A diesel run powering Wrangell is expected to wrap up on Saturday, according to its electrical superintendent.
Clay Hammer of Wrangell Municipal Light and Power explained the 11-day shutdown of the Tyee Lake hydroelectric facility was planned, in order to conduct annual maintenance on the lines. The main goal has been the replacement of 105 marker balls which make transmission lines visible to passing aircraft. That work, being undertaken by Southeast Alaska Power Agency, began on September 7.
The shutdown began September 6 at 8:15 a.m., at which point Wrangell switched over to its diesel generators for power. The WMLP power plant maintains four of the machines, three of which formerly ran trains. Nicknamed Emil, Ethel and Enid, each machine weighs 66,000 pounds and puts out two megawatts of power apiece. They were built in the 1960s and acquired by Wrangell in the early 2000s. The fourth generator, “Emmy,” has been a mainstay of the plant since 1982, and produces 2.5 megawatts.
“So far they’ve played well together,” Hammer commented, referring to their current run. “It’s been going really well so far.”
As the generators consume pricier diesel, the planned maintenance shutdowns are generally scheduled when demand is low. This is done for several reasons, one of which is the utility’s rate payers. Residents will find an additional fuel surcharge on their bills next month, which covers fuel for the duration of the run on top of base rates. This determined cost is divided between all users, so less wattage used city-wide means a lower surcharge across the board.
On average, during the run the plant has been seeing usage of around 2.5 megawatt hours in the evenings, with about 4 MWh being used during the day. For context, during peak production in the summer, usage can reach around 7.5 MWh.
During those months substantial demand comes from local seafood processors. Trident Seafoods already wound down its operations last month, and while Sea Level Seafoods is still processing, it is not doing so at the same rate as its summer peak.
“Other than that the loads are really small right now,” said Hammer.
Winter demand is even greater than the summer, with a preponderance of electric heating units drawing up to 9 MWh when it gets cold. With Tuesday’s chilly morning fog, Hammer said he noticed an uptick in usage, to about 4.4 MWh. “You can really feel it in the air,” he said.
Average fuel consumption during the diesel run has been 6,100 gallons each day, Hammer explained. The amount has been higher than historical, in large part because the run had been postponed to late summer this year rather than spring. Before the production season kicks into gear and with weather warming increasingly, demand in May or June tends to be at its very lowest, which makes them convenient times for the changeover.
This year’s run had originally been scheduled to cover the last two months of June, but a strike called by the public employees’ union prompted SEAPA to postpone its ball replacement project. The strike lasted only a week, but by that time the project workforce had already been demobilized. In all, the delay is expected to cost the power provider an extra $103,000.
Despite being hampered in parts by fog and by rainfall, the marker ball replacement has progressed as planned. Replacement on Wrangell Island lines wrapped up earlier this week, and the project is now focused on completing the stretch of line on the Cleveland Peninsula.
“It is really super technical work,” Hammer pointed out, with helicopter crews needing pretty favorable conditions in order to successfully make the transition.
Project manager Steve Henson projected the work should conclude by Saturday afternoon, allowing the Tyee facility to resume service provision. Additional maintenance and line improvements which began this week are expected to conclude tomorrow as well.
Reader Comments(0)