by Scott Willis, Power Generation Engineer

Since Juneau is not connected to a larger power grid, all the electricity consumed in our community must be generated locally.  Over 98% of our power comes from renewable hydro generation, most of which comes from the Snettisham Hydroelectric Project.  The rest of our hydropower is generated at our Annex Creek, Salmon Creek, and Gold Creek Hydroelectric Projects.

But generating the power is only part of the process.  The electricity then has to be delivered over transmission lines to power substations around town, and then distributed to the homes and businesses in the community.  

What causes power outages?

A variety of problems can affect the power lines.  Anything that allows the electricity to find a path to ground, or allows two wires to contact each other, such as a tree or animal in the line, causes a “short circuit” or fault.  When this happens, large circuit breakers automatically open the line to prevent the flow of dangerous or destructive current.  When these circuit breakers open, it interrupts the flow of electricity to everyone beyond the fault.  If a fault happens on our main line from Snettisham, it results in an area-wide outage.  If it happens on the line serving a single home, only that home will be affected.

I've seen my lights flicker.  Why is that?

Sometimes you may see the lights in your home dim or flicker momentarily.  This can be caused by a fault and breaker opening in another part of the system, which briefly disturbs the electrical flow throughout the system.

Can't you do anything about power outages?

Many of our lines go through very rugged terrain, or through heavily forested areas.  While AEL&P has a preventive-maintenance program established to keep power line right-of-ways cleared of trees, the lines in our community will always be susceptible to problems caused by trees, birds, other animals -- or even people.  Customers should protect sensitive electrical equipment with surge suppressors, and may want to consider UPS’s (uninterruptible power supplies) for important equipment.

What should I do if there is an outage?

If the power goes out at your house, check to see if your neighbors have power.  If they do, then the outage is only affecting your home and we won’t know about it until you call the number listed in the phone book.  If your neighbors are also without power, the outage is probably large enough that we know about it already.  In that case there is no need to call unless you have information about the specific location of the problem.  During large or lengthy outages we try to keep the community informed through announcements on our local radio stations.  Listening to these with a battery-powered radio will keep you informed about an outage.

Our crews respond to all outages and continue working until power is restored to all of our customers.  Even though outages will always be a fact-of-life with any electrical system, rest assured that we are doing are best -- 24/7 -- to keep the lights on in Juneau.