Researchers have traced recurring power grid frequency drops to synchronized battery monitoring systems, solving a mystery affecting electricity networks worldwide. The disturbances occur every 60 seconds and have been detected across Europe, North America, Australia and parts of Asia.
Dirk Witthaut and colleagues at Germany’s Forschungszentrum Jülich investigated the phenomenon after transmission operator TenneT Germany raised concerns. Their research, published in Nature Energy, identifies periodic activity in battery-based uninterruptible power supplies (UPS) as a major cause.
The findings suggest that relatively small electrical fluctuations can become measurable across entire power networks when many devices operate at the same time.
How Battery Systems Cause Power Grid Frequency Drops
Electricity grids must maintain stable frequencies, typically 50 or 60 hertz, by balancing power generation and consumption. Unexpected changes in electricity demand can cause frequency fluctuations.
Researchers initially investigated hydropower turbines, which can produce low-frequency oscillations through mechanical resonance. However, those effects could not fully explain the precise 60-second pattern.
The team then installed more than 80 power-quality meters at the Jülich research campus. Measurements revealed recurring power fluctuations in buildings equipped with battery-backed UPS systems.
Many UPS systems perform scheduled battery checks every minute. Network time services can synchronize their clocks, causing multiple devices to adjust power consumption simultaneously.
Each fluctuation is small, but synchronized activity across thousands of installations can produce detectable grid-wide disturbances.
Ireland’s Data Centers Reveal Growing Disturbances
Irish electricity data provided additional evidence. Data centers accounted for approximately 18% of Ireland’s electricity demand in 2022, making backup battery installations particularly relevant.
Researchers found that recurring frequency drops increased from approximately 3 millihertz in 2016 to 12 millihertz in 2021. More recent measurements recorded individual drops exceeding 20 millihertz.
These disturbances have not reached safety-critical levels on their own. However, they can compound other grid fluctuations, increasing the importance of monitoring and prevention.
The findings add another dimension to electricity infrastructure challenges associated with growing data center energy demand.
Software Changes Could Reduce Grid Disturbances
The researchers recommend adjusting battery monitoring schedules so devices do not perform their checks simultaneously. Randomized timing or adaptive scheduling could reduce synchronized electricity demand without requiring major hardware changes.
The team reported that one manufacturer had already introduced a software update that partially reduced the periodic behavior.
Researchers also detected recurring power fluctuations in other connected devices, including smart appliances and Raspberry Pi systems. However, updating such equipment can be difficult because firmware maintenance varies by manufacturer and user.
Previous IEEE research on IoT firmware security provides additional context for the challenges of maintaining connected devices.
The study suggests that manufacturers and electricity network operators should coordinate device control schedules before synchronized demand becomes a larger stability concern. While the immediate disturbances remain manageable, expanding battery storage and connected infrastructure could increase their effects.
