  In the transition to a renewable energy system, the occurrence of
low-wind-power events receives increasing attention. We analyze the frequency
and duration of such events for onshore wind power in Germany, based on 40
years of reanalysis data and open software. We find that low-wind-power events
are less frequent in winter than in summer, but the maximum duration is
distributed more evenly between months. While short events are frequent, very
long events are much rarer. Every year, a period of around five consecutive
days with an average wind capacity factor below 10% occurs, and every ten years
a respective period of nearly eight days. These durations decrease if only
winter months are considered. The longest event in the data lasts nearly ten
days. We conclude that public concerns about low-wind-power events in winter
may be overrated, but recommend that modeling studies consider multiple weather
years to properly account for such events.
