EPHRATA — The Grant County PUD will buy a new mobile transformer, estimated to cost $4.5 million, as a backup in case of the failure of a permanent transformer.

Will Coe, engineer in the power delivery division, said the new portable transformer will generate 50 megawatts. It would be used in case a transformer failed that was providing power to a large industrial customer.

Utility district staff conducted a study of the district’s existing transformers and presented their findings and recommendations to PUD commissioners Feb. 11.

The PUD does have two portable transformers, Coe said, but neither one is able to provide the electricity needed by some of the large industrial customers. Commissioner Tom Flint asked if two smaller transformers together could provide the power, but Coe said they couldn’t.

Replacing a failed transformer for a large industrial customer could take 10 days to two weeks in optimal conditions, Coe said, and the PUD might not be able to provide an alternate source of power. In that case the customer might have to shut down for the duration of the outage, Coe said.

As a result, employees are recommending the purchase of a portable transformer, Coe said, which also would require the purchase of a special truck to move it. Construction will take about a year from the time it’s ordered.

Flint asked who would pay for the transformer and the required vehicle. General manager Kevin Nordt said the cost would be allocated to the customers that would use it, in this case the large industrial customers.

Utility district officials should make sure customers have realistic expectations about what might happen if a transformer fails, Coe said. Power might be interrupted for anywhere from hours, days to more than a week, he said, and customers should know that.

All of the district’s existing transformers are in good condition, Coe said. They are tested annually.

But whether they stay in good condition is sometimes outside the district’s control, he said. He cited lightning strikes as an example. And at some locations, it would be difficult or impossible to bring in a portable transformer. The study recommended identifying those locations and fixing access.

Cheryl Schweizer can be reached via email at [email protected].