Ultracapacitor Energy Storage System

Energy Storage Requirements

  • 6 cells in series, 3000F 2.7V cells, Operating at 2.42V/cell
  • 500F Module (6 modules per axis)
  • IEC 60529, IP20 - No exposed PCBA's


  • Passive balancing system
  • Turn-off voltage @ 2.4V per cell


  • GE 20Nm uses 4 ultracapacitor modules, same charger box (CCU)
  • Mounting bracket hardware for charger box CCU (not shown) - TBD

Value Proposition

Lower Maintenance Cost

  • Retrofit is a drop-in replacement
  • Retrofit interfaces with the existing Emergency Power Unit (EPU) and Turbine controller (SCADA System)
  • Eliminates costly maintenance and battery replacements
  • Reduces battery related pitch faults

Increased Reliability

  • Approximately 10-15 year life
  • Wider operating temperature range -40°C to +65°C
  • Minimizes turbine downtime

Improved Safety

  • Reduces operational safety concerns
  • Can be fully discharged to provide safer working conditions
  • Reduces number of climbs for technicians
  • No lead or acid
  • No change to lock-out tag-out procedures
  • IP20 rated - No exposed PCBA's

Ultracapacitor Module

  • The 6 cell capacitor modules are the same dimensions and use the same mounting locations as the batteries
  • Each blade pitch system will use 6 modules for GE30Nm and 4 modules for GE20Nm
  • LiCAP ultracapacitor modules feature laser welded bus bar connections to ensure a robust and reliable connection for the life of the installation VS. threaded cells with nuts that can be over torqued or come loose over time
  • Loose nuts can cause higher resistance which can lead to increased temperatures at the terminal. Increased temperature can shorten life and/or lead to failure of the module.

LiCAP Activated Dry Electrode®:

  • Lower ESR, since binder is non-conductive.
  • Higher capacitance. Since we use less binder, we can add more carbon in the mixture, which results in higher capacitance.
  • Note : Activation also enables finer binding fibers and higher fiber quantity, so we achieve the same strength electrode as the other dry method.

Windurance Capacitor Charging Unit (CCU)

  • The Windurance CCU is designed to monitor and manage 4 or 6 ultracapacitor modules
  • 1 Charging Unit per blade pitch actuator vs. 1 per ultracapacitor module. A cost-effective solution.
  • Fewer parts + fewer connections =higher reliability
  • The CCU can be used either for GE30Nm or GE 20Nm interchangeably.
  • Drop-in replacement conveniently interfaces to existing cables, harnesses and RS-485 communication protocol.
  • IP20 rated – no exposed PCBA’s.

Windurance Capacitor Charging Unit (CCU) 710-70004

  • Robust Electrical Design: The Windurance CCU design ensures reliable operation under extreme conditions.
      - The tests conducted in development exceed the IEC standards as follows:
         - IEC 61000-4-2 Electrostatic discharge immunity test - Level IV+
          - IEC 61000-4-4 Electrical fast transient/burst immunity test - Level IV+
         - IEC 62000-4-5 Surge immunity test - Level IV+
  • Universal: The Windurance CCU serves all 20Nm and 30Nm configurations without modification, enabling fleet-wide compatibility for streamlined inventory management.
  • Lightning Strike Protection: Our CCU is certified to IEC 62305-1 Edition 2.0, 2010.
  • Wide Operating Voltage Range: To protect against fluctuations in supply line voltage that can be common in remote locations, the CCU is designed and tested to operate from 40% low to 30% highline continuously. The CCU retains full charging capability down to 10% below nominal line voltage and continues to communicate all the way down to 40% below nominal.
  • Ultracapacitor Monitoring: The CCU can monitor individual module voltages and total string voltage. Any ultracapacitor module low voltage condition is communicated to the wind turbine controller for action.
  • Charge time: The CCU can charge the ultracapacitor string in one blade from 0V in 45 minutes (30Nm) or 40 minutes (20Nm). Both versions can recharge completely within 5.5 minutes after a single pitch event, worst case.