Fuel is any material that is capable of releasing energy when its chemical or physical structure is altered. Fuel releases its energy either through chemical means, such as burning, or nuclear means, such as nuclear fission or nuclear fusion. An important property of a useful fuel is that its energy can be stored to be released only when needed, and that the release is controlled in such a way that the energy can be harnessed to produce work.

Fugitive emissions monitoring system contains machine readable elements at each fugitive emissions source. These machine readable elements are for identifying the source. The system also has a portable monitor that includes a reader, a detector, and storage. Specifically, the reader reads the machine readable element and generates a machine storable source identification signal corresponding to the element. The detector generates a second machine storable signal. This signal represents the amount or other attribute of fugitive emissions from the fugitive emissions source.