The US power system could accommodate as much as 100 GW of additional load without major capacity or transmission expansion through "load flexibility," or short-duration load curtailment by large customers, according to a new study by Duke University.
As US load growth projections continue to mount — driven by increasing demand from datacenters, industrial manufacturing and electrification — power providers and utilities are making plans to add capacity, in some cases with increasing urgency.
Aggregate US winter peak load is expected to grow nearly 22% over the next decade, rising from 694 GW to 843 GW by 2034, according to the 2024 long-term reliability assessment from the North American Electric Reliability Corp., representing a 10-year compound annual growth rate (CAGR) of 2%, higher than any period since the 1980s. The Federal Energy Regulatory Commission's latest five-year outlook forecasts 128 GW in peak load growth as early as 2029, a 3% CAGR.
"Protracted interconnection queues, supply chain constraints and extended permitting processes, among other obstacles, are limiting the development of new power generation and transmission infrastructure," the study authors wrote.
The Duke study, released Feb. 11 by the university's Nicholas Institute for Energy, Environment and Sustainability, found that load flexibility could be key to meeting that demand at considerably lower risk.
The study analyzed 95% of the nation's power system and found potential for accelerating the addition of large-load customers such as datacenters and major manufacturing while mitigating the need for expensive new capacity additions, providing those loads can occasionally shift their power use for short periods when the grid sees highest demand.
Datacenters and other large-load customers could temporarily reduce their energy consumption by using on-site generators, shift workload to other facilities or reduce operations, according to the study.
The five balancing authorities with the largest potential load integration at a 0.5% annual curtailment were the PJM Interconnection LLC at 18 GW, Midcontinent ISO at 15 GW, Electric Reliability Council of Texas Inc. at 10 GW, Southwest Power Pool at 10 GW and Southern Co. at 8 GW, according to the study, "Rethinking Load Growth: Assessing the Potential for Integration of Large Flexible Loads in US Power Systems."
The study demonstrates that existing US power system capacity, "intentionally designed to handle extreme peak demand swings — could accommodate significant load additions with modest flexibility measures," the report authors wrote.
The Duke study analyzed the volume of new load that could be added in each of the 22 largest balancing authorities in the US before total load exceeds what system planners are already prepared to serve, provided the new load can be temporarily curtailed when needed.
The study suggested that load flexibility may offer a near-term strategy for regulators and market participants to more quickly integrate new loads and reduce costs from potential capacity expansion.
The study found that 76 GW of new load, about 10% of US peak demand, could be integrated with an average load curtailment rate of about 0.25%. About 98 GW could be integrated into the system with a curtailment rate of 0.5%, and 126 GW at 1%.
The average curtailment event suggested in the study would last about two hours, consistent with existing short-duration battery technology.
The total number of hours per year that curtailment may be necessary is comparable to existing US demand response times, the study found.
