Attribution and projection of regional winter wind energy drought in Europe

Abstract The decline of surface wind speed in many regions of the world is an important phenomenon as it is potentially expected to decrease wind power production. It is not clear, however, whether this decline takes the form of a gradual wind speed decrease or an increase in ‘wind energy droughts’ (WED), long periods with weak wind speeds. Both types of wind speed reductions contribute to a decline in wind power production. Prolonged and more frequent WED, in particular, may reduce revenue and jeopardize wind farm projects. Past and future changes in WED, as well as their underlying drivers, remain poorly understood. Here we show that winter WED will become more probable in Europe and the return period of 10.3 yr events during 1971–2000 have been shortened to about 10 yrs in the whole Europe, and it would be shortened to about 6.6 yrs during 2041–2070, under uncurbed greenhouse gases emission (scenario RCP8.5). In the current period, low wind energy winter has become more probable in most European countries, especially in the northern countries, showing a higher probability ratio of wind droughts. In the future, for some southern countries, the frequency of wind energy winter droughts is projected to decrease compared with the current period, which is helpful for the development of wind power generation in these countries. In addition, the changes in WED are sensitive to the global warming level. With global warming at 1.5 °C, 2 °C, 3 °C, 4 °C levels, low wind energy winter in Europe will occur more frequently as the probability is more than 1.13, 1.46, 1.53, 1.60 times as much as that in the current climate, respectively. The regional difference of attribution is meaningful for the optimization of wind energy transmission networks in Europe, which may be considered by large-scale wind energy producers.