Ultracapacitors have been established as the energy storage medium of choice in wind power applications for many years. In 2006, Enercon first commercially integrated them with these systems for the purpose of pitch control and emergency power for these systems. Ultracapacitors proved to be superior to the incumbent battery systems, performing far beyond the batteries’ limitations. They are particularly beneficial in that they maintain a high level of performance in cold temperatures, require little to no maintenance, and have a very long cycle and calendar life. The capacitors are typically placed at schematic points in the pitch control system and the switched mode power supply serves as the charging circuit for the energy storage component, which subsequently powers the motor controllers. Ultracapacitors increase the limited choices of energy storage of a typical pitch control system and maximize efficiency.

At least two functioning systems are required to bring a wind turbine to rest, and a pitch control is a necessary safety feature for situations in which wind speeds are too high or grid connection to the wind turbine is lost. Ultracapacitors help create a more reliable system for these emergency type situations. This is because the power supply is located as part of the rotating assembly or stationary inside the hub, which limits your choice of energy storage. Ultracapacitors are lightweight yet solid, and have faster response times than heavier batteries which require a more significant structure to support their rotation and stave off negative effects of the cold. The requirements of ultracapacitors are much simpler. They only require some protection from moisture, inexpensive balancing circuitry and a designed charge or float voltage to maximize their life.