????5. 生物柴油

????生物柴油用植物油、動物脂肪或飯店廢棄油脂制成。除了無毒可降解之外，它還能提高傳統柴油的辛烷值，燃燒更清潔。它可以單獨使用，但經常會與80%的傳統柴油混用。政府要求2013年生物柴油產量應達到13億加侖。絕大多數搭載傳統柴油引擎的汽車無需改裝就能使用生物柴油，其中就包括福特汽車公司（Ford）的F-250超能（Super Duty）皮卡。

????5. Biodiesel

????Manufactured from vegetable oil, animal fats, or recycled restaurant grease, biodiesel raises the octane rating of conventional diesel fuel and burns more cleanly, in addition to being non-toxic and biodegradable. Biodiesel can be used in its pure form but is most often found in a blend with 80% conventional diesel fuel. Government regulations required 1.3 billion gallons of biodiesel to be produced in 2013. Biodiesel can be used in most vehicles that have conventional diesel engines without modification, among them Ford's (F,Fortune 500) F-250 Super Duty pickup.