EPHRATA - The Grant County PUD is turning to Battelle Memorial Institute to find the cause of three power outages that occurred last year along Moses Lake's Wheeler Corridor.

As part of a $91,087 contract with the district, the Richland-based Battelle is providing in-depth sampling, analysis and testing of the air and surfaces in the Wheeler Corridor, according to Sarah Morford, a district spokesperson, on Thursday.

At the time of the outages, unknown contaminants were found on electrical equipment.

It was initially believed the October outages were caused by misting weather conditions in the area causing contaminants on substation equipment to fault, she explained.

The PUD does not know what the contaminants are.

What's described as "heavy tar like contamination" was found at the Silicon, Sieler and Upper Coulee substations, according to an outage report written by a PUD manager.

According to the report, maintenance cleaning of Silicon and Upper Coulee substations was deferred by a REC Silicon staff request in the early summer.

"Ongoing attempts over the summer to establish an outage for cleaning and known switch and contamination issues proved unsuccessful," the report states. On "September 15, REC put on notice that three to 12 hour outages would be required in 2012 to complete deferred work and cleaning at Upper Coulee and Silicon substations. No imminent threat to reliability was suspected at the time. Contamination of all surfaces and corrosion of metal parts is a growing problem at Silicon substation."

Battelle's work should be done by August and is the second of two contracts to address the issues.

The district's first contract was with Oil Analysis Lab, of Spokane, to analyze the composition of the contaminants.

At the PUD's Upper Coulee and Silicon substations, conductive metals were found to have caused insulator flashovers and outages.

"Despite these two outages, Grant PUD has an excellent track record of keeping the power on for our customers. At this time, we are unclear as to what is causing the contamination in the Wheeler Corridor area," Morford, of Grant PUD, stated.

Once completed, the district releases a report to the public about its findings.

"In the interim, we are working on our system and with our customers in that area to ensure they continue to receive the excellent reliability they've come to expect from Grant PUD," she commented.

In October, REC Silicon announced the outage resulted in 100 percent power loss to its Moses Lake facility.

The company reduced its production target from 19,000 metric tons to 18,500 metric tons.