Energy storage requirements to address wind energy variability

Aim of this contribution is to show the variability of wind farm capacity factors (the actual generation power vs the nominal power) to highlight the needs of energy storage. Low-frequency (monthly and annual values) cases are shown for wind farms in the continental United States, and high-frequency (5 minutes values) cases are shown for south east Australia (all of Australia excluding Western Australia and Northern Territory). In the United States, wind farms produce electricity on average over a year at a rate of around 30% to 35% of the capacity but with strong variability, seasonal and interannual, between different techno-resource group (TRG) areas for wind resource and within the same wind energy resource TRG area. In south east Australia, the annual average capacity factors from wind are around 30% to 35%. There are many days every month where the average capacity factors may exceed 60% but also drop below 10%, sometimes about 5%. The proposed results make even stronger the case for energy storage facilities, if integration with conventional energy resources is not welcomed.