Up until recently the collection of used cooking oil and its refinement into biodiesel was limited to a few quirky folks that retrofitted their cars and trucks for that purpose. But now, used cooking oil is becoming a hot commodity for prospective biodiesel refiners and distributors looking to and create environmentally friendly businesses. As this biofuel is not primarily produced for energy purposes, but is rather a repurposing of something that might have gone to waste, there are little worries about Energy Return On Energy Invested.