Employees collaborate on North Shore resiliency

Reliable electric service is critical along the North Shore of the Arrowhead Region, not only to keep the TV on or the internet working, but also to power the lights, heat and basic needs of many Minnesotans. This is particularly true on the coldest nights of winter as many Arrowhead Cooperative members use electric storage heating to keep their homes warm.

But because the transmission system that serves the area is a 50-mile, 69-kilovolt radial transmission line with no secondary source or back-up, that prized reliability is at greater risk than most areas of Great River Energy’s transmission system. An outage on the line would have left many members without power until the problem was identified and corrected.

Great River Energy built an emergency generation station at the end of the line in 2008 to support the transmission system during outages. But electric use on the system has since grown, and the emergency generation is now short by 6 megawatts during times of peak electricity use.

North Shore infographicDue to these concerns, Arrowhead Cooperative asked Great River Energy last winter to address this concern. This led to the creation of a cross-divisional Great River Energy and member-owner cooperative team, which was charged with finding a solution fast.

“The team approached the problem from a resiliency standpoint – how do we ensure the system can bounce back from a significant outage,” said Gordon Pietsch, Great River Energy’s director of transmission planning and operations.

He said traditional thinking would have led to building new transmission, but in this case the necessary upgrades would have required an investment of approximately $35 million – not a logical solution given the timeframe to resolve the issue. Instead, by analyzing the problem from different perspectives, the team came up with something Great River Energy and its member-owners can be thankful for: A multi-faceted solution requiring an investment of $1 million to $1.5 million.

The solution included leveraging the existing emergency generation, using load control to reduce peaks and adding motor operated switches along the line that enables Great River Energy’s system operators to remotely operate the switches and speed restoration.

According to Eric Messerich, senior planning engineer on the project, Great River Energy and other transmission providers are seeing more pressure for such “non-wires alternatives” to be considered now that the public and regulators know options like distributed generation, load control and other new technologies can be used to solve problems that in the past could only have been solved with transmission upgrades.

“We’ve begun to look at other technologies. In the past, we had a very baseload and binary system, and now we’re looking more at intermittent solutions and evaluating how much time outages will take to fix,” he said. “The type of process we used to develop the Arrowhead Cooperative recommendation is becoming more warranted.”