▁oil ▁( W VO ); ▁ ▁Animal ▁f ats ▁including ▁t allow , ▁l ard , ▁yellow ▁gre ase , ▁ch icken ▁fat , ▁and ▁the ▁by - products ▁of ▁the ▁production ▁of ▁Om ega - 3 ▁fat ty ▁ac ids ▁from ▁fish ▁oil . ▁ ▁Al ga e , ▁which ▁can ▁be ▁grown ▁using ▁waste ▁materials ▁such ▁as ▁se w age ▁and ▁without ▁disp la cing ▁land ▁currently ▁used ▁for ▁food ▁production . ▁ ▁O il ▁from ▁hal oph y tes ▁such ▁as ▁Sal ic orn ia ▁big el ov ii , ▁which ▁can ▁be ▁grown ▁using ▁salt water ▁in ▁coast al ▁areas ▁where ▁conventional ▁cro ps ▁cannot ▁be ▁grown , ▁with ▁yields ▁equal ▁to ▁the ▁yields ▁of ▁so y beans ▁and ▁other ▁oil se eds ▁grown ▁using ▁fresh water ▁ir rig ation ▁ ▁S ew age ▁Sl ud ge ▁– ▁The ▁se w age - to - bio f uel ▁field ▁is ▁attract ing ▁interest ▁from ▁major ▁companies ▁like ▁W aste ▁Management ▁and ▁start ups ▁like ▁Info S pi , ▁which ▁are ▁bet ting ▁that ▁renew able ▁se w age ▁b iod ies el ▁can ▁become ▁compet itive ▁with ▁pet role um ▁dies el ▁on ▁price . ▁ ▁Many ▁advoc ates ▁suggest ▁that ▁waste ▁veget able ▁oil ▁is ▁the ▁best ▁source ▁of ▁oil ▁to ▁produce ▁b iod ies el , ▁but ▁since ▁the ▁available ▁supply ▁is ▁dr ast ically ▁less ▁than ▁the ▁amount ▁of ▁pet role um - based ▁fuel ▁that ▁is ▁burn ed ▁for ▁transport ation ▁and ▁home ▁he ating