Mystery of 60-Second Fluctuations in Power Grids Solved

Researchers led by Dirk Witthaut traced brief, recurring dips in European grid frequency to large battery-storage systems that perform power checks at the start of each minute. The checks create small, simultaneous increases in electricity consumption. Because the timing is synchronized across many devices, their combined demand produces a distinctive signal in the grid. The team ruled out a single generator or consumer and identified the pattern by measuring electricity use at 80 locations on Forschungszentrum Jülich’s Living Lab Energy Campus. The same one-minute fluctuation appears beyond Europe, suggesting the phenomenon is global.

Although the deviations have not threatened grid security, they can make hydroelectric turbines briefly slow and then speed 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 signal’s strength quadrupled from 2016 to 2021. Researchers say the straightforward fix is to randomize when devices conduct their checks, instead of scheduling them all at the minute mark. Battery systems may not be the only synchronized appliances involved; digitally controlled equipment such as heat pumps, air conditioners, and household machines could contribute similar fluctuations. The findings show how routine, well-intentioned device operations can collectively affect power-system stability and equipment longevity.