Getting Alternative Transmission Technologies to Scale

This report by RMI examines the potential of advanced transmission technologies (ATTs)—comprising grid-enhancing technologies (GETs) and advanced conductors—to expand electricity grid capacity and reliability. While pilot projects in the United States have demonstrated success in increasing capacity and reducing costs, the report identifies significant barriers to scaling these solutions, including risk aversion, financial disincentives, and a failure to integrate ATTs into long-term grid planning. RMI suggests that large corporate energy users can accelerate adoption through policy advocacy and by facilitating coordination between utilities across different service territories.

• Advanced transmission technologies (ATTs), which include grid-enhancing technologies (GETs) and advanced conductors, provide a cost-effective way to increase grid capacity and reliability compared to other options. Pilot projects in the United States have shown tangible results: dynamic line rating (DLR) projects in the Midwest increased capacity on existing lines by 40% during winter, and an advanced power flow control (APFC) project in upstate New York freed up 185 MW of capacity, enabling lower-cost resources to serve an additional 130,000 homes.
• Advanced conductors have been used in the U.S. for over two decades, with a significant 2015 project by AEP that used ACCC conductors to double the capacity of 240 miles of transmission lines. This specific deployment was estimated to reduce line losses by 30% without causing service disruptions.
• Despite successful pilots, ATTs face scaling barriers beyond risk aversion and financial disincentives. Two primary obstacles are the tendency of utilities to use ATTs for operational risk reduction rather than for capacity planning, and a lack of coordination between utilities that share transmission corridors. Because the grid has 'patchwork ownership,' the benefits of a technology like DLR can be limited if a neighboring utility on the same line maintains a static rating.
• Large corporate energy users can drive the scaling of ATTs through policy advocacy and by acting as catalysts for cross-utility collaboration. Policy efforts can include urging states to require ATT evaluation in transmission and integrated resource planning (IRP). Recent examples include legislation in California and Minnesota, as well as corporate interventions in North Carolina and a settlement with Indiana Michigan Power requiring GETs studies for its next IRP.

APA

RMI (2025). Getting Alternative Transmission Technologies to Scale. https://rmi.org/resources/getting-advanced-transmission-technologies-to-scale/

Chicago

RMI. Getting Alternative Transmission Technologies to Scale. 2025. https://rmi.org/resources/getting-advanced-transmission-technologies-to-scale/.

Wikipedia

{{cite report |author=RMI |title=Getting Alternative Transmission Technologies to Scale |date=18 March 2025 |url=https://rmi.org/resources/getting-advanced-transmission-technologies-to-scale/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2025getting, author = {{RMI}}, title = {{Getting Alternative Transmission Technologies to Scale}}, institution = {RMI}, year = {2025}, month = mar, url = {https://rmi.org/resources/getting-advanced-transmission-technologies-to-scale/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }