahu. Considering the different factors in each case, "There were no discernible delays in restoring power to the HECO system compared to the HELCO and MECO systems," said the consultants.
"Operations personnel in all three systems responded in an appropriate and professional manner to protect equipment and prevent systemwide collapse where possible," said the consultants.
There was a public outcry by state officials and customers regarding the time it took for power to be restored on Oahu. HECO officials told the PUC that the utility had to restore power gradually to prevent extensive damage to the system. HECO hired Power Engineers to assess its handling of the emergency situation after the PUC opened an investigation into the October outages.
Summaries of the reports will be posted on www.heco.com. The public can read the complete reports at the PUC offices at 465 S. King St.