化石燃料[kasekinenryou] fossil fuel
可燃[kanen] inflammable
可燃性[kanensei] combustibility
可燃物[kanenbutsu] combustibles
核燃料[kakunenryou] atomic fuel

再燃[sainen] recurrence
代燃車[dainensha] car running on substitute fuel
内燃機関[nainenkikan] internal-combustion engine
燃える[moeru] to burn
燃え移る[moeutsuru] (of fire) to spread