ANCHORAGE, Alaska (KTUU) – While the exact cause of Monday’s power outage that left tens of thousands of people in Anchorage and Mat-Su in the dark remains under investigation, Chugach Electric officials are explaining the intentional precautionary measure known as “load shedding” that was taken to prevent a widespread blackout in the Railbelt.
For about an hour Monday evening, more than 45,000 people in Anchorage and another 24,000 in Matanuska-Susitna Borough were without power.
Both Chugach Electric and the Matanuska Electric Association referred to the problem as a “load shedding” event in social media posts.
Julie Hasquet, communications manager for Chugach Electric, said the cause is still under investigation, but without the use of so-called load management, the situation could have been even worse.
“Load shedding is a great tool for us to manage the situation when major generation assets go offline in the Railbelt,” Hasquet said. “In this case, it was Chugach and MEA. We both shed load at the same time, which allowed us to stabilize the system, figure out the problem and get people back online. So the load shedding plan and program absolutely worked as intended and prevented a major event.”
Load shedding is a form of electricity load management designed to prevent the power grid from becoming overloaded.
Periodic power outages are designed to reduce electricity consumption from primary sources until demand falls. This is often seen as a last resort to prevent power grids from becoming unstable and causing widespread outages.
Electric Chugach said in his contribution on Monday that a load shedding event occurs when a major power generation source fails somewhere on the Railbelt and this could have been caused by a “tree or something else”.
In a separate postThe Matanuska Electric Association confirmed that two Chugach power plants were out due to a fault along the northern interconnector.
Load shedding is especially important for a place like Alaska, where much of the state’s energy is concentrated in a single location, the Railbelt Electrical Grid. Hasquet said she has never seen anything close to a widespread power outage across the entire Railbelt, and that’s largely due to the effectiveness of load shedding.
The “Railbelt” refers to both the area served by the Alaska Railroad and the electrical grid that covers the area. The Railbelt stretches from Fairbanks down to the Kenai Peninsula. About 70% of the state’s population lives in the Railbelt, and 80% of its electricity is consumed there.
“We would never want a situation where there is a power outage across the entire Railbelt,” Hasquet said. “We work every day to prevent such an event, and in my nine years at Chugach, I have never seen anything like this.”
Power outages like the one on Monday are relatively rare. Hasquet estimates that there have been one or two outages per year in recent years. Even if you don’t have to expect them, you can rest assured that when outages occur on the Railbelt, effective measures have been taken to resolve the problem promptly.
Hasquet said the first steps in such a situation would be to bring all customers back online immediately before the investigation begins, both between Chugach and MEA, with a full analysis that could take several weeks.
The exact cause is still unclear.
“We will continue to investigate what the root cause of this was,” Hasquet said. “We will find out what happened internally between our systems and MEA’s; was everything working as it should? And eventually we will find out what actually caused the failure… They flew over the line (on Tuesday), they did not see the cause, but it could have been something that touched the line and then triggered the fault, but we did not see anything visible from the air today when they flew over the line.”
Hasquet added that Monday’s power outage and further outages over the weekend due to heavy rain and storms were a clear sign that more outages are to come and that it is best to be prepared.
“We’re going to have power outages this winter, and so now is the best time for families and individuals to gather their emergency supplies and create a family plan,” Hasquet said. “‘What are we going to do in the event of a power outage or an earthquake or a major event?’ Have those supplies ready so you’re not caught off guard, because the best time to prepare for an emergency is before it happens.”
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