The city of Forest Grove has long taken pride in its ability to provide electricity for its residents, but on Monday, about half the city was temporarily powered by Portland General Electric.

This odd, perhaps unprecedented, arrangement with Oregon's utility giant highlights the complexity of what needs to happen to make sure that when you flip a light switch, a bulb goes on.

Forest Grove Light and Power, the city-owned utility, provides electricity to about 8,600 customers. But it doesn't actually create that power. Rather, it buys it from the Bonneville Power Administration, the massive federal agency that generates power in a variety of ways (hydro-electric dams, gas-powered plants, etc.) and sells it to utilities, from relatively small ones such as Forest Grove Light and Power to big ones like PGE.

In Forest Grove, the BPA power comes into the city's three substations, where aluminum piping routes it to transformers before distributing it to lines that service homes, businesses and industrial users.

On Monday, the system broke down at what's known as the Forest Grove Substation, at the north end of Oak Street. 'We're not 100 percent sure of what happened,' said Janet Lonneker, director of the city utility. 'It could have been the snow or it could have been rain. It definitely was a moisture problem.'

Lonneker said somehow, perhaps through a crack in the protective casing, water got into a section of the piping leading to one of the two transformers in the substation. 'It caused some arcing in the aluminum piping and blew everything apart,' said Lonneker, who noted that some of the piping got so hot it melted.

As a result, the fuses in the substation blew, knocking out power to customers. That drop in demand, in turn, triggered a shut-off of BPA's power coming into the substation.

Once BPA officials determined that the problem was with the Forest Grove equipment, they were prepared to turn the juice back on to allow the second transformer, which was not involved in the moisture-related meltdown, to restore power to at least some customers.

But, Lonneker said, when BPA reset its breaker switches, something caused them to malfunction. Suddenly, Forest Grove's largest substation was without a power. Luckily, BPA also uses the substation as a site to distribute some power to PGE, which uses it to serve part of Cornelius.

While PBA worked to fix its switches, it arranged for PGE to send power it obtained elsewhere back to the substation where the city could run it through one working transformer and route it to Forest Grove customers. Within an hour or so, BPA had fixed its switches and was again providing power to the substation.

'We owe a huge debt of gratitude to PGE,' Lonneker said.

Lonneker said the city is in the process of testing the transformer that had been connected to the damaged piping. Until then, she said, the remaining transformer can handle the demand, as city crews have rerouted some of the lines so that they are powered by the other two substations.

At some point, Lonneker said, the city will have to settle up with PGE for the electricity it used. 'As far as I know, we've never had this situation where PGE stepped in and provided power,' she said. 'So I'm not sure just how it will work.'

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