A device and method for producing a reformate fuel from a hydrocarbon gas source. The invention enables the conversion of a dilute hydrocarbon gas into a more easily consumable reformate fuel. Gases having low concentrations of hydrocarbons are concentrated using a concentrator into a gaseous or liquid concentrated VOC fuel. The concentrated VOC fuel is then converted into a reformate using a reformer. The reformate is more easily consumed by an energy conversion device such as a combustion engine, fuel cell, sterling engine or similar device that converts chemical energy into kinetic or electrical energy. The reformer enables complex hydrocarbon fuels that are not normally suitable for use in an energy conversion device to be converted into a reformate. The reformate may be directly supplied into the energy conversion device.