▁very ▁similar ▁to ▁those ▁of ▁pet role um ▁dies el , ▁and ▁can ▁replace ▁it ▁in ▁most ▁current ▁uses . ▁ ▁The ▁m eth an ol ▁used ▁in ▁most ▁b iod ies el ▁production ▁processes ▁is ▁made ▁using ▁foss il ▁fuel ▁inputs . ▁However , ▁there ▁are ▁sources ▁of ▁renew able ▁m eth an ol ▁made ▁using ▁carbon ▁dio x ide ▁or ▁bi om ass ▁as ▁feed stock , ▁making ▁their ▁production ▁processes ▁free ▁of ▁foss il ▁fu els . ▁ ▁A ▁by - product ▁of ▁the ▁trans ester ification ▁process ▁is ▁the ▁production ▁of ▁g ly cer ol . ▁For ▁every ▁ 1 ▁t onne ▁of ▁b iod ies el ▁that ▁is ▁manufact ured , ▁ 1 0 0   kg ▁of ▁g ly cer ol ▁are ▁produced . ▁Origin ally , ▁there ▁was ▁a ▁valuable ▁market ▁for ▁the ▁g ly cer ol , ▁which ▁assist ed ▁the ▁econom ics ▁of ▁the ▁process ▁as ▁a ▁whole . ▁However , ▁with ▁the ▁increase ▁in ▁global ▁b iod ies el ▁production , ▁the ▁market ▁price ▁for ▁this ▁cru de ▁g ly cer ol ▁( cont aining ▁ 2 0 % ▁water ▁and ▁catal yst ▁resid ues ) ▁has ▁crash ed . ▁Research ▁is ▁being ▁conducted ▁glob ally ▁to ▁use ▁this ▁g ly cer ol ▁as ▁a ▁chemical ▁building ▁block ▁( see ▁chemical ▁intermediate ▁under ▁Wikipedia ▁article ▁" G ly cer ol "). ▁One ▁initi ative ▁in ▁the ▁UK ▁is ▁The ▁G ly cer ol ▁Challenge . ▁ ▁Usually ▁this ▁cru de ▁g ly cer