The Summer Grid Stress Map: Which Texas Cities Push the Grid the Hardest?

Every summer, Texas headlines fill up with stories about the grid buckling under heat and demand. But the pressure isn’t spread evenly across the state. Some metros have the kind of housing, growth patterns, and cooling habits that make their share of peak demand far heavier per household than others. To find out which Texas cities push the grid the hardest, Payless Power built a Summer Power Index that ranks 26 metros on three per-household factors tied to peak summer load.

Key Takeaways

• Sherman-Denison, Lubbock, and Wichita Falls top the list of Texas cities most exposed to summer grid stress in 2026.
• Austin leads Texas in population growth since 2020 (12%), yet ranks 17th of 26 for summer grid exposure on the 2026 Summer Power Index.
• Three of Texas’s most grid-stressed cities (Lubbock, Wichita Falls, and Amarillo) share a weather zone with one-twelfth the capacity of Dallas-Fort Worth’s.
• Nearly half of Brownsville-Harlingen homes have no central AC, more than triple the Texas median.
• El Paso has the highest rate of homes relying on evaporative cooling instead of central AC in Texas at 98%.

The 2026 Texas Summer Power Index

When most people picture grid stress in Texas, they picture the big metros. The Summer Power Index tells a different story.

Sherman-Denison, a North Texas metro of just 60,000 housing units, topped the index with a score of 68.9, ahead of Houston, Dallas-Fort Worth, San Antonio, and Austin. It wasn’t alone in punching above its weight: every one of the six most grid-stressed Texas metros was a smaller city. Houston didn’t appear until #7.

Two factors explain why these smaller metros climbed so high: rapid growth running ahead of infrastructure, and aging housing stock that was never built for today’s cooling demands. Wichita Falls is the clearest example of the housing-age problem. More than 3 in 4 homes in the area (76%) were built before 1990, the oldest housing stock of any metro in the rankings and nearly 20 percentage points above the state median. Older homes typically have weaker insulation and less efficient cooling systems, which translates to higher per-household demand on hot days.

The same logic works in reverse, which helps explain why some of the state’s biggest names landed lower than you might expect:

• Austin (#17) despite leading Texas in population growth at 12% since 2020. Newer construction did the heavy lifting, with 96% of Austin homes equipped with central AC and only 34% built before 1990.
• Dallas-Fort Worth (#11) despite ranking third in population growth statewide. Nearly 88% of DFW homes have central AC, and only 48% predate 1990, both of which softened the metro’s per-household exposure.

The pattern that emerges is consistent. Fast-growing metros with newer, better-cooled housing stock can absorb growth without pushing each household harder on the grid. Smaller, older metros usually can’t.

The Geography of Texas Summer Grid Stress

Housing and growth tell most of the story, but geography fills in the rest. Where a metro sits on the map shapes how much margin its grid has to work with and how households cool their homes in the first place.

The tradeoff is most visible in the North. Three of the four most grid-exposed metros (Lubbock, Wichita Falls, and Amarillo) sit inside ERCOT’s northern weather zone, which peaked at just 2,362 MW in 2024. That’s roughly one-twelfth the capacity of the North Central zone anchored by Dallas-Fort Worth, which peaked at 27,803 MW. A smaller zone with older housing and growing demand has less headroom to absorb a heatwave than the larger urban zones built for scale.

Move south to the Rio Grande Valley, and the strain shifts from grid capacity to home cooling. Four of the nine Texas metros where more than 1 in 4 homes lack central AC sit in this region:

• Brownsville-Harlingen (#5)
• Eagle Pass (#16)
• McAllen (#20)
• Laredo (#21)

Households in these metros often rely on window units, mini-splits, or no cooling at all. That can mean steeper bills, less consistent comfort, and harder choices on the hottest days.

El Paso shows the flip side of the AC story. The metro landed at the bottom of the index at #26 of 26, even though its summer climate is plenty hot. The reason is cooling technology: roughly 98% of El Paso homes use evaporative cooling instead of central AC, the highest rate in Texas. Evaporative coolers draw a fraction of the electricity that central AC does, which keeps El Paso’s per-household contribution to summer peak demand among the lowest in the state.

What This Means for Texas Households Heading Into Summer

The Summer Power Index reframes what grid stress actually looks like in Texas. The metros with the biggest names aren’t always the ones pulling the hardest per household, and the ones at the top of the rankings are often smaller cities with older homes and faster growth than the grid was originally built for. As summer demand keeps testing ERCOT’s limits, knowing where you sit on the map (and how your home contributes to the load) is one more piece of context Texans can use to plan ahead, manage usage, and keep monthly bills in check.

Methodology

About the Texas Summer Power Index

The Texas Summer Power Index is a per-household composite score (0 to 100) that ranks 26 Texas metropolitan statistical areas on their exposure to summer peak electricity demand. Each metro’s score is the simple average of three equally-weighted components, each independently normalized 0 to 100 across the 26-MSA universe. Higher scores indicate greater per-household exposure to summer peak demand.

Scoring components

The index equally weights three per-household factors:

1. Population growth, April 2020 to July 2024.
   U.S. Census Bureau Population Estimates Program, Metro Totals, vintage 2024. Faster growth
   increases a metro’s factor score. Source: Census.gov.
2. Share of housing stock built before 1990. U.S. Census Bureau American Community Survey, 5-Year estimates 2019 to 2023, table B25034. Older housing stock increases a metro’s factor score.
3. Share of homes without central AC. Harvard Dataverse Predicted AC Prevalence by CBSA and Census Tract, defined narrowly as window or wall units or no cooling at all. Higher no-central-AC share increases a metro’s factor score.

Each factor is normalized using min-max scaling: for each metro, (raw value minus minimum across 26 MSAs) divided by (maximum minus minimum), multiplied by 100. The composite score is the unweighted mean of the three normalized factor scores.

ERCOT as cross-reference context

ERCOT 2024 native load data is cross-referenced alongside each metro’s score at the weather-zone level and appears in the accompanying workbook and map. It is not used as a scoring component. ERCOT publishes peak demand at the weather-zone level, and Texas’s 26 MSAs are grouped into eight ERCOT zones, meaning multiple metros share a single zone peak. Using ERCOT peak as a scoring input would either (a) assign identical ERCOT scores to every metro in the same zone, adding no ranking
signal, or (b) divide zone peaks across metro housing in ways that produce artifacts when a single metro occupies an entire zone. ERCOT data therefore serves the index as geographic context, in keeping with the brief’s direction to cross-reference ERCOT data with metro population and housing AC data. Source: https://www.ercot.com/gridinfo/load/load_hist

Why per-household

All three scoring components are per-household rates, a growth rate, and two housing-stock shares. The index measures exposure intensity per resident, not absolute contribution to grid load. Total housing volume was deliberately excluded from the composite to prevent the largest metros from dominating the rankings on size alone. Absolute housing volume is retained in the workbook as a descriptive column for context.

The evaporative cooler decision

The “no central AC” component excludes evaporative coolers, which draw a fraction of central AC’s electricity and are common in dry-climate metros like El Paso. This is why El Paso ranks #26 of 26. Under a naive “not central AC” definition, El Paso would appear highly exposed, but 97.95% of El Paso homes use efficient evaporative cooling and are therefore not at elevated summer peak-demand risk. The Harvard AC data is a modeled estimate based on 2021 housing characteristics, calibrated to Census-reported occupied housing counts.

Known caveats

• The Texarkana MSA spans Texas and Arkansas; reported figures include both sides of the state line.
• Eagle Pass is assigned to ERCOT’s SOUTH weather zone as the best available approximation, as it was not included in ERCOT’s most recently published zone designations.
• Lufkin-Nacogdoches was reclassified from MSA to micropolitan and is not included in the rankings.
• ACS’s 5-year margin of error is not reported in this summary. For large metros, MOE is negligible; estimates for Eagle Pass and Sherman-Denison carry approximately 5 to 10% ranges.
• 1.8% of Texas census tracts (92 of 5,041) had multi-CBSA assignments in the Harvard source data. These were deduplicated to keep each tract in a single CBSA.
• Factor scores are normalized within the 26-MSA Texas universe used for this index and are not directly comparable to any other state or national ranking.

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