Changes

Oil shale is a class of [[sedimentary rock]] (not necessarily [[shale]]) that contains significant amounts of Kerogen, a waxy substance from which [[oil]] can be obtained through a process called pyrolysis. The worldwide oil reserves contained in oil shale are estimated to be in the region of three trillion barrels, but obtaining this oil is both economically and environmentally expensive [http://www.eia.doe.gov/oiaf/archive/aeo06/pdf/0383(2006).pdf] - a problem that has limited its use to date <ref name=aeo2006>

Oil shale is a class of [[sedimentary rock]] (not necessarily [[shale]]) that contains significant amounts of Kerogen, a waxy substance from which [[oil]] can be obtained through a process called pyrolysis. The worldwide oil reserves contained in oil shale are estimated to be in the region of three trillion barrels [http://www.eia.doe.gov/oiaf/archive/aeo06/pdf/0383(2006).pdf], but obtaining this oil is both economically and environmentally expensive - a problem that has limited its use to date <ref name=aeo2006>

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  | author = World Energy Council

  | author = World Energy Council