Low lake levels blamed for increasing COPA

Electricity rates in Juneau will go up in April, due to low water levels in the mountain lakes supplying Juneau’s hydropower.

Electric utilities in Alaska are allowed to adjust their rates with the costs of producing electricity.

Alaska Electric Light and Power calculates the Cost of Power Adjustment quarterly.  It will increase to 1.2 cents a kilowatt hour through June. Right now, AEL&P customers are enjoying a COPA credit of .07 cents a kilowatt hour.

Generation engineer Scott Willis says the problem began last fall, when October was one of the driest months on record.

Willis says it’s important not to draw down the lakes to the point where the company has to use diesel, and the company did not have to use the expensive fuel this winter to supplement hydro.

“I have a lower limit that I don’t want the lakes to go below at different times of the year.  Crater Lake was right on its low limit and Long Lake was below its lower limit,” Willis says.

Lake levels were low enough that the company turned off power to Greens Creek Mine in December, forcing the Admiralty Island mine to produce its own electricity from diesel.  The mine buys surplus power and is considered an “interruptible customer,” as are “dual-fuel” customers that also have another source of electricity.  They were shut off in January, but AEL&P has since reconnected dual-fuel customers, now that lake levels are coming up.

Willis says February’s wet, warm weather is beginning to turn things around and Green’s Creek will be reconnected to hydropower when lake levels are higher.

Revenues from surplus power customers help keep rates down to AEL&Ps main customers.

“We want to sell as much energy as we can to Greens Creek because that keeps our rates low to our firm customers.  But we don’t want to sell too much and have to generate our own diesel, so it’s always a balancing act based on how much rain I’m going to get a few months from now,” Willis says.

At 1.2 cents per kilowatt hour, the Cost of Power Adjustment will add about $10 a month to a customer using an average of 850 kWh. The COPA will be re-calculated again in June.



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