The Invisible Grid Build-out

by Futoshi Tachino

Why this is under-the-radar progress

Everyone talks about how slow it is to build new transmission lines. Less noticed is how much capacity is being freed — right now — on the wires we already have. Three families of “grid-enhancing technologies” (GETs) are scaling fast: (1) advanced reconductoring with modern high-performance conductors that can double capacity within existing rights-of-way; (2) dynamic and ambient-adjusted line ratings (DLR/AAR) that raise safe operating limits based on real weather, not worst-case assumptions; and (3) power-flow control, topology optimization, and other software tools that route power away from bottlenecks to under-used lines. Together, these are connecting more renewables, cutting curtailment and congestion, and buying precious time while big new lines are planned and built [1–3,13–14].

What changed

Reconductoring moved from niche to mainstream.

A peer-reviewed analysis finds that large-scale reconductoring with composite-core conductors can cost-effectively double transmission capacity in existing corridors — often the fastest path to big headroom increases without new towers [2–3]. Real projects report 2× capacity and large loss reductions after replacing legacy ACSR with advanced carbon-core conductors, with no structure changes [14].

Line ratings are getting real-time.

In the U.S., FERC Order 881 requires transmission providers to use Ambient-Adjusted Ratings and accept DLR, with compliance milestones in 2025; market operators are implementing the rule now [4–6]. Europe’s regulators and system operators likewise flag DLR as a quick-to-deploy tool, with typical ampacity gains on the order of 10–15% most of the time and ~20% in documented cases — higher in favorable climates [7–8].

Flow-routing hardware and software are scaling.

Power-flow controllers and topology optimization are being deployed to relieve congestion and raise transfer capability without new lines. National Grid in Britain is rolling out modular power-flow control at multiple substations (projects aimed at unlocking >2 GW of capacity), while operators publish methods to optimize network topology in day-to-day operations [9–11,17]. U.S. regional planners note that interconnection reforms now explicitly consider advanced power-flow control and high-performance conductors in queue processes — pushing GETs from pilot to policy [12–13].

Where it’s showing up

United States.

Utilities are doubling thermal capacity on critical paths via reconductoring, and market operators are phasing in FERC 881’s AAR/DLR requirements in 2025. Case studies report tens of megawatts of generation “freed up,” major loss cuts, and large capex/time savings versus new build [4–6,14].

United Kingdom & Northern Europe.

Britain’s transmission owner is deploying modular power-flow control to reduce bottlenecks and accelerate renewable connections; EU/EEA regulators and TSOs are integrating DLR into operational indicators and planning guidance, with documented ~10–20% capacity gains and rapid deployment timelines [7–11,15].

Planning regions (SPP/MISO and beyond).

Regional studies now include GETs as candidate solutions for increasing transfer capability and clearing interconnection queues; planners are evaluating topology optimization and advanced conductors alongside traditional upgrades [10,12–13,19].

Why it matters

Fast, cheap, scalable headroom.

Reconductoring and DLR can be deployed in months to a couple of years, typically at a fraction of the time and cost of new corridors — yet deliver double-digit to 100%+ capacity gains depending on context [2–3,7–8,16].

Integrates renewables now.

By raising ratings when it’s windy and cool (exactly when wind output peaks), DLR aligns physical capacity with renewable generation profiles — cutting curtailment and easing interconnection backlogs [1,4,8,11].

Stacks with big-build strategies.

GETs complement — not replace — new transmission. They reduce congestion and keep projects moving while long-lead lines, HVDC backbones, and interregional upgrades work through siting and permitting [1–3,13,16].

What to watch next

- Nationwide AAR/DLR operations under FERC 881: how quickly operators shift from static to weather-aware ratings in markets and reliability tools [4–6].

- Mass reconductoring programs using composite-core conductors across congested corridors; look for standardized designs and outage-minimizing methods [2–3,18].

- Portfolio planning with GETs by default in interconnection and long-term transmission plans (e.g., explicit evaluation of power-flow control/topology options before green-lighting expensive rebuilds) [12–13].

- Performance data from UK/EU pilots: measured GW of headroom unlocked, curtailment avoided, and connection dates brought forward by modular power-flow control and DLR [7–11].

Bottom line: We don’t need to wait a decade for every gigawatt of grid capacity. Sensors, software, and smarter wires are quietly turning today’s network into tomorrow’s — doubling capacity on key spans, adding double-digit ratings on windy days, and routing power around bottlenecks. It’s pragmatic, portfolio-based progress that’s already cutting congestion and connecting clean energy at scale [1–3,7–11,13–14].

References

[1] The Brattle Group. Building a Better Grid: How Grid-Enhancing Technologies Complement Transmission Buildouts. April 2023. https://www.brattle.com/wp-content/uploads/2023/04/Building-a-Better-Grid-How-Grid-Enhancing-Technologies-Complement-Transmission-Buildouts.pdf

[2] Chojkiewicz, E., et al. “Accelerating transmission capacity expansion by using advanced conductors.” Proceedings of the National Academy of Sciences (PNAS), 121(45): e2411207121, 2024. https://www.pnas.org/doi/10.1073/pnas.2411207121

[3] GridLab / UC Berkeley (Chojkiewicz, E., et al.). 2035 Report: Reconductoring Technical Report. May 2024. https://www.2035report.com/wp-content/uploads/2024/05/GridLab_2035-Reconductoring-Technical-Report.pdf

[4] Federal Energy Regulatory Commission (FERC). “Presentation: Ambient-Adjusted Ratings for Improved Market Efficiency — Design and Implementation.” July 24, 2024. https://www.ferc.gov/media/presentation-ambient-adjusted-ratings-improved-market-efficiency-design-and-implementation

[5] Utility Dive (T. McKeag). “Meeting the challenge of FERC Order 881: Why open source matters for AAR implementation.” June 13, 2025. https://www.utilitydive.com/news/ferc-order-881-aar-ambient-adjusted-rating-trolie/750604/

[6] California ISO (CAISO). “FERC Order №881 Implementation — Stakeholder Presentation.” April 8, 2025. https://stakeholdercenter.caiso.com/InitiativeDocuments/Presentation%20-%20FERC%20Order%20No.%20881%20Implementati-%20Apr%208%2C%202025.pdf

[7] currENT / Compass Lexecon. Prospects for Innovative Grid Technologies. June 17, 2024. (Includes quantified DLR case: up to ~20% capacity increase; typical 10–15%.) https://www.currenteurope.eu/wp-content/uploads/2024/06/CL-CurrENT-BE-Prospects-for-Innovative-Grid-Technologies-final-report-20240617-1.pdf

[8] WATT Coalition. Unlocking Power Line by Line: Dynamic Line Ratings. November 2024. (Typical U.S. DLR gains; many lines ≥10% extra capacity 90% of the time; 30–50% in favorable climates.) https://watt-transmission.org/wp-content/uploads/2024/11/Unlocking-Power-Line-by-Line-Dynamic-Line-Ratings.pdf

[9] Smart Wires & National Grid (UK). “National Grid and Smart Wires aim to reduce grid bottlenecks through new innovation project.” May 2, 2024. https://www.smartwires.com/2024/05/02/national-grid-and-smart-wires-aim-to-reduce-grid-bottlenecks-through-new-innovation-project/

[10] Smart Wires & National Grid (UK). “National Grid Northern England projects — unlocking over 2 GW.” April 2, 2024. https://www.smartwires.com/2024/04/02/national-grid-northern-england-projects/

[11] The Wall Street Journal. “BP Energy Partners Backs Power Grid-Technology Company Smart Wires.” January 29, 2025. https://www.wsj.com/articles/bp-energy-partners-backs-power-grid-technology-company-smart-wires-20c49bc4

[12] Midcontinent Independent System Operator (MISO). “Advanced Transmission Technologies — ERSC Working Group.” September 27, 2024. (Notes FERC Order 2023 consideration of high-performance conductors and power-flow control in interconnection.) https://cdn.misoenergy.org/20240927%20ERSC%20Working%20Group%20Item%2004%20Advanced%20Transmission%20Technologies650072.pdf

[13] The Brattle Group. Unlocking the Queue with Grid-Enhancing Technologies. February 2021. https://watt-transmission.org/wp-content/uploads/2021/02/Brattle__Unlocking-the-Queue-with-Grid-Enhancing-Technologies__Final-Report_Public-Version.pdf90.pdf

[14] CTC Global. “American Electric Power Doubles Capacity, Saves Time and Money (ACCC Reconductoring Case Study).” Case study page, accessed 4 Nov. 2025. https://ctcglobal.com/aep-reconductoring-case-study/

[15] Agency for the Cooperation of Energy Regulators (ACER). ACER Recommendation 03–2023 (reasoned proposals for network codes; references to DLR monitoring and performance indicators). December 2023. https://www.acer.europa.eu/acer-recommendation-03-2023-reasoned-proposals-amendments-network-codes-requirements-grid-connection-generators-and-demand-connection

[16] U.S. Department of Energy, Office of Electricity. Dynamic Line Rating — Report to Congress. June 2019. https://www.energy.gov/oe/articles/dynamic-line-rating-report-congress-june-2019

[17] AES. Smarter Use of the Dynamic Grid: A Practical Guide to Topology Optimization. April 2024. https://www.aes.com/sites/aes.com/files/2024-04/Smarter-Use-of-the-Dynamic-Grid-Whitepaper.pdf

[18] ISO-NE / CTC Global. “Advanced Reconductoring (materials deck): carbon-core conductor properties and outage-minimizing methods.” June 18, 2025. https://www.iso-ne.com/static-assets/documents/100024/2025_06_18_gets_ctc_global_material.pdf

[19] Southwest Power Pool (SPP). 2024 ITP Assessment Report. January 24, 2025. (Transfer capability and study scope including GETs.) https://www.spp.org/media/2229/2024-itp-assessment-report-v10.pdf

Bio

Futoshi Tachino is an environmental writer who believes in the power of small, positive actions to protect the planet. He writes about the beauty of nature and offers practical tips for everyday sustainability, from reducing waste to conserving energy.