Minnesota utilities deploy 'magic balls' to help clean energy transition
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A high-tech device about the size of a bowling ball, that latches on to electric transmission lines and looks like Pac-Man, could provide a much-needed jolt to efforts to deliver more wind and solar energy to the power grid. And two Minnesota utilities are leading the charge.
Known colloquially as “smart sensors” — or “magic balls” — the devices collect real-time data from transmission lines, such as air temperature, wind speed and current voltage. Those are all factors that impact how much electricity can safely travel through a power line.
Artificial intelligence then helps process that data to pinpoint the real-time carrying capacity of a specific power line. These “magic balls,” it turns out, can dramatically increase the amount of power running through transmission lines, unlocking a huge amount of unused energy capacity.
"We're able to see, so far through our testing, an annual average of up to 60 percent more capacity on certain transmission lines that we have,” said Priti Patel, who manages transmission for Great River Energy, which supplies electricity to more than two dozen electricity cooperatives across much of greater Minnesota.
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Two years ago, the utility installed about 50 of the sensors on some of its power lines with the most limited capacity. At the time, it was the largest installation of the technology — known in the industry as “dynamic line rating” — in the country.
"That increase in capacity that we now have real-time awareness of allows more low-cost generation to get onto the transmission system and be delivered to homes and farms and businesses, and that results in reduced cost to our members,” Patel added.
It could also play a significant role around the state and country as demand for electricity soars, driven by the boom in data center construction, the growing popularity of electric vehicles, a growth in manufacturing and other factors.
To accommodate that growing thirst for power — and to reduce greenhouse gas emissions — utilities are rapidly building wind and solar farms and a web of new transmission lines. But that can take years and cost billions of dollars, and those efforts often meet community opposition, too. Many newly built clean energy projects have been forced to sit idle because their developers were unable to connect to the congested power grid.
That’s where smart sensors and other alternative transmission technologies can play a critical role, by quickly squeezing more electricity through existing power lines.
"And that's really huge at a time where it's really expensive and hard to expand the grid, but we really desperately need to,” said Sarah Toth Kotwis with the Rocky Mountain Institute, which works to accelerate the clean energy transition. “This is the perfect technology that fills that hole."
Smart power lines
In late February, crews with Duluth-based utility Minnesota Power and the Norwegian firm Heimdall launched a drone into the air along a power line about 40 miles south of Duluth, holding one of the silver smart sensors Heimdall calls “neurons.”
The drone rose up and hovered next to the line. Then the ball opened, like Pac-Man from the vintage video game. Its mouth closed tight over the line, latching the device to it, and the drone released it before descending to the ground. The whole operation took just a couple minutes. Unlike when repairs to a power line are needed, the utility didn’t have to reroute electricity elsewhere.
"One of the cool things with this program is these line sensors are very inexpensive to install,” said Dan Gunderson, vice president of transmission and operations planning for Minnesota Power, which installed 52 of the sensors on six of its most congested power lines this winter.
“This is one of the most practical, cost-effective ways to make our grid stronger and more flexible,” Gunderson said, while also helping Minnesota reach its target of generating 100 percent of its electricity from carbon-free sources by 2040.
Here’s why experts say this technology has so much potential. Every power line has a maximum capacity, but utilities limit how much electricity they send through them, because the more power there is running through the line, the hotter it gets. And as the line gets hotter, it expands, and sags. If it gets too hot, it could damage the line.
As a result, utilities tend to operate their lines far below capacity. They typically set capacity limits on a seasonal basis.
“And traditionally, that's based on the hottest day of the year,” said Brian Berry, chief product officer for Heimdall Power. “But in reality, weather is a lot different. There's normally a bit of wind on power lines. It's normally not the hottest day of the year,” Berry said
He says even a very light breeze can have a huge impact by cooling the line, allowing for significantly more power to be transported. But without a sensor on the line, it’s impossible to know the exact wind speed at that spot and the impact it’s having on the line.
“When you measure, you don't have to be conservative anymore. As you have cold days or slightly windy days, you can really get a lot out of that line. We can drive that system a lot closer because we know exactly how far to the edge we are,” said Berry.
“We're able to take these relatively dumb pieces of metal in the air and make them smart.”
The data is communicated via cellular and satellite. Then, Heimdall's software uses machine learning to crunch that data to figure out precisely how much power can safely be transported over the line.
Minnesota Power plans to use the technology to increase the amount of power it can deliver over its existing lines as it expands its transmission system over the next few years.
“The more we can get out of the existing system as we're taking lines out of service and doing construction, the better off we are from a customer cost perspective.”
Indeed, studies have found the technology could save consumers a huge amount of money. A recent report from the Rocky Mountain Institute found that investing about $100 million in “smart sensors” and similar grid-enhancing technologies in five eastern states could allow for a huge amount of new generation capacity to connect to the grid and save ratepayers about $1 billion per year.
“Which is a huge number,” said the Institute’s Toth Kotwis. “We're leaving efficiency on the table, and unfortunately, consumers are paying that price.”
The technology is widely used in Europe, but it's been slow to take hold in the U.S. Heimdall has installed about 300 of its neurons in the Midwest. A third of those are in Minnesota through the Great River Energy and Minnesota Power projects.
“Minnesota really leads the way on this,” said Heimdall’s Berry. “We love working with forward-thinking utilities. Sometimes the regulatory environment doesn't actually encourage this type of innovative thinking.”
Experts say that's partly because regulated utilities earn a guaranteed return on investment by building large, capital-intensive infrastructure projects such as power plants and transmission lines. There’s often little incentive to invest in low-cost solutions.
"We do still need more big transmission infrastructure, but it also prevents them from looking at small and very cost-effective measures that could help in the near term,” said Toth Kotwis. “And it really is up to regulators to kind of fix those disincentives.”
Minnesota lawmakers took a step in that direction two years ago, when they passed a bill requiring large utilities to evaluate grid enhancing technologies like “magic balls” on highly congested power lines.
State Rep. Larry Kraft, DFL-St. Louis Park, sponsored the bill, one of the first such laws in the country. He believes utilities around the state genuinely care about providing affordable energy.
“But if you look at just how the system is set up, what it encourages, these kinds of solutions are absolutely under-invested, just because of how our regulatory structure is.”
