A wind turbine 10 temperature control system for maintaining the temperature of an energy storage device 50, which comprises, a power supply 30, a generator 15 and a breaking 40 resistor, commonly referred to as chopper, loading, attenuation or absorption resistor. The generator is in occasional electrical contact with the breaking resistor whereby a first current flows through the breaking resistor and excess kinetic energy of the generator is converted to heat and the power supply is configured to cause a second current to flow through the breaking resistor whereby the heat generated by the breaking resistor is provided to the energy storage device. Preferably the system includes control circuitry 55 arranged relative to the breaking resistor, a fan 60, switching means 16 & 35, a processor 70, a temperature sensor 80 and an enclosure, pitch box or axis cabinet 20 to facilitate housing of the system components.
