Summer heat waves and winter storms create a dual-season threat that can strain grid reliability.
Heat and Severe Storm Reliability Stress
Texas operates the only major power grid in the continental United States that is not interconnected with the Eastern or Western grids. The Electric Reliability Council of Texas manages electricity for roughly 26 million customers, covering about 90% of the state's electric load.
This isolation became the defining factor during Winter Storm Uri in February 2021, when frozen natural gas infrastructure and surging heating demand triggered cascading failures. ERCOT ordered 20,000 MW of load shedding, the largest controlled blackout in U.S. history, leaving more than 4.5 million homes and businesses without power for up to four days.
The Texas grid faces a dual-season stress pattern: summer heat waves push cooling demand to record levels, while winter storms expose weatherization gaps that Uri revealed. Backup sizing in Texas cannot default to a single season. Planning should account for both extended summer cooling loads and multi-day winter heating scenarios where grid recovery may take significantly longer than in states with interconnected grids.
Federal disaster declaration for severe winter weather causing widespread power outages and infrastructure disruption across Texas.
Source: FEMA DR-4586Major disaster declaration for catastrophic flooding and wind damage, primarily in the Houston metro area.
Source: FEMA DR-4332NRI top hazard is Heat Wave, but Fire leads FEMA declarations with 17 of 37 total — a cross-signal worth noting.
Keep outage duration conservative, but add buffer for repeated summer events.
Core household loads for a short-duration event: refrigeration, medical support, and communications.
Load
338W
Target
12h
Minimum
6,700 Wh
Covers most non-major weather events. Check surge compatibility for the refrigerator compressor.
Size this scenario in calculatorFull critical-load bundle for a longer disruption, adding air circulation for comfort.
Load
421W
Target
24h
Minimum
16,700 Wh
For events beyond 24 hours, add solar or a second battery to extend coverage.
Size this scenario in calculatorCritical Note: No single portable power station in our database covers the full 12-hour baseline at this load (6,144 Wh max). Use solar recharge, load rotation, or expandable systems for longer events.
Undersizing for cooling-season outages when heat-wave demand can strain local infrastructure.
Assuming one hazard profile statewide even though storm and heat exposure vary widely by region.
Skipping surge headroom for compressor loads like refrigerators and portable AC units.
For home backup, you need surge capacity for fridge compressors and enough Wh for multi-day outages. Here are the best options from our database of 33 stations.
Inverter ACs draw up to 710W running. Standard ACs surge to 2,010W at startup. Here is exactly which power stations can run each type, with OEM data.
A french door fridge draws 195-207W with a 40% duty cycle. Here's how long your power station will keep it cold, with real numbers from OEM-verified models.
Composite score: 91.0 / 100
Rating: Relatively High
Top modeled hazards: Heat Wave, Tornado, Hail
Hurricane score: 76.0
Winter Weather score: 80.0
Wildfire score: 83.5
Total (2014-2023): 37
Most recent: 2023-04-21 Winter Storm
| Type | Count |
|---|---|
| Fire | 17 |
| Flood | 7 |
| Hurricane | 4 |
| Biological | 3 |
| Severe Storm | 3 |
| Severe Ice Storm | 2 |
| Winter Storm | 1 |
Required Wh = (Total Load W × Target Hours / Inverter Derate) × Safety Factor
Inverter derate: 0.70 (30% real-world loss)
Safety factor: 1.15
Rounding: Up to nearest 100 Wh
Texas has an NRI composite risk score of 91.0 (Relatively High), with 37 federal declarations from 2014 to 2023. NRI top hazard is Heat Wave, but Fire leads FEMA declarations with 17 of 37 total — a cross-signal worth noting.
For the primary scenario on this page (Essential 12-hour backup), the estimated minimum is 6,700 Wh for a 12-hour target. Refine this in the calculator with your actual devices.
NRI is a modeled risk index based on hazard exposure, vulnerability, and expected loss. FEMA declarations reflect federally declared incidents. They answer different questions — use both signals together for planning.
Planning only for winter events and missing the impact of summer heat and severe storm clusters. See the common mistakes section above for more state-specific pitfalls.
