Researchers from the University of Nevada, Reno, have discovered that coffee can be turned into an alternative fuel other than caffeine: biodiesel. And you can have your coffee and drink it too. No need to use the fresh stuff, old grounds are more than up to the task, according to material scientist Mano Misra and his colleagues.

Even after being subjected to the rigors of brewing, roughly 15 percent of the weight of dried coffee grounds is oil, which, much like palm and soybean oil, can be converted into biodiesel. The coffee has the added benefit of not being a food source, like palm oil and soybeans.

Nevertheless, more than 16 billion pounds of coffee are produced globally every year, according to the U.S. Department of Agriculture. Misra estimates that the grounds from that haul could be used to make as much as 340 million gallons of biodiesel. For their part, the researchers turned grounds donated by Starbucks into biodiesel that had the added advantage of smelling like a fresh cup o' Joe.

The researchers note that coffee's high proportion of antioxidants, such as chlorogenic acid, acts as a natural preservative for the resulting biodiesel, preventing it from going bad like other forms of biofuel and even petroleum diesel can. The researchers hope to set up a pilot plant to convert grounds into biodiesel next year and estimate that, for its part, Starbucks in the U.S. alone could turn a profit of $8 million a year from the process, assuming that both the biodiesel and leftovers of the process can be sold.

To chill this simmering cup a bit: the U.S. Department of Energy says that the U.S alone burns 40 billion gallons of diesel a year, meaning that converting all the grounds in the world wouldn't even contribute 1 percent of U.S. diesel consumption. Still, it's an idea that could perk you up.

来自位于里诺的内华达大学的研究者们发现，咖啡可以被转变为替代燃料：生物柴油，而不是咖啡因。当然你仍然可以得到咖啡喝。根据材料科学家Mano Misra和他的同事们的研究，作燃料用的咖啡不需要使用新鲜的咖啡，剩余的咖啡残渣就足够用了。

咖啡即使泡过，剩余咖啡残渣中占重量大约15% 的部分仍然是油，这些油就像棕榈油和黄豆油一样，可以被转化成生物柴油。棕榈油和大豆油是人们的食物来源，而用咖啡作燃料的另外一个好处就是它不是食品来源。
 
根据美国农业部的数据，全球每年产出超过160亿磅的咖啡。Misra估算，用这些大量咖啡的剩余残渣可以制造出多达3.4亿加仑的生物柴油。研究者们把星巴克赠给他们的咖啡残渣转变成生物柴油，这些柴油闻起来还有一种新鲜咖啡的味道呢！

研究者们注意到咖啡中高含量的抗氧化剂，比如绿原酸，对所生产的生物柴油能起到天然防腐剂的作用，这样就可以防止这种生物柴油变味，而其它形式的生物柴油甚至石油柴油都能变味。研究者们希望明年建立一个把咖啡残渣转化成生物柴油的实验工厂。他们估计，假设由此生产的生物柴油以及该加工过程中获得的其它东西能被卖出的话，那么仅仅在美国的星巴克一年就可以从中获得800万美元的利润。

前景似乎不错，不过还是要泼点冷水。美国能源部称，仅美国一个国家一年就要烧掉400亿加仑的柴油，这意味着即使把全球的咖啡残渣都转化成生物柴油，这还不能满足美国柴油消耗的1%。但是，把咖啡残渣变废为宝的想法可能还是能使你为之一振吧！

Vocabulary:

Alternative: 选择
Caffeine: 咖啡因
Biodiesel: 生物柴油
Rigor: 严格；精确
Brew: 酿造
Palm: 棕榈
Convert: 转化
A fresh cup o' Joe：（口语）一杯新鲜咖啡
Antioxidant: 抗氧化剂
Chlorogenic acid: 绿原酸
Preservative: 防腐剂
Chill: 冷却
Simmer: 小火慢煮；心中充满
Perk up: 活跃起来；振作精神