Wind resource droughts in China

Abstract

With the rising share of wind energy in power generation, the occurrence of low-wind-power events (termed “wind resource droughts”) are becoming critical to understand for the national electricity supply and security of power systems. We use hourly wind speed data (2428 meteorological stations; in the years 2010-2020) to analyze the occurrence of wind resource droughts in seven onshore wind energy planning regions over China. We find that wind resource droughts tend to occur in warm season (summer and autumn) in most regions (i.e., Northeast China, East China, Central China, South China and Tibetan Plateau). In these regions, the number of moderate wind resource drought events (wind capacity factor below 10%) in warm season (summer and autumn) was about 3-13 times higher than cold season (spring and winter). By contrast, for North China and Northwest China, the wind resource droughts mainly occurred in autumn and winter. Averaged over 11 years, Northeast China experienced the most moderate wind resource droughts with 30 days per year, while Northwest China had only 1 day per year. Some of these wind resource drought events occurred consecutively, in which Northeast China experienced 9 wind resource drought events that lasted for at least five days (where the longest reached 9 days) across the 11 years from 2010 to 2020; North China and South China exhibited 1 five-day wind resource drought events; while Northwest China, East China, Central China and Tibetan Plateau had none. Moreover, we found that increasing the aggregated area of wind resource can reduce volatilities of the wind energy. Therefore, improving the cross-regional transmission capacity can substantially help reduce the number of wind resource drought events. These findings should assist decision-makers to establish the counterplan to mitigate the energy shortages and instability in power supply caused by the uncertainty of wind resource droughts.