Gases occurring in underground deposits, whether liquefied or gaseous, consisting mainly of methane.

It includes both 'non-associated' gas originating from fields producing hydrocarbons only in gaseous form, and 'associated' gas produced in association with crude oil as well as methane recovered from coal mines (colliery gas) or from coal seams (coal seam gas). It does not include gases created by anaerobic digestion of biomass (e.g. municipal or sewage gas) nor gas works gas.

• Regulation (EC) No 1099/2008 of the European Parliament and of the Council of 22 October 2008 on energy statistics
  Place of publication: (Dz. Urz. UE L 304 z 14.11.2008, str. 1, z późn. zm.)