A system for cooling a storage area of a vehicle includes one or more eutectic plates (102) for cooling the storage area (101); a refrigeration system (103) configured to cool the one or more eutectic plates (102); an electrical system (106) configured to receive electrical power from a mains power supply and supply electrical power to the refrigeration system (103); a variable displacement hydraulic pump (113) having an input shaft for being driven by an engine (112) of the vehicle (100); and a generator (107) configured to receive hydraulic fluid from the hydraulic pump (113), generate electrical power in response thereto and supply the electrical power to the refrigeration system (103); the hydraulic pump (113) is configured to reduce the volume of hydraulic fluid that it supplies to the generator (107) for each rotation of the input shaft, as the rotational speed of the input shaft increases.