Abstract: The gear box in conventional wind turbine systems is very complex, large, heavy and costly. In addition, large, heavy, complex and costly lube oil systems are required to remove heat generated by such gear boxes. Such complex systems require frequent maintenance and overhaul, requiring access even in offshore locations. A solution to these problems has been identified in the art by eliminating the requirement for a gear box and lube oil system by the invention of direct drive generators which generate at 50 Hz frequency at wind turbine speed, having a very large number of poles and being larger and heavier than the traditional four pole equivalents. The present invention includes a energy storage and recovery system whereby a wind turbine generates electricity at a predetermined frequency below 45 Hz which may then be used to compress air for subsequent expansion and generation of electricity at a grid frequency of 50 Hz.