Transmission and distribution utilities and system operators

Why the concentration exists

The US electricity grid consists of three main interconnections: the Eastern Interconnection, the Western Interconnection, and the Electric Reliability Council of Texas. These interconnections link over 7,300 power plants to 145 million customers through nearly 160,000 miles of high-voltage power lines. Millions of miles of low-voltage distribution lines and distribution transformers complete the network. More than 3,000 utilities generate, transmit, and distribute electricity across the country.[7][8][14]

Regional Transmission Organizations and Independent System Operators coordinate power flow in restructured markets. These entities replaced utilities as grid operators following deregulation and now operate wholesale electricity markets. There are seven ISOs and four RTOs operating in North America. In most restructured states, distribution utilities own and operate the distribution system and some portion of the transmission system.[4][5][14][2]

What the evidence shows

Who supplies it

More than 3,000 utilities operate across the United States, encompassing investor-owned companies, municipally owned utilities, and electric cooperatives. In North America specifically, seven Independent System Operators and four Regional Transmission Organizations manage wholesale electricity markets and grid operations. Each entity operating as a Transmission Service Provider or Distribution Service Provider within regions like ERCOT must register accordingly. This includes municipally owned utilities and electric cooperatives.[14][1]

Investor-owned electric companies represent the largest source of capital investment in grid infrastructure. These companies spent $32.6 billion on transmission investment in 2024, up from $30.0 billion in 2023. They spent $60.2 billion on distribution investment in 2024, up from $56.7 billion in 2023. They are planning to invest approximately $178 billion on transmission construction between 2025 and 2028.[16]

Globally, distribution system operators vary significantly in scale. MRSK Yug PAO was the leading distribution system operator in the world in 2021 by total length, with 2,400,000 circuit kilometers. Enel SpA ranked among the leading operators with more than 2.23 million kilometers. The top 10 distribution system operators globally had a cumulative total length of 13,270,285 circuit kilometers in 2021.[15]

What it depends on, and what depends on it

Meeting growing electricity demands requires substantial expansion of transmission infrastructure. Independent estimates indicate transmission systems need to expand by 60 percent by 2030. They may need to triple by 2050 to meet clean electricity demands. Transmission, distribution, and storage already employ over one million people in the United States.[6]

Where it sits in the stack

What would break it

Equipment supply constraints have created structural imbalances in the US transformer market. Wood Mackenzie's August 2025 analysis found power transformer demand up 119 percent since 2019. Distribution transformer demand was up 34 percent over the same period. The 2025 supply deficit was roughly 30 percent for power transformers and 10 percent for distribution units.[11]

Large power transformers are averaging 128 weeks of lead time, while generator step-up units require 144 weeks. The National Laboratory of the Rockies reported that 55 percent of in-service US distribution transformers are already more than 33 years old. The average lifespan is roughly 30 to 40 years. More than 40 million US distribution transformers are already beyond their expected service life.[10]

Regulatory reforms have attempted to address interconnection bottlenecks. In July 2023, FERC issued Order No. 2023, replacing the 'first come, first served' approach with a 'first ready, first served' approach for generator interconnection. In May 2024, FERC issued Order No. 1920 on long-term regional transmission planning. An earlier order eliminated the right of first refusal for incumbent utilities in regional infrastructure construction.[13][3]

What to watch

Chubu Electric in Japan will increase the interconnection capacity of the Higashi Shimizu Substation from 300 MW to 900 MW. Operations are expected to begin by 2027. The Organization for Cross-regional Coordination of Transmission Operators supervises power interchange among electric power companies in Japan.[12]

Investor-owned electric companies are planning to invest approximately $178 billion on transmission construction between 2025 and 2028. CAISO's 2024-2025 transmission plan recommended 28 reliability-driven transmission projects, compared to 19 in the 2023-2024 plan. Associated spending fell from $6.1 billion to $4.8 billion year over year. The plan reflects an increase in peak demand growth from 0.99 percent to 1.53 percent year over year.[16][9]

Related nodes

Sources

1. ercot.com
2. nga.org · 2021-10-26T18:23:56
3. law.lclark.edu
4. rff.org
5. epsa.org · 2025-10-28T19:38:28
6. energy.gov
7. eia.gov
8. epa.gov · 2016
9. utilitydive.com · Feb. 10, 2026
10. powermag.com · Q2 2025
11. powermag.com · August 2025
12. en.wikipedia.org · 2027
13. publicpower.org · 2023-07
14. ptr.inc
15. globaldata.com · 2021
16. eei.org · 2024