Snettisham line goes down, backup generators keep turkeys roasting
Published: 11/24/2011 12:58:20
Updated: 11/24/2011 15:27:01
Power went out across Juneau this Thanksgiving Day morning at about 6:30 AM as the Snettisham hydro-electric power plant tripped offline due to a line fault. After an attempt to re-energize the line from Snettisham failed; AEL&P restored power to the city within about 75 minutes using diesel generators and other hydro plants according to AEL&P's Scott Willis.
At first light, a crew surveyed the line with a helicopter and found a problem about 3 miles from the Snettisham end of the 42-mile line. The crew found that 2 guy wires used to support one of 3 towers - each supporting one of the three conductor cables - had failed. The uphill tower of the group had fallen and leaned into the center tower, causing the conductor cables to short out.
Indications are that the conductor cables themselves are not damaged, and the tower itself doesn't appear to be damaged either. Once the tower can be righted, the lines should be able to be re-energized. Initial estimates based on the aerial survey are that repairs might take 3 to 7 days, depending on the weather and other factors. Crews will have a better idea of the situation once they can get on the ground and perform a closer inspection of the situation.
The Lake Dorothy hydro plant was not effected, and as of lunchtime is online and supplying Juneau with power alongside hydro-plants at Salmon Creek and Annex Creek accounting for 40% of Juneau's power generation. Diesel generators are being used to generate the other 60% of Juneau's power.
"Interruptible" power customers such as Greens Creek Mine have been disconnected from AEL&P and are relying on their own sources of electricity at this time.
Power rates are not expected to increase dramatically as they did when avalanches took out the same lines in different locations in 2008 and 2009. Reliance of 90% diesel power and high oil prices caused rates to skyrocket almost 5-fold after those incidents.
Willis says that there may be a minor adjustment to power rates over a period of many months to account for the diesel used this time, but the situation is "not nearly as bad as the avalanche damage in 2008 & 2009". He clarifies that at this time, it is not known if an avalanche caused the problem. The tower is outside of a known avalanche zone, and wind or other factors in the area may be to blame.
Willis also noted that all information is preliminary at this time until crews can better assess the situation.
By: Mikko Wilson - firstname.lastname@example.org