The Electric Reliability Council of Texas, known as ERCOT, operates the power grid that serves about 90 percent of the state and delivers electricity to more than 27 million people. If you’ve ever wondered what ERCOT does, the short answer is that it keeps the lights on: it balances electricity supply and demand every second, runs the wholesale market where generators sell power, coordinates the retail market that lets Texans pick an electricity provider, and takes emergency action when the grid is stressed. ERCOT connects more than 54,000 miles of high-voltage transmission lines and over 1,460 generation units into a single system that operates largely independent of the rest of the country.1Electric Reliability Council of Texas. About ERCOT
ERCOT is a membership-based 501(c)(4) nonprofit. It does not generate electricity, own power lines, or sell power to consumers. It functions as a neutral operator coordinating generators, transmission companies, and retail providers, and it answers to the Public Utility Commission of Texas (PUCT) and the Texas Legislature rather than to federal energy regulators.1Electric Reliability Council of Texas. About ERCOT
Balancing Supply and Demand on the Grid
The core technical job is keeping electricity production and consumption in constant balance. Operators monitor the entire system around the clock from a central control facility, directing power plants to ramp output up or down to hold the grid’s frequency at a steady 60 hertz. Frequency matters because generators, transformers, and motors across the grid are synchronized to it. If the frequency drifts too far in either direction, equipment can be damaged and large portions of the grid can trip offline in a cascading failure.2Houston Chronicle. What Are the Different ERCOT Warnings? Heres a Guide to Power Grid Notices
Behind the scenes, forecasting software predicts future demand using weather patterns, historical consumption, and real-time conditions. Operators continuously evaluate power flows across the transmission network to prevent thermal overloads on individual lines, the kind of problem where one overloaded line trips and pushes its load onto neighboring lines until they trip too.
The Public Utility Regulatory Act gives ERCOT legal authority to direct the actions of power generators, transmission providers, and other market participants. Every entity operating in the Texas Interconnection must follow ERCOT’s scheduling, operating, planning, reliability, and settlement procedures, and the PUCT can impose administrative penalties for noncompliance.3State of Texas. Texas Utilities Code Chapter 39 – Restructuring of Electric Utility Industry
Running the Wholesale Electricity Market
ERCOT runs the financial marketplace where generators sell electricity and load-serving entities buy it. Market participants submit bids and offers through a centralized platform, and ERCOT clears transactions in two main timeframes: a day-ahead market that sets prices for the following day, and a real-time market that adjusts prices based on actual conditions. Wholesale energy prices are capped at $5,000 per megawatt-hour, a ceiling designed to let prices spike high enough during scarcity to encourage new generation investment without allowing unlimited exposure.
After the trading day ends, ERCOT calculates the exact energy each generator produced and each entity consumed, then determines the payments required to settle up. Market participants must post collateral or letters of credit to cover potential obligations. If a company defaults, ERCOT manages the shortfall process to limit damage to other participants.
Ancillary Services
Beyond raw energy, ERCOT procures several categories of ancillary services. These are reserves that generators and certain large consumers hold ready to deploy on short notice:
- Regulation Up and Down adjusts generation output every few seconds to keep frequency stable during normal operations.
- Responsive Reserve can respond almost immediately if a large generator unexpectedly trips offline.
- ERCOT Contingency Reserve is available within 10 minutes to cover forecasting errors or replace reserves that have already been deployed.
- Non-Spinning Reserve can come online within 30 minutes as a deeper backstop.4ERCOT. Ancillary Services Handout
Without these reserves, the grid would have no buffer between normal operations and emergency load shedding every time a power plant tripped or a weather forecast missed by a few degrees.
Making Retail Choice Work in Texas
In the deregulated parts of Texas, residents and businesses can choose their retail electricity provider. ERCOT doesn’t sell power to consumers, but it manages the infrastructure that makes retail competition work. The backbone of that system is the Electronic Service Identifier, or ESI ID, a unique number assigned to every electric meter in competitive regions. The ESI ID links each meter to the correct retail provider and ensures usage data flows accurately from the utilities that own the wires to the retail companies that send bills.5Electric Reliability Council of Texas. Retail Market Information
When you switch electricity providers, ERCOT processes the request and updates the ESI ID records so the new provider gets credited for your usage and the old provider stops billing. The handoff has to be precise. Errors mean a customer gets billed by two providers at once, or a provider doesn’t get paid for power its customer consumed.6Electric Reliability Council of Texas (ERCOT). The Value of Mapping Electric Service Identifier to Common Information Model Network Model Load
Consumer protections in the retail market, including rules on billing, disconnection, deposits, privacy, and unauthorized provider switches, are set by the PUCT and apply to the retail providers themselves rather than to ERCOT. ERCOT’s transaction processing is what makes enforcement of switching and billing rules operationally possible.
Emergency Alerts and Rotating Outages
When available power reserves drop dangerously low, ERCOT escalates through a series of Energy Emergency Alert (EEA) levels, each triggering a more aggressive response:
- EEA Level 1 is declared when operating reserves fall below 2,500 MW and aren’t expected to recover within 30 minutes. ERCOT issues public conservation appeals and calls on all available generation.
- EEA Level 2 is declared when reserves drop below 2,000 MW, or when grid frequency falls below 59.91 hertz for 15 minutes. ERCOT may begin reducing industrial loads that have agreed to curtailment contracts.
- EEA Level 3 is declared when reserves fall below 1,500 MW, or when frequency drops below 59.8 hertz at any point. This is the threshold for ordering rotating outages across the grid.7ERCOT.com. 2024 Energy Emergency Alert Overview
Rotating outages work exactly the way they sound. ERCOT tells transmission operators how much total load needs to come offline, and each operator shuts down portions of its service area in rotation so no single neighborhood stays dark the entire event. Each operator’s share is based on its percentage of the previous year’s system-wide peak demand. Target durations vary, but smaller operators typically aim for 10 to 30 minutes per rotation while larger operators may go 60 minutes or longer.8ERCOT.com. ERCOT Trending Topics – Using Load Shed to Address Shortages in the Generation Supply
Hospitals, police stations, water treatment plants, and nursing homes are generally prioritized during rotating outages, but even they can lose power during a deep or prolonged event. The critical-load designation is managed by local distribution providers, not ERCOT, and it doesn’t guarantee uninterrupted service. Customers who qualify must register with their local provider and renew that registration periodically.8ERCOT.com. ERCOT Trending Topics – Using Load Shed to Address Shortages in the Generation Supply
Weatherization and Fuel Reliability After 2021
The February 2021 winter storm was a turning point for ERCOT. Millions of Texans lost electricity for days during subfreezing temperatures when roughly a third of the state’s generation capacity went offline, largely because power plants and natural gas infrastructure froze. The Legislature responded with reforms that changed how generators and transmission providers prepare for extreme weather, and enforcing those rules is now a significant part of what ERCOT does.
Under PUCT rules at 16 TAC ยง 25.55, every generation facility and transmission service provider in the ERCOT system must complete detailed winter weatherization measures by December 1 each year. Generators must install and maintain wind breaks, insulation, freeze protection equipment, and instrument air moisture prevention for all cold-weather critical components. They must arrange sufficient backup fuels and chemicals for sustained operations during a winter emergency. Transmission providers must confirm the operability of all systems containing cold-weather critical components. Both must train operational personnel on winter weather procedures and review staffing plans for emergency conditions.9ERCOT.com. Generation Entity and Transmission Service Provider Winter Inspection Checklists
ERCOT inspects facilities from December through late February to verify compliance. The standard is specific: facilities must be able to sustain operations at the 95th percentile minimum average 72-hour wind chill temperature for their weather zone, a statistical benchmark designed to ensure equipment survives all but the most historically extreme cold snaps.
Fuel supply was another lesson from 2021. Even properly weatherized generators can’t run without fuel, and natural gas disruptions caused many plant failures during the storm. The Legislature directed ERCOT to create a Firm Fuel Supply Service that pays generators meeting a higher resiliency standard to maintain guaranteed fuel availability during extreme cold. ERCOT procures these resources through a competitive request-for-proposal process, with the obligation period running from November 15 through March 15 each winter.10Electric Reliability Council of Texas. Firm Fuel Supply Service
Planning the Transmission Network
ERCOT is responsible for planning and overseeing the physical transmission network that carries electricity from generators to the local distribution systems serving homes and businesses. That includes reliability studies to identify parts of the grid that need reinforcement as demand grows or new generation comes online in different locations. State rules require ERCOT to facilitate open, nondiscriminatory access to the transmission system for all buyers and sellers of electricity.11Cornell Law School. 16 Texas Admin Code 25-361 – Electric Reliability Council of Texas (ERCOT)
New generation resources must go through a formal interconnection process before they can begin delivering power. ERCOT’s Resource Integration team guides developers through technical studies that verify a new facility won’t create reliability problems on the existing network. Engineers review everything from protective relay settings to thermal limits on nearby transmission lines. The process can take years for large projects, and the queue has grown substantially as Texas has attracted new investment in solar, wind, natural gas, and battery storage.12ERCOT. Resource Integration
This planning function has become more complex over time. Texas has one of the fastest-growing electricity demands in the country, driven by population growth, industrial expansion, and large data center developments. ERCOT’s long-range transmission planning has to anticipate where that demand will materialize and ensure the wires connecting generation to load can handle it, a job that shapes billions of dollars in infrastructure investment across the state.