Meteorological conditions during periods of low wind speed and insolation in Germany: The role of weather regimes

Abstract

Renewable power generation from wind and solar energy is strongly dependent on the weather. To plan future sustainable energy systems that are robust to weather variability, a better understanding of why and when periods of low wind and solar power output occur is valuable. We call such periods of low wind speed and insolation “Dunkelflauten”, the German word for “dark wind lulls”. In this article, we analyse the meteorological conditions during Dunkelflauten in Germany by applying the concept of weather regimes. Weather regimes are quasi‐stationary, recurrent and persistent large‐scale circulation patterns that explain multi‐day atmospheric variability (5–15 days). We use a regime definition that allows us to distinguish four different types of blocked regimes, characterized by high‐pressure situations in the North Atlantic‐European region. We find that Dunkelflauten in Germany occur mainly in winter when the solar power output is low due to the seasonal cycle of solar irradiance and wind power output drops for several consecutive days. A high‐pressure system over Germany, associated with the European Blocking regime, is responsible for most of the Dunkelflauten. Dunkelflauten during the Greenland Blocking regime are associated with colder temperatures than usual, causing higher electricity demand, and would present a particular challenge as space heating becomes electrified in the future. Furthermore, we show that Dunkelflauten occur predominantly when a weather regime is well established and persists longer than usual. Our study provides novel insight into the occurrence and meteorological characteristics of Dunkelflauten, which is essential for planning resilient energy systems and supporting grid operators to prepare for potential shortages in supply.

The climatological renewable energy deviation index (credi)

“…Finally, short-term events, e.g. Dunkelflautes, can pose significant risk to highly renewable energy systems [12,[41][42][43][44]. A 8-day window for CREDI aligns with previous work [33], and is investigated here, see SI section D for additional figures and the top 50 eight-day events.…”

Using power system modelling outputs to identify weather-induced extreme events in highly renewable systems

“…With increased reliance on variable renewables and balancing via transmission and energy storage, this paradigm breaks down. In particular, the most critical events to system design extend beyond a single hour or day, and identifying such periods no longer depends only on weather data but also power system parameters including storage and transmission [7,20,44,45].…”

“…All costs are in 2013 EUR, but derive from model shadow prices, not actual market prices. [19,40,45]. Power systems based on renewables are primarily wind-dependent in the winter, especially in the northern latitudes [47], making them prone to 'wind droughts' .…”

Multi‐model assessment of sub‐seasonal predictive skill for year‐round Atlantic–European weather regimes

“…In addition, it is important to highlight that understanding the impacts of regimes on surface weather variables is as important as (or even more important than) understanding large‐scale flow situations (Bloomfield et al ., 2021), especially for economic sectors. For example, studies have shown that in winter there is an overproduction of wind power under cyclonic regimes (Grams et al ., 2017), whereas EuBL and GL blocking events are associated with periods of low electricity production by renewable sources (wind power and solar) and high electricity demand that lead to stress on the electricity system (Mockert et al ., 2022; Otero et al ., 2022). In this context, improving the skill for wintertime EuBL is thus crucial for better preparedness for those critical situations.…”