Hottest July Ever Stresses Aging Transformer Fleets

Extreme temperatures stress electrical grid and accelerate transformer issues, but monitoring can help detect issues before failure occurs

VALENCIA, California – August 20, 2026, Power grids worldwide are under compounding stress as climate change elevates temperatures and exacerbates weather patterns, stretching and often exceeding the capacity of an already fragile, aging infrastructure. According to the United States National Oceanic and Atmospheric Administration, July 2026 tied 2024 as Earth’s hottest July, with the planet’s temperature 2.12 degrees Fahrenheit (1.18 degrees Celsius) above the 20th-century average.

Importantly, weather accounts for roughly 80% of major power outages in the United States,1 and weather outages are on the rise. Additionally, the peak of hurricane season is just weeks away, and forecasters have noticed an uptick in potential storms lurking in the Atlantic.

Adding to the likelihood of weather-related outages, the average large power transformer in service today is 40 years old, or precisely at the age where failure probability rises sharply. H2scan, a developer of systems that monitor health across transformer fleets, is urging operators to assess transformer health now, while there is time to implement proactive changes that can help counteract extreme conditions caused by these challenging conditions.

David Ellis, H2scan Board CEO, said, “Transformers don’t fail because of one bad day; they fail because accumulated stress goes undetected. Rising temperatures globally and increasingly severe weather patterns multiply stress, and operators who act now can identify developing faults in their equipment before they fail.”

The confluence of factors should create a sense of urgency. Transformer reliability follows a “bathtub curve,” meaning after a long, stable service period, failure probability rises sharply once a unit passes 30 to 40 years, exactly where most of the world’s fleet sits today. This known factor, combined with stress from climate change, accelerates the speed of that bathtub curve.

How Heat and Grid Stress Age Transformers

Liquid-filled transformers rely on kraft paper and mineral oil insulation, both of which degrade faster under thermal stress:

  • For every 8°C above design temperatures, paper insulation service life is cut in half
  • For every 10°C rise in top oil-temperature, oil oxidation rate doubles
  • Doubling moisture content in paper insulation halves transformer life
  • Oil oxidation byproducts form sludge that impairs both dielectric strength and heat transfer

Key Actions for Transformer Operators

H2scan engineers recommend the following steps during periods of elevated grid stress:

  • Monitor top oil-temperature continuously, treating sustained time in excess of 8°C above design recommendations as an active aging event
  • Verify all cooling equipment — fans, pumps and radiators — is fully operational before peak load periods
  • Repair gasket leaks promptly, as moisture ingress is a primary aging accelerant
  • Where continuous hydrogen monitoring is deployed, analyze the data to assess transformer health and take corrective action when problems are identified

Continuous Monitoring Where Failure Has the Highest Consequences

Electric utility transformers provide critical power during weather events. A transformer failure can threaten hospitals, emergency services, and residential customers who depend on power for medical equipment.

That’s why operators sample transformer oil for dissolved gases like hydrogen that are predictive of transformer failure. Manual oil samples are typically performed annually, but sensors like H2scan’s GRIDSCAN® 6000 Multi-Sense Monitors continuously monitor dissolved gas, providing early warning before faults create service interruptions.

H2scan’s GSAO Control Hub series complements continuous hydrogen monitoring by correlating hydrogen readings with load current and top-oil temperature data, turning a single reading into a richer diagnostic picture that distinguishes normal variation from a genuine developing fault.

About H2scan

H2scan, a pioneer in the development of hydrogen sensing technology, has been at the forefront of innovation for over two decades. Building on a strong foundation of research and development, H2scan has established itself as the preferred provider of leading hydrogen sensors, analyzers and systems. The operating life of their sensors surpasses that of other commercially available systems, and the company’s new Gen.5 solutions with self-calibration offer unparalleled accuracy, maintenance-free operation and cost-effectiveness.

Trusted by industry giants like ABB, ExxonMobil, NASA and others, its products are integral in shaping the new Hydrogen Economy for a clean, secure and affordable energy future. H2scan products are also used by power utilities for transformer fleet monitoring, by the petroleum and chemical industries to optimize hydrogen-based processes, and for safety monitoring in enclosed areas susceptible to hydrogen leaks.

Built on solid-state technology pioneered at Sandia National Laboratory and the U.S. Department of Energy, H2scan holds 44 patents covering its core technology, software and product innovations. For more information, visit www.h2scan.com.

 

Media Contact:
Kriston Costello
Marketing Specialist, H2scan
[email protected]

 

  1. https://www.climatecentral.org/climate-matters/weather-related-power-outages-rising
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