Wrangell and Petersburg began burning diesel this week to partially power their towns. And this could continue for the rest of the winter.

The two Southeast communities run mostly on hydropower supplied by Tyee Lake, which is run by the Southeast Alaska Power Agency.

SEAPA requested the cities turn on their diesel generators to conserve power coming from Tyee Lake. The facility isn’t expected to produce as much power as it usually would this time of year. That’s partly because of a drier fall and winter. And partly because Ketchikan Public Utilities bought some of Tyee’s supply last summer.

SEAPA now says the agency oversold that power to Ketchikan, and it’s now asking that city to pay back for that use. Ketchikan also is burning diesel now, in part to help pay back that hydropower. Wrangell and Petersburg are burning diesel three hours during the mornings, when energy use is at its height. The two cities are taking turns, running diesel every other day.

SEAPA is making its calls day by day, so there’s no knowing how long this could last. But the City of Wrangell expects that if temperatures hover around 20 degrees or below, the diesel generators will continue to run.

While diesel is roughly two to three times more expensive than hydropower, residents in Wrangell should not see an increase on their electrical bill. The city says it hasn’t used enough fuel to kick in the surcharge to customers.