For over a decade, researchers worldwide could not explain one of the most puzzling anomalies in global energy: isolated power systems across different continents were synchronously altering their alternating current frequency exactly every 60 seconds. Neither geographical proximity nor shared transcontinental power lines could explain such a precise match. The answer, as it turned out, was banal to the point of being a joke—automatic self-checks of uninterruptible power supplies (UPS) synchronized via the internet. The results of the study, published in the scientific journal Nature Energy, put an end to a long-standing debate while simultaneously opening up a new class of systemic risks associated with the mass proliferation of "smart" equipment.
From Scandinavian Anomalies to a Global Problem
The first recorded instances of minute-by-minute frequency fluctuations appeared in Scandinavian power grid data back in 2014. Operators at the time attributed the anomaly to measurement equipment errors or local dispatch operations. However, a few years later, similar patterns were discovered in the grids of continental Europe, Great Britain, Australia, and the USA—systems that are physically disconnected from one another and managed by independent dispatch centers. The coincidence of the periodicity at exactly one minute in the complete absence of direct electrical connection between continents made it obvious that researchers were facing not a local, but a systemic phenomenon requiring a fundamentally different explanation.
Cologne Scientists and Data from Jülich
The solution was proposed by a research team led by Dirk Witthaut from the University of Cologne. To identify the source of the fluctuations, the researchers analyzed high-precision electricity consumption measurements at the Jülich Research Centre (Germany), where the smallest load changes are recorded with sub-millisecond resolution. The analysis showed that every single minute, a microscopic yet statistically significant load "pulse" enters the grid, the character of which corresponds to the self-diagnostics mode of backup power sources. The key observation was that modern digital devices synchronize their internal clocks via internet protocols (NTP), causing thousands of UPS units in hospitals, data centers, and industrial enterprises to perform self-checks at the exact same second.
Why the Power Grid Reacts to Millions of Watts
The power grid operates on the principle of a constant dynamic balance between generation and consumption. When total consumption exceeds generation, the alternating current frequency (50 or 60 hertz depending on the region) decreases; when generation prevails, it increases. Even a microscopic yet synchronous load surge from thousands of devices switching to test mode simultaneously creates a short-term imbalance in the grid, which dispatch systems record as a frequency deviation. The amplitude of these fluctuations is only a few millihertz, which is orders of magnitude smaller than allowable deviations, so they do not yet pose a direct threat to the stability of energy supply. Nevertheless, the very fact of a hidden, repeating disturbance source in the global energy system is a subject of serious attention from grid operators.
The Solution That Cost One Line of Code
Eliminating the anomaly proved radically simple compared to decades of searching. Equipment manufacturers only need to modify the UPS software by adding a random time offset (jitter) to the self-diagnostics timing. This will stagger the checks of thousands of devices over time and remove the synchronous "shock" to the grid. Notably, already at the stage of publishing the results, at least one major UPS manufacturer, upon receiving an appeal from scientists, released a firmware update in which the strict 60-second check periodicity was replaced with a randomized interval. According to researchers, the mass deployment of such patches in the coming months should completely eliminate the recorded anomaly in all affected regions.
Broader Context: A Lesson for the Era of "Smart" Grids
The story of minute-by-minute frequency fluctuations is a clear example of how the mass proliferation of digital devices with network synchronization creates new, unforeseen classes of systemic effects in infrastructure designed in the era of analog technologies. Researchers emphasize: minor routine equipment checks, if they occur synchronously on the scale of millions of devices, can trigger system failures even if each individual element is operating normally. In conditions where by 2030 the share of "smart" consumers and generators in the power grids of most developed countries will exceed 50%, the task of deciphering and desynchronizing automatic cycles is becoming not an academic, but a practical issue of energy supply security.
