New report from the ESIG Large Loads Task Force identifies critical gaps in U.S. large load interconnection processes and provides recommendations to address them

The Energy Systems Integration Group (ESIG) today released the report Interconnection Processes for Large Loads: Current Practices and Recommendations, a comprehensive technical assessment of how the U.S. electric power system handles—and often struggles to handle—the surging volume of large load interconnection requests from data centers, advanced manufacturing, and other facilities.

The report, produced by ESIG’s Large Loads Task Force, examines current interconnection practices across utilities and ISO/RTOs, maps the gaps and bottlenecks driving delays and reliability risk, identifies emerging best practices, and distills a set of recommendations for creating a more comprehensive, transparent, harmonized, and efficient interconnection process. It arrives at a pivotal moment. On June 18, FERC issued show cause orders directing all six RTOs/ISOs to justify or reform how they interconnect large loads, on timelines as short as 30 to 60 days. ESIG’s report offers a technically grounded benchmark of current practice—a way to measure those forthcoming responses against how interconnection actually works today—informed by lessons learned from integrating large amounts of solar, wind, and battery storage in recent years, which posed some of the same challenges we’re seeing now with large loads.

“The interconnection process is the starting point for every large load project, and right now it is under enormous pressure,” said Kyle Thomas of Elevate Energy Consulting, a lead author of the report. “Interconnection requests have grown exponentially in number and magnitude, and the processes meant to manage them—the studies, the legal agreements, the procedural requirements—are fragmented across regions and largely ungoverned at the national level. This report aims to give the industry a clear, objective picture of what’s happening and a practical path toward reform.”

Among the report’s core findings:

• Interconnection processes vary significantly across utilities and regions, with many jurisdictions relying on procedures that were not designed for large load facilities of today’s scale.
• Coordination between utilities and ISOs/RTOs, where necessary, is inadequate, creating duplicated effort and inconsistent visibility into cumulative system impacts.
• The question remains unresolved as to which regulatory authorities—FERC, NERC, states, ISOs/RTOs, or utilities—hold jurisdiction over large load interconnection standards and procedures.

“We saw a version of this problem before with generator interconnection of large amounts of solar and wind, and this was also fragmented and inconsistent before FERC standardized it through rulemaking,” said Julia Matevosyan, Associate Director and Chief Engineer at ESIG and co-author of the report. “That process took time, and the industry learned from it. Those lessons inform the recommendations in this report, which are relevant to what comes next as the regulatory landscape on large loads continues to move.”

The report’s recommendations include:

• The development of a potential FERC Large Load Interconnection Procedure modeled on existing interconnection processes for generation
• Enhanced coordination between utilities and ISOs/RTOs through formal information-sharing protocols and joint study procedures
• Transition to cluster study approaches as the volume of large load interconnection requests grow; inclusion of generation interconnection projects and planned transmission system upgrade/new build projects into one integrated transmission planning study is also recommended
• Clear performance and capability requirements tied to NERC reliability standards
• Expanded availability of flexible interconnection options—including non-firm, surplus, and provisional service—to accelerate large load interconnection where firm service is not immediately available

The report is part of ESIG’s 11-report Large Loads Task Force series, which was established to assist the power industry in addressing new challenges introduced by the rapid proliferation of large electronic loads. It was prepared by Kyle Thomas of Elevate Energy Consulting and Julia Matevosyan of ESIG, with Alex Shattuck of ESIG and Lisa Schwartz of Lawrence Berkeley National Laboratory serving as project managers. The work was supported by the U.S. Department of Energy under Lawrence Berkeley National Laboratory Contract No. DE-AC02-05CH11231.

Interconnection Processes for Large Loads: Current Practices and Recommendations is available at esig.energy/reports-briefs/large-load-interconnection-process.