▁this ▁chain ▁is ▁currently ▁about ▁ 1 % ▁While ▁this ▁may ▁compare ▁unf avor ably ▁to ▁solar ▁cells ▁combined ▁with ▁an ▁electric ▁drive ▁train , ▁b iod ies el ▁is ▁less ▁cost ly ▁to ▁deploy ▁( sol ar ▁cells ▁cost ▁approximately ▁US $ 2 5 0 ▁per ▁square ▁meter ) ▁and ▁transport ▁( elect ric ▁vehicles ▁require ▁batter ies ▁which ▁currently ▁have ▁a ▁much ▁lower ▁energy ▁density ▁than ▁liquid ▁fu els ). ▁A ▁ 2 0 0 5 ▁study ▁found ▁that ▁b iod ies el ▁production ▁using ▁so y beans ▁required ▁ 2 7 % ▁more ▁foss il ▁energy ▁than ▁the ▁b iod ies el ▁produced ▁and ▁ 1 1 8 % ▁more ▁energy ▁using ▁sun flow ers . ▁ ▁However , ▁these ▁statistics ▁by ▁themselves ▁are ▁not ▁enough ▁to ▁show ▁whether ▁such ▁a ▁change ▁makes ▁economic ▁sense . ▁Add itional ▁factors ▁must ▁be ▁taken ▁into ▁account , ▁such ▁as : ▁the ▁fuel ▁equivalent ▁of ▁the ▁energy ▁required ▁for ▁processing , ▁the ▁yield ▁of ▁fuel ▁from ▁raw ▁oil , ▁the ▁return ▁on ▁cultiv ating ▁food , ▁the ▁effect ▁b iod ies el ▁will ▁have ▁on ▁food ▁prices ▁and ▁the ▁relative ▁cost ▁of ▁b iod ies el ▁versus ▁pet rod ies el , ▁water ▁poll ution ▁from ▁farm ▁run - off , ▁soil ▁de ple tion , ▁and ▁the ▁external ized ▁costs ▁of ▁political ▁and ▁military ▁inter ference ▁in ▁oil - produ cing ▁countries ▁intended ▁to ▁control ▁the ▁price ▁of ▁pet rod ies el . ▁ ▁The ▁debate ▁over ▁the ▁energy ▁balance ▁of ▁b