The North American power grid is often referred to as “the world’s largest machine.” What may appear to be a haphazard collection of power plants and lines is actually an interconnected, highly engineered system of three networks stretching millions of miles across southern Canada and the continental United States. Its operators perform miracles every day, instantaneously connecting electricity supply from thousands of power plants with the demands of over 400 million people. Amazingly, this machine is 99.95% reliable; the average U.S. customer loses power only twice a year for a total of five hours.
However, 70% of the grid is over 50 years old, and it’s being tested in unprecedented ways. The American Society of Power Engineers gave the U.S. grid a grade of C- in its 2021 report card. Energy demand is growing for the first time in decades, spurred by resurgent manufacturing (much of which was spurred by investments in the Inflation Reduction Act), rapacious data center growth (largely due to artificial intelligence), and nascent electrification of industries once built on fossil fuels, such as the shift from gas-powered cars to electric vehicles. Meanwhile, increasingly frequent and severe extreme weather events have battered the grid in recent years, costing consumers billions in extra energy expenses.
To safely and affordably meet increased electricity demand while decarbonizing the grid, we must build new high-voltage long-distance transmission lines (HVTLs). But this won’t happen overnight: New HVTLs take an average of 10 years to build and cost an average of $1 million per mile. Meanwhile, electricity customers nationwide paid $11.5 billion in congestion costs in 2023 — nearly double the amount they paid in 2020. Congestion occurs when there is not enough transmission capacity to deliver the cheapest sources of electricity, and higher-cost resources must be dispatched instead to meet demand.
The U.S. power grid needs help. Advanced transmission technologies are an important part of the solution.
What Are Advanced Transmission Technologies?
Advanced transmission technologies are a promising set of tools that can be used to quickly and cheaply expand the capacity and improve the operation of the existing grid. The category includes both grid enhancing technologies that can be installed on top of the existing grid, as well as advanced conductors that can replace and increase the capacity of existing lines. These technologies are well-tested and have already been widely deployed across the world.
Despite their “advanced” label, many advanced transmission technologies are surprisingly simple in concept. Take improvements to the line ratings for example: To limit the risk of overheating, transmission lines have historically been rated “statically,” meaning they only transmit power up to a threshold, conservatively set to be safe under the hottest conditions (when lines are unable to carry as much power as when it’s cooler).
However, colder temperatures and higher winds actively cool transmission lines and therefore allow them to safely carry more power than their static line rating would suggest. This means that almost all statically-rated lines could be transmitting at least 10% more capacity 90% of the time. When simple sensors are installed, new “dynamic” line ratings (DLRs) can be adjusted in real time as wind and temperature shifts, allowing around 30% to 50% more power to be transmitted in favorable climates.
Other advanced transmission technologies use complex technologies to improve grid efficiency. For example, advanced power flow control devices (APFCs) allow grid operators to control how power is flowing across the grid by changing the resistances of different power pathways. Electricity, like water, flows along the path of least resistance. Building on this analogy, The WATT Coalition describes APFCs as “partial dams” which can be used to redirect “water” (power) across different channels, ensuring that more of the grid is used efficiently. APFCs boost overall system capacity and reduce congestion costs.
What Are the Benefits to Scaling Advanced Transmission Technologies?
Perhaps the greatest advantage of advanced transmission technologies is that they can be deployed in a fraction of the time it takes to build new transmission lines. On the shorter end, DLR projects take an average of only three months to complete. Even more ambitious projects, like converting a line so that it transports direct current power instead of alternating current power, can triple the capacity of an existing line in half the time it takes to build a new line.
Secondly, advanced transmission technologies are cheaper to build than new transmission lines and unlock far more economic benefits than costs. Upgrading transmission lines with new, higher capacity advanced conductors can provide similar gains in capacity compared with building new transmission lines, yet they can be anywhere from five to 10 times cheaper per-mile. Grid enhancing technologies like DLR can provide an even greater cost-benefit return. In 2018, the Midwestern utility AEP spent $500,000 to install DLR on 25 miles of its lines. In only 10 months of monitoring, the system saved more than $15 million in congestion costs, providing a whopping 30 to 1 benefit-cost ratio in less than a year of operation.
Finally, advanced transmission technologies can improve reliability and public safety by reducing the likelihood of grid failures and wildfires. Take DLR, for example: On our warming planet, temperatures may sometimes be hotter than the ones used to conservatively set static line ratings. Whereas static lines will maintain line current even in high heat, lines with DLR will sense the extreme weather and lower current, reducing the risk of the line sagging into vegetation and igniting a fire. Advanced conductors also mitigate wildfire risk by reducing sag, while APFC systems can help quickly deenergize parts of the grid when needed.
Though the study of advanced transmission technologies for wildfire mitigation is an emerging field, governments are already recognizing their potential. For example, Utah’s recently passed HB 212 directs utilities to study advanced transmission technologies for their wildfire mitigation potential as part of the utilities’ integrated resource plans.
What Progress Is Being Made to Implement Advanced Transmission Technologies?
Hundreds of utilities have already deployed advanced transmission technologies successfully in the U.S. Survey studies compiled by the Idaho National Laboratory for grid enhancing technologies and advanced conductors attest to their high benefit-cost ratios, ease of implementation and quick payback periods. To date, most of the advanced transmission technology projects undertaken by U.S. utilities have been voluntary and limited in scope. However, there are hopeful signs that U.S. policymakers are beginning to recognize the potential of advanced transmission technologies to meet our grid challenges quickly and cost-effectively and will enact legislation to make them more widespread.
Policy activity on advanced transmission technologies has been particularly robust at the state level. Since 2023, more than 10 states governed by both Republicans and Democrats have adopted advanced transmission technology legislation. Proving momentum, in 2025 alone, 17 states saw the introduction of related bills. These bills primarily work by requiring utilities and other transmission owners to study advanced transmission technologies as alternatives to building new lines. For example, South Carolina’s recently passed H 3309 requires utilities to assess advanced transmission technologies as solutions for transmission needs within their integrated resource planning process.
Activity at the national level is happening as well. The Federal Energy Regulatory Commission (FERC) issued an advanced notice of proposed rulemaking (ANOPR) last June that included a framework for requiring DLR on transmission lines. This has received broad support in comments from consumer advocate groups, utilities and grid operators. Supporters of a DLR requirement argue that such a regulation is necessary to secure “just and reasonable” electricity rates — core to FERC’s mandate — because of the cost savings that DLR unlocks for consumers.
What Are the Major Barriers to Deployment and How Can We Overcome Them?
Advanced transmission technologies have not been widely deployed in the U.S., and many utilities, regulators, policymakers and consumers remain unaware of their benefits. Requirements to study advanced transmission technologies in utility proceedings such as integrated resource plans and (including those recently passed by Indiana and Ohio) will help to raise awareness of their benefits while giving advocates greater leverage to push for their adoption. and Ohio) will help to raise awareness of their benefits while giving advocates greater leverage to push for their adoption.
Governors can also work to encourage adoption. In 2023, Massachusetts Governor Maura Healey convened a working group to study advanced transmission technologies and make recommendations for their adoption in New England. Governors can also include them in their budget requests, as New Mexico Governor Michelle Lujan Grisham did in the 2026 budget by calling for a $1 million grid modernization grant program.
Ironically, the low costs of advanced transmission technologies, which make them such promising tools to quickly meet grid challenges, are also a barrier to their implementation. Simply put, they don’t make utilities as much money. Under traditional “cost of service” business models, regulated utilities are allowed to recover their capital costs plus an allowed rate of return through electricity prices.
As several advocates have pointed out, this incentive structure means that utilities can make more money by pursuing capital-intensive projects like new transmission lines over cheaper advanced transmission technology projects. Furthermore, these projects are not yet eligible for cost recovery in some states, meaning utilities aren’t able to profit from deploying advanced transmission technologies. Things are slowly changing, however; recent bills passed in Montana, New Mexico, Utah and Indiana have authorized cost recovery for these technologies.
Reforming outdated business models should be considered to spur adoption. One such proposal called “shared savings” would allow utilities to recoup some of the savings that result from projects in their electricity rates. Another policy idea, called performance-based ratemaking, would tie utility profits to meeting certain performance targets that incentivize advanced transmission technologies — for example, a target to increase the amount of power a utility can carry on its existing system. Finally, shifting from incentivizing to explicitly requiring utilities to deploy advanced transmission technologies in the public interest, as FERC did with the DLR ANOPR, is another way to deploy these technologies at scale.
A Critical Investment
At a time when customers face rising energy bills and terawatts of clean energy languish in queues to interconnect to the grid because of a lack of grid capacity, advanced transmission technologies represent our best hope for quickly and cost-effectively reducing the pressure on our grid. These technologies are essential complements to new lines and must at least be considered by utilities and regulators when they review proposals to increase transmission capacity.
In the U.S., momentum is growing to deploy advanced transmission technologies at scale, and an abundance of evidence shows that these technologies are safe, effective and affordable. Let us build on this momentum to secure the prosperous clean energy future we all deserve.
WRI’s Ian Goldsmith contributed to this report.