Oncor, the transmission and distribution operator behind 4 million Texan meters
Oncor Electric Delivery operates the largest transmission and distribution system in Texas, delivering electricity to more than 4 million homes and businesses across 143,000 circuit miles of T&D lines. The company is a regulated wires-only utility (it does not sell electricity), and its grid covers about a third of the state, including the Dallas-Fort Worth metroplex.
- The size of the Oncor network and the regions it covers
- Why power outages happen on the Oncor grid
- The PUCT-approved $3 billion System Resiliency Plan and the $36 billion 2025-2029 capital plan
- How Oncor uses smart-grid technology, automation and vegetation management to reduce outages
A pure-play T&D utility inside the ERCOT grid
Oncor's footprint stretches from the West Texas plains to the East Texas piney woods, and from the Red River to the Central Texas hills. The grid serves a mix of dense urban areas (Dallas-Fort Worth metroplex), suburbs, oil and gas country, and rural farmland.
- More than 4 million electric customers in Texas.
- About 143,000 circuit miles of transmission and distribution lines, the largest T&D network in Texas.
- Service area covers around one third of Texas, including the Dallas-Fort Worth metroplex.
- About 40% of new ERCOT load growth through 2030 is expected to land on the Oncor grid, driven by data centers, manufacturing and industrial electrification.
Oncor is regulated by the Public Utility Commission of Texas (PUCT) and is majority-owned by Sempra (NYSE: SRE), with Texas Transmission Investment LLC as minority owner. The company is headquartered in Dallas.
Why Texas heat, ice storms and tornadoes hit Oncor's lines
With a footprint that crosses several climate zones, Oncor's grid is exposed to a wide range of outage drivers. Severe weather is the dominant cause, but vegetation, equipment age and wildfire risk all contribute.
Severe weather
Thunderstorms, tornadoes, ice storms, hail, extreme heat and extreme cold all hit the Oncor territory. The May 2024 storm sequence across North Texas was severe enough that Oncor received the EEI Emergency Response Award in January 2025 for its restoration work.
Wildfire risk
Texas has experienced major wildfire events in recent years, particularly in dry and windy parts of the territory. Oncor has dedicated wildfire mitigation zones with fire-safe device deployment and hardening of assets in high-risk areas.
Trees and vegetation
Tree contact remains a recurring cause of unplanned power outages. Oncor is more than doubling vegetation maintenance under its current resiliency plan and using satellite, lidar and drone imaging to spot risks earlier.
Aging poles and equipment
Older poles, crossarms, transformers and underground cables fail more often. Hardening overhead and underground systems is the largest single line item in the System Resiliency Plan.
A $36 billion capital plan from 2025 to 2029
In November 2024, the PUCT approved Oncor's first System Resiliency Plan (SRP), unlocking around $3 billion of additional grid investment over four years. The SRP sits inside a much larger five-year, $36.1 billion capital plan for 2025 to 2029, with $7.1 billion of that scheduled for 2025 alone.
Oncor System Resiliency Plan in numbers
About $2.9 billion in capital expenditures plus $520 million in O&M for 2025 to 2027.
$1.83 billion to modernize and harden overhead and underground systems.
$510 million to expand distribution automation.
$285 million to more than double vegetation management activity.
$900 million for wildfire mitigation.
$525 million for cybersecurity and $80 million for physical security.
Total 5-year capital plan: $36.1 billion for 2025 to 2029.
Oncor was awarded the EEI Emergency Response Award in January 2025 for its work on the May 2024 North Texas storms, which is the type of recognition utilities cite when filing rate cases to recover the cost of resiliency work.
Distribution automation and storm response across 13 service areas
Distribution automation and self-healing grid
Oncor is expanding its distribution automation footprint with intelligent switches, new ties and additional capacity. These devices sense power flow, redistribute load, identify faults and in many cases restore service automatically without crew dispatch.
Overhead and underground hardening
Hardening covers stronger poles, upgraded crossarms, lightning protection, increased capacity and modernization of underground systems through cable injection, replacement and switchgear automation.
VM+ vegetation program
The expanded VM+ program more than doubles vegetation maintenance and combines it with remote-sensing tools, including satellite imaging and lidar, to identify risk earlier and prioritize problem segments.
Wildfire risk modeling and fire-safe devices
Wildfire mitigation zones receive fire-safe device deployment, advanced wildfire risk modeling and asset hardening. The combined approach is similar in spirit to PG&E's California program but adapted to Texas conditions and wind patterns.
The Oncor StormCenter and outage tools
Oncor outage map
Oncor publishes a public outage map updated in near real-time. Customers can search by address or zip code to see the size of an outage, estimated restoration time and crew status.
Retail provider model
Texas operates a deregulated retail electricity market for most of the state. Oncor delivers electricity over its wires, but customers buy their actual power from a Retail Electric Provider (REP) of their choice. During an outage, customers report and check status with Oncor, while billing and rate questions go to their REP.
Mobile app and alerts
The MyOncor mobile app gives access to the outage map, lets customers report a power outage and pushes proactive SMS, email and app notifications when service is interrupted.
CenterPoint and the main Texas ISPs
For a wider view of how the U.S. electric grid works and why outages happen, see the U.S. power outage page. The other major Texas utility is CenterPoint Energy in the Greater Houston area. For internet outages across the same Texas footprint, the most common providers are AT&T, Spectrum and Xfinity.