CDOT is working to minimize power outages that lead to closures at the Eisenhower Tunnel
Two power outages in 2021 led to lengthy closures at the Eisenhower-Johnson Memorial Tunnels, backing up traffic for miles on both sides and throughout the northern end of Summit County.
The Colorado Department of Transportation has made upgrades to minimize outages like this, and despite some issues along the way, it’s getting closer to having backups in place to avoid an extended closure.
Power comes into the tunnel from both sides of the Continental Divide, so if one side fails, the tunnel can be fully powered from the other side. This system was recently upgraded from analog to digital, meaning instead of someone at the tunnel needing to physically switch the power source, it can now be done automatically.
“We’re kind of working out the bugs to automatically transfer that power, because in the past, an employee would have to physically switch levers over and transfer the power,” said Neal Retzer, one of CDOT’s lead engineers at the tunnel. “All the original technology up there is all analog, meaning you physically have to transfer power.”
Retzer said there have been some growing pains converting to the new system, and an issue with the automatic switch is what led to the outage Aug. 14, 2021. Retzer said crews were in the process of fully making the switch when this 20-minute outage occurred. He said he thinks the system worked properly in switching the power from one side when the outage started, but it didn’t switch back over properly.
For the outage Dec. 12, 2021, Retzer said the switch did everything it was supposed to do, but something else went wrong.
“It wasn’t just an outage. It might have been like a surge before the outage. … But the fail-safe is that if the equipment up there does not like what it’s seeing, it shuts itself off, and it waits for a human to come back to it and … turn it back on,” Retzer said. “That equipment is designed to do that to protect employees up there, as well as protect itself, because if there’s some really wonky stuff going on with the power, … I mean we have 25,000 volts coming to the facility. Some of that equipment can actually shoot the equivalent of lighting on it.”
Retzer said these were the only two extended power outages the tunnel saw in 2021, but outages at the tunnel are more common than most might realize. He said this is because when there is an outage, the system typically functions properly and transfers power from the alternate side, and nothing in the tunnel is impacted.
Frisco resident Bill Acuff, who used to work at the tunnel for CDOT for about five years, raised concerns about the two outages in 2021.
“In the entire time that I worked at the tunnel, there was only one time when the power went out, and there was an extended outage, and by that, I mean several hours,” Acuff said. “The tunnel was designed to never be without power for any period of time.”
Acuff said that in his experience, it shouldn’t take more than five or 10 minutes to manually switch the power over from one side to the other. He said during the August outage, he was getting calls from friends stuck on the highway asking if he had any idea what was going on.
“If you put an automatic system in to switch the power instead of doing it manually and that fails, the tunnels still shouldn’t shut down,” Acuff said.
As the tunnel continues to age, more work to upgrade its infrastructure is becoming necessary. Retzer said CDOT prioritizes safety for travelers going through the tunnel and its employees. Currently, the bigger issue the tunnels have is a roof leak on the west side that’s letting water get through to some electrical equipment.
Other than that, Retzer said crews are working on getting a new generator for the west side of the tunnel that will replace two of the original generators from when the tunnels were being completed in the 1970s. He said the original generators can’t live up to modern-day demands.
“Right now, those are extremely underpowered,” Retzer said. “Those generators will run every seventh light in the tunnel, and they will run one of our 28 fans on low speed.
“What this new generator will do is, it’ll run every light, it’ll run everything like business as usual. Plus, it’ll give us the ability to run four of our 20 fans on high speed, which is exactly what we need in an emergency event to exhaust smoke.”
Retzer said he expects the new generator to be installed before 2024, and it will mean business as usual if the power goes out on both sides of the tunnel, which is extremely rare. The most recent time Retzer could remember that happening was during the historic avalanche cycle in March 2019.
CDOT spokesperson Presley Fowler said she’s heard engineers at the tunnel explain how isolated its power system is, like being on the end of two 10-mile extension cords.
Last week, the tunnel had some intermittent closures overnight so work could be done to upgrade the tunnel’s power systems. Retzer said this involved a 480-volt motor control center, which will put the tunnels’ fans on a new variable frequency drive as opposed to a simple on-off switch.
“It’s like a dial to turn those fans up, but it’s more intelligent than that,” Retzer said. “It knows how to bring itself up to speed without blowing something up on it.”
Whenever CDOT is doing a big electrical project at the tunnel, Retzer said they try to tackle a bunch of smaller issues, as well. Last week, crews added some finishing touches on the analog to digital system conversion.
“When you have a link in your chain for electric work, it’s digital, digital, and then you have this piece of analog equipment like a breaker. It makes all the digital stuff basically analog,” Retzer said. “You have a weak link in your chain. So that last piece was making every link in the chain digital for that entire connection.”
Retzer said the automatic switch and generator upgrades are the first two pieces to ensure extended outages don’t happen. Beyond that and some other smaller changes to protect their equipment, Retzer said the power lies in the hands of Xcel Energy.
Xcel did not immediately respond to a request for comment.
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