The team installed measuring points on end devices at a total of 80 locations – and sure enough, the same periodic pattern in electricity consumption was observed precisely at the locations where large-scale battery storage systems are designed to ensure an uninterrupted power supply. “We took a closer look at one of them and found a spike in electricity consumption at the start of every minute due to the power check,” explains Witthaut.

As there are no binding standards for such power checks, Witthaut suspects that most battery manufacturers assumed that a 60-second interval would be sensible. The start of every minute was simply chosen as the test time. “It is entirely possible, however, that battery storage systems are only part of the problem here,” says Witthaut. “It cannot be ruled out that other digitally controlled appliances – such as air-conditioning systems, heat pumps, washing machines, and dishwashers – may also exhibit similar patterns.”

Reminds me of when I did DSL customer service. Once every few months we’d get a customer (never the same one twice) calling up saying that their connection was terrible, and when we checked the logs, their connection would dropping at incredibly regular intervals aligned well with human units of time. On the hour (or a few minutes past) every hour, for example, or every 10 minutes.

We figured, and told them, that it had to be something on a timer causing an EMP or other interference at their end because there ought to be nothing outside their premises acting with such specific regularity.

The caller usually went away and we’d see the connection stabilise not long after, leaving us none the wiser, but hey, fixed!