The hidden transmission capacity of the American West

The western U.S. and Canada electricity grid is significantly underutilized in many areas, and the fastest way to bring new data centers online is to unlock capacity on the existing grid, a new Stanford University study finds.

Across the United States, an aging grid in some places is struggling to keep up with greater electricity demand, and more soon will, due to new data centers and ongoing electrification of industry, buildings, and transportation. In addition, huge amounts of new generation are kept from connecting to the grid due to transmission limitations and a slow-moving approval process in many parts of the country. New, high-voltage transmission lines typically take eight to 12 years to build, primarily due to painful permitting procedures. Large power transformers and substation equipment are in critically short supply, with lead times now stretching to several years.  This bottleneck threatens to slow the clean energy transition and undermine U.S. economic growth.

However, analysis of the western grid may point to some near-term solutions. With transmission lines throughout the West operating well below capacity, the region’s grid has substantial room to serve new load and integrate new generation more quickly and affordably, the study’s researchers say.  In highly stressed corridors, the priority investments should be in large transformers, which ramp up voltage for long distance transmission and downshift it for eventual use in large loads. Targeted replacement, refurbishment, and added flexibility of transmission assets, like transformers and short-distance transmission lines, could increase total grid utilization where it’s needed most for much less cost than building new long-distance transmission lines, the study finds.

“By better using the transmission system already in place, we can increase overall capacity to serve large loads in the near term and spread grid costs across more customers,” said Liang Min, the study’s senior author and managing director of the Bits & Watts Initiative, a grid modernization research and education program in Stanford’s Precourt Institute for Energy. The Precourt Institute is part of the Stanford Doerr School of Sustainability.

“This could go a long way in limiting electricity rate increases for existing customers and in keeping the grid reliable until the new transmission lines can be built,” Min added.

To be sure, new transmission lines will be badly needed soon and, in some cases, are needed now.

The study, “U.S. Transmission System Utilization Study Phase 1: WECC,” is part of a series of flash research projects catalyzed by a meeting of electricity sector leaders on challenges to the U.S. grid in February this year at Stanford. Four other flash studies are wrapping up. Min and co-author Rajanie Prabha, a PhD candidate in civil and environmental engineering,  expect a more detailed, technical study from their work to be published early in 2026 in a peer-reviewed scientific journal.

Western grid

The new study examined North America’s western grid, which runs from New Mexico to Alberta, Canada and everything west of those states. By a wide margin, this is the largest of the six U.S.-Canada regional electricity grids. Within these regional grids, electric utilities transfer power among each other via transmission lines to, in theory at least, meet demand most economically for utilities in their region. Regional utilities maintain system reliability and plan for the future through regional associations, like the Western Electricity Coordinating Council.

Min analyzed utilization of WECC’s transmission network for peak demand, mostly on hot summer weekdays. They looked for stress points, bottlenecks, and underutilization during peak demand. High demand peaks cover about 90 hours a year. Given access to WECC data, they found that even with power use at its peak, utilities in the region used only 18% to 52% of the capacity of their transmission lines, with most utilities clustered around 30% of capacity.

However, now and in the medium term transformers face more stress than transmission lines do during peak demand days and normal operations, according to the study. Under peak conditions each utilities’ transformer assets operated at between 28% and 68% of total capacity with most utilities clustered around 45% of capacity.

“We’re also studying the Eastern Interconnection. Although our current results are from the Western grid, early patterns look similar, suggesting a larger opportunity to better use existing infrastructure for load growth and generation integration,” said Prabha, whose PhD advisory is associate professor Ram Rajagopal.

Policy implications

The study reveals several opportunities to guide how and where to optimize and expand U.S. electricity infrastructure to handle rapid demand growth:

• Studies like this one, resulting in a “utilization map,” can help steer new data centers, industrial plants, and major generating projects toward corridors and regions with available headroom, avoiding long waits for new transmission lines and interconnection approvals.
• By adding new, steady load growth in the right locations, the United States can increase use of existing grid infrastructure, spread costs among more customers, and modernize its infrastructure more affordably.
• Targeted investments in transformer capacity in highly stressed corridors can unlock additional transfer capability, increase overall system utilization, and do so more cost-effectively than building new long-distance lines.

In the long term, much of the U.S. electricity infrastructure is old and needs to be replaced. This, combined with new demand, will require tremendous investments. Designing and renovating the system at an appropriate scale ahead of forecasted growth would be economically prudent, the study advises.

“The quick funding and dissemination of insights from research like this can help us manage immediate and important challenges, like serving new electricity demand for the AI boom,” said William Chueh, faculty director of the Precourt Institute and Kimmelman professor of materials science and engineering in the School of Engineering, of energy science and engineering in the Doerr School of Sustainability, and of photon science at SLAC National Accelerator Laboratory.