Today I Learned: Fugitive Emissions

The IPCC (Intergovernmental Panel on Climate Change) defines fugitive emissions as emissions that are not produced intentionally by a stack or vent, and stipulates that they may include leaks from industrial plants and pipelines [IPCC, 2006]. Potential sources of fugitive emissions maybe be caused by production, processing, transmission, storage, and use of fuels and include combustion emissions only if they do not meet production needs (e.g. natural gas flaring at gas and oil production facilities). 

The exact definition of fugitive emissions may vary from one sector to another. In practice, they generally include accidental emissions (pipeline breakage, coal seam fire, etc.), leaks and diffuse escapes (defective valves or seals, migration of gas to the surface near wells or mines, emissions from abandoned wells, etc.) and unintentional but non-productive discharges (mine ventilation, flaring, degassing, etc.). Many phenomena are therefore involved in a category that is primarily negative: fugitive emissions are ultimately emissions related to human activities that do not fit into any other category. 

The term "fugitive" is used because these emissions are not taken into account and calculated during the design of equipment and components. In addition, these emissions are unanticipated; as such, they are not detected by typical monitoring and control devices.  

Their very nature makes fugitive emissions difficult to quantify. There is no comprehensive global data, but it is possible to assess their significance and evolution by combining inventories and secondary data. Under the United Nations Framework Convention on Climate Change, industrialised countries  regularly report fugitive emissions. These inventories show stable emissions since the mid-2000s after a decline in the early 1990s and a rebound around 2000. In 2016, fugitive emissions reported by industrialised countries were 1.33 billion tonnes CO2 equivalent compared to 1.57 in 1990, about 85% of which were from the hydrocarbons sector, 15% from coal and a fraction from industry (UNFCCC GHG data).