Ultracapacitors have been established as the energy storage medium of choice in wind systems. Enercon first commercially integrated them in 2006 for the purpose of pitch control and emergency power for the pitch control systems. Ultracapacitors proved superior to the incumbent battery systems by performing beyond the limitations of the batteries. In particular, ultracapacitors maintain a high level of performance in cold temperatures and have a very long cycle/calendar life while generally requiring no maintenance.