Why does Texas have its own power grid?

A brief history on ERCOT and Texas’ unique interconnection island

Oct 19, 2021

US Electric Grids — Image: US Department of Energy Public Domain

You may have heard at one time or another that Texas has its own power grid. While this is generally true, it is not technically the case. In reality, Texas is the only state in the Union that sits on all three interconnections in the Lower 48.

There are three general “power grids,” or interconnections, in the continental United States. The largest of the three is the Eastern Interconnection, followed by the Western Interconnection, and then ERCOT, commonly known as Texas’ independent power grid. According to ERCOT, about 90% of Texas’ electrical load (demand) resides within their interconnection covering 75% of the state’s land area.1

ERCOT is often referred to as an island. A self-sustaining electrical paradise with minimal routes in or out for power to flow. The primary driver for Texas to have its own grid was to be removed from the federal government’s purview. In 1935, President Franklin Delano Roosevelt signed into law the Federal Power Act granting the federal government regulatory authority over interstate utility transactions.2 The justification fell under the Interstate Commerce Clause of the US Constitution. To avoid scrutiny under the FPA, Texas utilities kept their grid interconnected intrastate creating the Texas Interconnected System. There are unique quirks regarding power flow to other states in and out of Texas that I will cover in follow up articles, so stay tuned if this interests you.

The Texas grid by the early 1940s was centered around major cities with power plants built near industrial centers to support the World War II war effort. The more rural areas of Texas were isolated in these early days. Given the grand expanse of the state of Texas, these regions never were brought into the Texas Interconnected System. Cities such as Amarillo in the Panhandle and El Paso on the far western edge are in the Eastern and Western Interconnections, respectively. These areas of Texas tied into the other power grids given physical proximities to other states. Rural and remote areas of the country were still undergoing the dawn of electrification.

ERCOT Grid — Image: State of Texas Comptroller Public Domain

Decades later the Texas Interconnected System gave way to the Electric Reliability Council of Texas, or ERCOT, in 1970.3 Today, ERCOT still operates the Texas grid independently with no intentions of joining the larger interconnections. The system itself is larger than many countries and has proven to be self-sufficient for over 80 years.

Operating as a separate grid, ERCOT is physically asynchronous from the Eastern or Western Interconnections. Problems that arise in Oklahoma, for instance, do not directly impact ERCOT and vice versa. However, Oklahoma shares the same balancing authority as parts of Montana and North Dakota, so some issues in either of these states will impact one another.

The benefits of being on your own electrical island is independence and self-reliance. That also ushers in limitations for outside help. During the February 2021 cold weather blackouts, the ERCOT grid was by far the most negatively impacted. Texans in El Paso or the Panhandle were insulated from the worst of the energy crisis as they operate on separate interconnections entirely. When a crisis affects ERCOT, unfortunately there are not many tools available for assistance given they are physically separated.

The situation across the Red River in Oklahoma was starkly different. Although Oklahomans experienced controlled blackouts, the interdependence with other utilities mitigated the crisis. Generators in other portions of the Eastern Interconnection helped the power shortages in this area of the country. The Western Interconnection was spared controlled blackouts entirely. So residents in El Paso, Texas fared better than Amarillo in the Eastern Interconnection or Houston in ERCOT.

Although uncommon and very expensive, utilities can choose to join or leave an interconnection entirely. The most recent instance is Lubbock Power & Light. On June 1, 2021, 70% of LP&L’s load left SPP and the Eastern Interconnect to join ERCOT.4 This required hundreds of millions of dollars of transmission upgrades to connect Lubbock’s assets to the ERCOT grid.

Texans are proud of their independent culture and rightfully so. Nothing cries autonomy more than having self-sustaining power grid for 26 million residents. The model is criticized from time to time, but they have accomplished and maintained a unique system serving them well for decades. Ultimately, they are accountable to themselves and seem content to keep it that way. Just ask Lubbock!

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