A device and method for producing energy from a dilute VOC gas stream. The device includes a concentrator that concentrates a dilute VOC gas stream into a concentrated VOC fuel. The concentrated VOC fuel is supplied to the fuel intake of an engine. The device is operated by adsorbing the dilute VOC onto an adsorbing media within a concentrator. The concentrator increases the concentration of VOC per unit volume. The adsorbed VOC are then desorbed to form a concentrated VOC fuel stream. The concentrated VOC fuel stream may be either liquefied VOC or a more concentrated VOC gas stream. The concentrated VOC fuel stream is then directed to an engine to produce kinetic or electrical energy.