A sensor about the size of a bowling ball can measure the real-time temperature of a transmission line. With this information, the operator can safely increase the level of power flowing through the line.

The technology has grown in popularity in Europe in recent years, while remaining on the fringes of the U.S. market.

Great River Energy, a power provider to rural electric cooperative utilities in Minnesota, is now poised to take the lead in using these tools stateside. This week, it announced the installation of 52 sensors on lines across the state.

The company, which is based near the Twin Cities, decided to use the sensors systemwide following a positive experience with a pilot project in which four of the sensors, made by Heimdall Power of Norway, helped to increase the amount of power that could be delivered on a line by up to 42.8 percent.

That’s an eye-popping number, considering that interstate power line capacity is at a premium and the lack of available capacity is a major choke point hindering the speed of development of renewable energy. Transmission line projects often take a decade or more to build and can have costs in the billions of dollars, so anything that can get more value from existing lines is a boon to the U.S. grid.

As this technology is adopted, the big winners would include wind and solar power plants, especially those in remote areas, which could reduce how often they need to shut off because of a lack of line capacity.

Heimdall, a hardware and software company, says Great River’s order is the largest deployment of this kind of sensor technology to date in the United States. Previously, the largest order was 42 sensors, which a Heimdall competitor, Boston-based LineVision, said last year that it will install for the utility AES in Indiana and Ohio. 

The Heimdall sensor’s official name is the “Neuron” but Heimdall sometimes refers to the product as a “magic ball.” The equipment weighs eight pounds and can be fastened to live power lines using a drone. The sensor runs using electricity it draws from the line.

I reached out to Jørgen Festervoll, Heimdall’s CEO, to better understand how the sensors boost power. He explained that the balls, which fasten to power lines, measure the line’s temperature and broadcast it back to an operator.

One of the key points to understand is that power lines get hotter as their power flow increases. By knowing the precise temperature, the operator knows how close the line is to maxing out on its capacity.

“Think about the temperature on the line as being the speed limit,” Festervoll said in a video call from Oslo. “Without the software and sensor, like the ones Heimdall Power provides, you’re driving without a speedometer.”

Without such sensors, a power company will set limits on the flow of power on a seasonal basis, rather than in response to real-time conditions, which can lead to a lot of unused capacity. By knowing exactly how much power a line can handle, an operator can increase the flow of power for hours or even days to get closer to the limit than otherwise would happen.

Heimdall is one of a growing number of companies, almost all of them less than a decade old, that work on what the power industry calls “grid-enhancing technologies.” Others include Ampacimon of Belgium and LineVision.

Heimdall, founded in 2016, has about 50 employees and customers in 17 countries, mostly in Europe.

RMI, the research and advocacy group, has written about the promise of grid-enhancing technologies and lamented that U.S. utilities have been slow to use these tools. This includes a report last month that looked at how the products could help to improve grid performance for PJM Interconnection, the country’s largest grid region, which runs from New Jersey to Chicago.

Chaz Teplin, who leads RMI’s clean competitive grids team, said “it’s great news” that Great River Energy is implementing line sensors.

RMI has said it costs vastly more to build a new transmission line compared to the cost of implementing grid-enhancing technologies. But it’s important to specify that this is not an either/or proposition, and companies are going to need to build new lines to meet anticipated demand while also making greater use of grid-enhancing technologies, Teplin said. (BloombergNEF has listed $30,000 as a typical price for a line sensor; Heimdall declined to specify its price, but said it’s less than $30,000.)

So why hasn’t this technology caught on in the United States? He said companies sometimes are wary of the complexity of having one more thing to monitor and an additional set of knobs in a control room.

But he thinks the leading factor is that the utility business model places a premium on building and maintaining large assets. Most utilities make money through a regulated process in which they can charge customers to cover costs plus a guaranteed profit.

“Utilities often don’t have much of a financial incentive to do these really low-cost investments,” Teplin said. “So something that provides a lot of value, if it’s not very capital intensive, doesn’t actually help them with their bottom line.”

He said it’s the job of regulators and regional grid managers to fix what is an unhelpful “misalignment of financial incentives.”

I asked him if the 42.8 percent gains that Heimdall obtained in Minnesota was in line with what he’s seen elsewhere. (To understand what this percentage means, if a line has a typical capacity of about 1 gigawatt, the sensor is showing that the line can safely carry about 1.4 gigawatts.)

Teplin pointed me to an appendix to last month’s report that showed the improvement that the authors recorded in PJM territory using line sensors. The gains varied significantly based on the time of day and the month, from lows that were in the low single digits during overnight hours in November, to highs of more than 30 percent in April.

The variables that led to the disparities included the air temperature and the level of wind. A low air temperature and high wind helped to cool the lines, and cooler lines meant they had additional power capacity.

My takeaway was that 42.8 percent improvement is possible but should be viewed as the high end of what’s to be expected. Also, the amount of change varies a lot even on the same line, so the use of sensors means being able to increase the level of power sometimes, but not all the time.

It’s pretty simple who benefits from the large-scale use of this technology.

First, wind and solar plant operators would have the equivalent of new lanes of traffic being opened to them on highways that otherwise would be congested. These plants would have priority to use the newfound capacity because they are usually the least expensive resources. An increase in the availability of wind and solar would lead to less demand for more expensive power sources, including coal.

But the big beneficiaries would be utility ratepayers. If grid operators can facilitate the delivery of more wind and solar without building new lines, the result is likely going to reduce electricity costs

“It’s going to save customers money,” Teplin said.

Other stories about the energy transition to take note of this week:

Vehicle Carbon Pollution Would Be Cut, But More Slowly, Under New Biden Rule: Foreseeing a slower U.S. switch to fully electric vehicles than envisioned a year ago, President Joe Biden’s administration has finalized tailpipe pollution standards that it says will cut carbon emissions from new passenger vehicles by more than half by 2032. The rule calls for a more gradual reduction in emissions than the administration had previously proposed, but it’s still Biden’s most consequential executive action on climate change, as my colleague Marianne Lavelle reports for ICN. Major environmental groups were mostly supportive of the change, which comes in the face of pushback from auto manufacturers, dealers and the UAW.

Bill Gates’ TerraPower Ready to Build New U.S. Nuclear Power Plant: Chris Levesque, the CEO of TerraPower, has said the company will begin construction of its first nuclear power plant in June in Kemmerer, Wyoming, as Darrell Proctor reports for Power Magazine. The comments from Levesque will be greeted as great news by advocates for nuclear power who have high hopes for TerraPower’s Natrium reactor technology, one of several small modular reactor designs that could be part of a new generation of nuclear plants. Microsoft co-founder Bill Gates is a major investor in TerraPower and his comments about his high hopes for the technology have received extensive media coverage. So far, the development of small modular reactors has been marked by high costs and delays in construction, like NuScale’s decision in November to cancel its plan to build a plant in Utah.

The Federal Government Releases a Road Map for Increasing Geothermal Power: A new Department of Energy report says the use of geothermal energy could increase twentyfold in the United States by 2050 and provide a clean alternative to fossil fuel power, as Jason Plautz reports for E&E News. The government has several projects underway to expand the use of geothermal energy, and startups such as Fervo Energy also are working to develop geothermal power plants. A geothermal power plant taps into the earth’s heat to produce electricity. Recent advancements in technology use oil-drilling techniques to expand where geothermal plants can be built.

Data Centers, Bitcoin and EVs Send Utilities Scrambling for More Power: After more than 30 years of falling or flat demand for electricity, utilities are forecasting a rapid increase in the country’s needs, as Kristi Swartz and Pam Radtke report for Floodlight. Utilities have been caught off guard by projected increases in electricity demand to serve data centers and EV infrastructure and to mine for cryptocurrencies like Bitcoin. In response, the companies are proposing, or are likely to propose, a big increase in power plant construction, including plants that run on natural gas and could harm the country’s push to reduce emissions from the electricity sector.

Inside Clean Energy is ICN’s weekly bulletin of news and analysis about the energy transition. Send news tips and questions to [email protected].