The impact of sudden stratospheric warmings on electricity consumption and wind power generation in Finland

In Arctic countries, a large fraction of wintertime electricity consumption is used for heating spaces and, thus, the electricity consumption is highly sensitive to outside temperature variations. Also, the production of electricity by wind turbines depends directly on surface wind speed. Wintertime weather in Northern Europe is significantly influenced by the state of the stratospheric polar vortex, the westerly wind pattern circulating the polar region during winter. When the polar vortex is strong (weak), winter temperatures are more likely mild (cold) and surface wind speeds are higher (lower) in Northern Europe.

Sudden stratospheric warmings (SSWs) are, as the name implies, events where stratospheric temperature abruptly increases due to significant weakening or breaking of the polar vortex. This usually causes a sudden outbreak of cold and less windy weather in Northern Europe which can last for weeks. The occurrence probability of SSW events during the winter season is affected by several factors, e.g., the phase of the so called Quasi-Biennial Oscillation (QBO). During easterly QBO phase, characterized by equatorial stratospheric zonal winds flowing from east towards west, more planetary waves are guided to the polar stratosphere where they weaken the stratospheric polar vortex. As a result, the probability for SSW events is higher in easterly QBO phase compared to the westerly phase.

Here we study Finland’s electricity consumption and wind power generation separately in winters with and without an SSW in different QBO phases. We find that the electricity consumption is significantly higher in winters with SSWs compared to winters where an SSW does not happen, while the opposite is true for the wind power generation. We also evaluate the uncertainties of seasonal predictions of electricity consumption and wind power generation based on seasonal predictions of SSW probability.