Large Loads and System-Wide Transmission

The policy brief advocates for system-wide transmission planning over the customer-by-customer load interconnection process to manage rapid electric load growth. It highlights that system-wide planning, which evaluates needs over 5 to 20 years, leads to more efficient grid design and higher benefit-to-cost ratios. To manage the risk of anticipated load not materializing, the document recommends scenario planning to identify "least-regrets" projects and phased, modular investment strategies with built-in triggers, illustrated through case studies from the Southwest Power Pool, ERCOT in Texas, and NV Energy in Nevada.

• System-wide transmission planning is more efficient and provides greater value than the load interconnection process. Analysis of seven system-wide projects in the United States showed benefit-to-cost ratios between 1.1 and 3.9, with the Valley–Colorado River project near Los Angeles delivering annual benefits approximately 3.3 times its cost since 2013.
• While system-wide planning cycles take longer (one to three years) than interconnection studies, the overall timeline for transmission development is dominated by approval, permitting, and construction. In PJM, interconnection-driven upgrades have taken an average of 2.3 to 4.8 additional years to reach in-service after approval, meaning system-wide planning only adds 6 months to 1.5 years to the total front-end timeline.
• Scenario planning can mitigate the financial risk of load growth uncertainty. The Southwest Power Pool’s 2025 Integrated Transmission Plan (ITP), which includes $19 billion in projects and over 2,000 miles of 765 kV backbone transmission, demonstrated a benefit-to-cost ratio of 9.4 in a high-growth future (3.9% annual growth) and 5.7 in a lower-growth future (1.7% annual growth).
• Phased or modular planning allows utilities to scale investments based on actual demand triggers. ERCOT's Delaware Basin Load Integration study used five trigger stages based on peak demands (from 3.1 to 5.4 GW) to activate upgrades. Similarly, NV Energy's plans for Reno (7.5 GW anticipated growth) and Las Vegas (1.7 GW anticipated growth) align investments with specific percentages of projected load.

APA

RMI (2026). Large Loads and System-Wide Transmission. https://rmi.org/resources/large-loads-and-system-wide-transmission/

Chicago

RMI. Large Loads and System-Wide Transmission. 2026. https://rmi.org/resources/large-loads-and-system-wide-transmission/.

Wikipedia

{{cite report |author=RMI |title=Large Loads and System-Wide Transmission |date=14 April 2026 |url=https://rmi.org/resources/large-loads-and-system-wide-transmission/ |access-date=17 August 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmi2026large, author = {{RMI}}, title = {{Large Loads and System-Wide Transmission}}, institution = {RMI}, year = {2026}, month = apr, url = {https://rmi.org/resources/large-loads-and-system-wide-transmission/}, urldate = {2026-08-17}, note = {Indexed by Climate Insights Directory} }