Aging US transmission lines, if not replaced, threaten grid reliability, national security, and economic competitiveness, creating an urgent need for modernization, resilience, and interregional upgrades.
The United States is quietly approaching a major inflection point in its infrastructure story: much of its electric transmission grid is entering old age.
Power lines crisscrossing the country rarely make headlines, and yet this strategic backbone of the US energy system underpins our economic and defense leadership in the world as the foundation of our nation’s critical infrastructure. It supports every means of economic production for everything we have in society, from the food we eat to the healthcare we receive, how we communicate, and even our ability to defend the nation. But many of these lines are over 25 years old—and an increasing share are 40 to 50 years old or more.
This aging infrastructure poses a mounting threat to the reliability, security, and scalability of America’s electricity system at a time of unprecedented stress and transformation. Transmission is a strategic asset underpinning US economic and defense leadership. Yet unless we confront the aging of the system, that strategic asset risks becoming a strategic vulnerability—one that could undermine the very industries, communities, and military capabilities it was built to support.
Many Americans are surprised to learn that some high-voltage transmission lines—critical for delivering electricity across vast distances—were installed before personal computers were common. And while 25 years doesn’t automatically rendera line unsafe, it often marks the beginning of accelerated maintenance needs, increased operational risks, higher maintenance costs, and a narrowing window for proactive upgrades. ISO-New England notes that while some facilities over 40-50 years old remain functional, others fail in under 20 years due to material degradation and environmental factors. Meanwhile, many US lines built in the 1950s and 1960s have reached or exceeded their original 50-year design life.
What Happens After 25 Years?
Transmission lines, like bridges and roads, have a design life. Most high-voltage lines are engineered for 30 to 50 years of service. After 25 years, key components, such as conductors, insulators, and steel towers, begin to show signs of wear. Environmental exposure degrades materials. Metal fatigue can cause conductor sag, and corrosion of tower foundations can accelerate. These are not theoretical concerns: they’re the daily reality for utilities tasked with maintaining assets built decades ago.
According to the Grid Strategies 2025 report, the United States is now in a full-fledged reinvestment cycle. Many transmission assets are long past their prime, yet still in operation due to permitting delays and funding constraints. The consequences of deferring modernization are not simply technical—they’re economic and human.
Why It Matters More Than Ever
This isn’t just about old wires. America’s electric grid is facing an unprecedented convergence of pressures. Demand for electricity is rising sharply due to the electrification of transportation, the growth of AI-powered data centers, and efforts to bring industrial manufacturing back to the United States. These trends all require a stable and high-capacity transmission backbone.
As my last piece inThe National Interest pointed out, large-scale transmission is not merely a utility issue; it’s a national security imperative. The ability to move power from generation sources to demand centers underpins economic competitiveness and military readiness alike. And when lines are outdated or insufficient, bottlenecks, blackouts, and costly market distortions follow.
A CSIS report on transmission in the AI age emphasizes that data centers in places like Virginia are already straining the limits of local capacity. Without rapid transmission expansion and modernization, the economic opportunity presented by next-gen industries could be undermined by infrastructure failures rooted in decisions made—or delayed—decades ago. Many studies show that for every dollar invested in energy infrastructure improvements, between $3 and $7 is returned to rate-paying consumers. In the case of Texas, the Electric Reliability Council of Texas’s (ERCOT) Competitive Renewable Energy Zone (CREZ) projects are estimated to return $78 billion in consumer benefits on a $6.9 billion investment.
The Real-World Risks of Aging Infrastructure
We don’t need to imagine what happens when old lines fail. California has become a case study in the risks of neglect. Investigations found that aging equipment operated by Pacific Gas & Electric (PG&E) sparked multiple catastrophic wildfires, including the deadly Camp Fire in 2018. Some of the implicated lines were over 80 years old.
In Texas, the 2021 Winter Storm Uri exposed how fragile and overloaded parts of the grid had become. While transmission lines weren’t the only failure point, the lack of modern, flexible interregional connections left operators unable to import power when they needed it most. In December 2022, while Winter Storm Elliott forced rolling blackouts across large parts of the South, cheap power in the Plains states was actively curtailed because of oversupply. Interregional transmission ties between the South and Midwest would have prevented blackouts, saved billions, and protected life.
The problem isn’t limited to high-profile disasters. According to a 2024 NERC Interregional Transfer Capability Study, many regions across the United States lack adequate transfer capability to ensure reliability during extreme weather or grid emergencies. Much of the existing infrastructure was designed for a generation with radically different demand profiles and climate expectations.
Why Replacing Lines Is So Hard
Given the stakes, why hasn’t the grid been rebuilt? The answer lies in a mix of policy, permitting, and market dynamics. Unlike roads or airports, high-voltage transmission lines often cross multiple jurisdictions, each with its own approval process. It can take 7 to 10 years to permit and build a new line.
Utilities may also defer replacement due to uncertain cost recovery. With state regulators focused on keeping rates low, the incentives to invest in proactive modernization are weak unless federal support or mandates exist.
Finally, there’s the issue of coordination. Without a national transmission planning framework, utilities often pursue local optimizations rather than regional or interregional upgrades. This fragmented approach slows progress and increases overall system costs.
What Needs to Change
First, asset management must become more proactive. As lines enter their third decade of service, utilities should implement regular inspections, digital monitoring, and prioritize replacement or reinforcement—not just patched as they fail.
Second, Congress and the Federal Energy Regulatory Commission (FERC) should continue pushing for streamlined permitting for replacement projects, particularly those that upgrade capacity without requiring entirely new corridors. Recent Department of Energy (DOE) efforts to support transmission buildout must be matched by regulatory reform that eases the burden on the companies carrying out projects and supports an environment conducive to timely upgrades.
Third, utilities should deploy Grid-Enhancing Technologies (GETs)—such as dynamic line rating and advanced power flow controls—that can increase the capacity and monitoring of existing infrastructure while longer-term solutions are built. Recent natural disasters—like the fires in California, and the Texas outages—show that proactive inspection and GETs are not optional considerations, but necessary for resilience.
Conclusion
Aging transmission lines represent a significant risk factor that must be addressed for transmission to support economic security. Once infrastructure reaches 25 years, it enters a phase where performance, safety, and economic efficiency begin to degrade. With a national grid that was largely built in the mid-to-late twentieth century, America faces a choice: reinvest boldly in resilience or suffer the consequences of an outdated backbone increasingly vulnerable to disaster.
This is not an engineering challenge—it’s a leadership and government one at every level, from federal to municipal. Rebuilding trust in the grid means rebuilding the grid itself, which is an effort that the industry is more than well prepared and capable of doing. However, it must begin with leaders and policy makers acknowledging that transmission, particularly interregional transmission capabilities, cannot support a twenty-first-century economy if it’s stuck in the twentieth century, and progress must be championed rather than challenged across every jurisdiction. In an era of rapid technological change, America’s policymakers are at an inflection point: allow an aging grid to throttle a twenty-first-century economy or assist in building a backbone strong enough to power growth, security, and resilience for generations.
About the Author: Fred Bailey
Fred Bailey is a cybersecurity and national security leader with over 20 years of experience in protecting critical infrastructure and securing the US energy landscape. He has directed strategies countering nation-state threats across the energy, transportation, and communications sectors. A US Army veteran, Fred recently retired from federal service where he has led intelligence operations, risk mitigation, and resilience planning for Homeland Security to safeguard industrial and energy supply chains, ensuring both economic security and national defense readiness.
Image:Black_Kira/shutterstock
