Large-scale battery storage systems check their charge every 60 seconds, causing

A research team led by Dirk Witthaut at Forschungszentrum Jülich traced brief, highly regular dips in European grid frequency to large-scale battery storage systems. Transmission operator Tennet had recorded the fluctuations every 60 seconds for years, but their precise timing suggested a clock-controlled cause: many devices must be drawing power at once. Measurements at 80 locations on Jülich’s Living Lab Energy Campus revealed matching consumption spikes at sites with battery systems. Examining one system showed that its electricity use rose at the start of each minute while it checked its state of charge. The researchers found the pattern is global, not unique to Europe.

The likely explanation is that manufacturers independently chose the same convenient check time because there are no binding standards for these tests. Synchronized checks create short demand surges that make grid frequency dip; hydropower turbines respond by slowing and speeding up, increasing wear. The effect may grow as battery storage expands: in Ireland, where data centres with large batteries account for about a fifth of electricity demand, the one-minute signal’s amplitude quadrupled from 2016 to 2021. The team proposes a simple remedy: randomize when batteries perform checks rather than starting them together. Other digitally controlled equipment, including heat pumps and air conditioners, could also produce synchronized patterns, so batteries may not be the only contributor.