The North American power grid supplies electricity to over 400 million people, making it the world’s largest interconnected power network.
Often described as the “largest machine on Earth,” the US grid consists of millions of miles of transmission lines and thousands of utilities. Rather than operating as a single system, it is divided into several wide-area synchronous grids — the Western, Eastern, and Texas Interconnections — as well as the Quebec and Alaska Interconnections.
According to Aaron Bloom, Executive Director of NextEra Energy Transmission, the US lacks a centralized approach to microgrid planning and interconnection, especially when compared to the European Union and China. This limitation makes transferring power between regions challenging.
Compounding the issue, many of the country’s transmission lines are decades old and cannot accommodate high-voltage direct current (HVDC) transmission, which is critical to meeting future energy demand.
An aging grid under increasing demand
The World Resources Institute (WRI) report, “How Advanced Transmission Technologies Can Revamp the Aging US Power Grid,” underscores that while the grid remains nearly 100% reliable, 70% of its infrastructure is more than 50 years old.
Meanwhile, electricity demand continues to climb — driven by booming data center growth, the rise of electric vehicles, and a resurgence in domestic manufacturing.
This raises an urgent question: How can the US meet rising energy needs with an outdated grid? Building new high-voltage long-distance transmission lines is one solution, but it is both time-consuming and costly, averaging 10 years to construct and around $1 million per mile.
Advanced transmission technologies: A faster, cheaper solution
The WRI highlights advanced transmission technologies—including grid-enhancing technologies (GETs) and advanced conductors—as cost-effective ways to increase grid capacity without waiting a decade for new infrastructure.
For example, dynamic line ratings (DLRs) use real-time temperature sensors to adjust line capacity dynamically, boosting power transmission by 30% to 50%.
Similarly, upgrading existing transmission lines with advanced conductors can provide a comparable increase in capacity at a cost per mile that is 5 to 10 times lower than building new ones.
Beyond cost savings, these technologies also enhance grid reliability and safety. DLRs can detect extreme heat conditions and automatically lower current flow, reducing the risk of wildfires and preventing grid failures — something static line ratings cannot do.
Overcoming barriers and building momentum
Despite growing interest, two significant barriers limit widespread adoption:
- Lack of awareness about the benefits of advanced transmission technologies.
- Outdated business models that incentivize high-capital projects over cost-effective upgrades.
Momentum, however, is building. Since 2023, more than 10 states have enacted legislation supporting advanced transmission technologies. In 2025 alone, 17 additional states introduced bills promoting GETs.
At the national level, the Federal Energy Regulatory Commission (FERC) issued an Advanced Notice of Proposed Rulemaking (ANOPR) in June 2024, outlining a framework to require DLRs on transmission lines.
Building a smarter, more resilient power grid
The US power grid may be vast and reliable, but its aging infrastructure and fragmented design hinder its ability to meet soaring electricity demand.
While new transmission projects remain part of the solution, advanced transmission technologies present a more immediate, affordable path forward.
By scaling up investments in DLRs, advanced conductors, and other innovations, the US can strengthen its grid, boost capacity, and ensure a cleaner, more resilient energy future.
Sources:
Hack, J. (2025, July 10). How Advanced Transmission Technologies Can Revamp the Aging US Power Grid. World Resources Institute. Retrieved from https://www.wri.org/insights/advanced-transmission-technologies-us-power-grid?
Skok, P. (2024, September 18). Inside the world’s largest interconnected grid. Dgplusdesign. Retrieved from https://www.dgplusdesign.com/insights/inside-the-worlds-largest-interconnected-grid
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