Electricity consumption is highly dependent on outside temperatures in regions where electricity is used for heating, for example in northern Europe during winter. Wind power generation also heavily depends on weather conditions, which affect wind speed. Winter weather in northern Europe is influenced by the polar vortex, a strong westerly wind dominating the wintertime polar stratosphere. The polar vortex can temporarily collapse during sudden stratospheric warming (SSW), which is often followed by cold and windless weather in northern Europe, including Finland. In this paper, we examine the influence of SSWs on wintertime electricity consumption and wind power generation in Finland. We show that cold temperature and low wind speed anomalies are more often observed in winters when an SSW happens and the so-called quasi-biennial oscillation (QBO) of equatorial stratospheric winds is in the easterly phase. These changes are associated with higher electricity consumption and lower wind power generation. In contrast, winters without an SSW tend to have warm temperature and high wind speed anomalies, and thus, lower electricity consumption and higher wind power generation. When the probability of an SSW event is known, the results of this study show that it is possible to predict winter electricity consumption and wind power generation several months in advance.