Researchers from Forschungszentrum Jülich, led by Dirk Witthaut, identified the cause of periodic electrical grid frequency drops occurring every 60 seconds globally. The investigation, commissioned by Tennet Germany, confirmed that the anomalies appear in data across Europe, Australia, the U.S., and Malaysia.
The team discovered that stationary battery systems, including those in data centers and grid-scale storage, perform state-of-charge checks every minute. Because these devices are internet-connected, their internal clocks synchronize, causing simultaneous, minute-long disturbances that aggregate into measurable frequency sags.
In Ireland, where data centers accounted for 18% of the electricity load by 2022, frequency drops increased from 3 mHz in 2016 to 12 mHz in 2021, with some recent events exceeding 20 mHz. While the grid is designed to handle swings of 200 mHz, these cumulative disturbances pose risks when combined with other loads.
To mitigate the issue, researchers recommend that manufacturers introduce randomization into the scheduling of battery charge checks. Similar periodic fluctuations were detected in IoT devices, though less than 3% of such hardware currently runs the latest firmware, complicating potential software-based fixes.
