. ▁ ▁The ▁bus , ▁which ▁entered ▁service ▁in ▁south ▁west ▁England ▁in ▁ 2 0 1 4 , ▁is ▁power ed ▁by ▁bi om eth ane . ▁The ▁gas ▁is ▁made ▁from ▁human ▁se w age ▁and ▁food ▁waste ▁which ▁is ▁processed ▁at ▁a ▁plant ▁in ▁Av on mouth ▁run ▁by ▁G EN ec o , ▁a ▁subs idi ary ▁of ▁W esse x ▁Water . ▁It ▁has ▁a ▁Sc ania ▁K 2 7 0 UB ▁ch ass is ▁and ▁an ▁En vi ro 2 0 0 ▁body ▁with ▁ 4 0 ▁seats . ▁A ▁special ▁registration ▁was ▁issued : ▁Y T 1 3 Y UK . ▁ ▁The ▁bus ▁initially ▁served ▁a ▁ ▁Bath ▁Bus ▁Company ▁route ▁between ▁Br istol ▁Airport ▁and ▁Bath . ▁The ▁neighbour ing ▁city ▁of ▁Br istol ▁was ▁European ▁Green ▁Capital ▁in ▁ 2 0 1 5 ▁and , ▁in ▁connection ▁with ▁this , ▁the ▁bus ▁operated ▁in ▁Br istol ▁on ▁the ▁First ▁Br istol ▁number ▁ 2 ▁route . ▁ ▁Similar ▁bus es ▁have ▁operated ▁in ▁Os lo . ▁ ▁When ▁compared ▁with ▁the ▁dies el ▁engines ▁normally ▁used ▁to ▁power ▁bus es , ▁the ▁Bio ▁bus ▁produces ▁ 2 0 – 3 0 % ▁less ▁carbon ▁dio x ide , ▁ 8 0 % ▁fewer ▁nit ro gen ▁ox ides ▁and ▁is ▁low ▁in ▁particul ates . ▁One ▁tank ▁of ▁the ▁gas ▁will ▁power ▁the ▁bus ▁for ▁; ▁however , ▁the ▁bus ▁has ▁to ▁ref uel ▁at ▁the ▁Br istol ▁S ew age ▁Tre at