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　　At the 1900 World's Fair in Paris, Rudolf Diesel¹ exhibited an engine that could run on oil from vegetables and plants. But Diesel's design was eclipsed by automobile³ engines that ran on petroleum-based fuel. Today, though, with concerns about the environment and the supply of oil, diesel engines – and the sustainable options for running them – are getting a second look. Auto² industry analysts⁴ expect sales of diesel-powered cars in the United States to triple in the next decade, and many of those drivers will be looking for plant-based fuel, "bio-diesel," to put in their tanks.
在1900巴黎世界博览会上，鲁道夫.狄塞尔展示了用菜油和植物油驱动的柴油机，但是，狄塞尔的柴油机却被以石油为基础的燃油驱动的汽车发动机所淘汰。今天，随着对环境和石油供应的担忧，柴油机及其他能驱动柴油机的可持续性选择再次引起人们的注意。汽车工业分析人士预测，在美国，柴油驱动汽车的生产在今后十年里将会增加三倍，而且驾驶这种汽车的人也会用植物燃油，或者叫生物燃油来装满他们的油箱。
Biodiesel is made from processed vegetable or plant oil, and can be used in diesel engines on its own, or blended with petroleum-based fuel. Here in Berkeley, California, the pumps at Biofuel Oasis⁵ dispense⁶ diesel made from used cooking oil.
生物柴油是以菜油或是植物油加工而成的燃油。可以单独用于柴油机，也可以和以石油为基础的燃油混合使用。在加利福尼亚州的伯克利有一个加油站，名字叫生物燃油绿洲。
The fueling station is a cooperative, owned by five women. Margaret Farrow says Oasis was opened to offer a sustainable option to the petroleum-derived diesel offered by big oil companies. "It's a clean-burning fuel. It's more efficient than gasoline. It's biodegradable, non-toxic, non-flammable," she says, adding that it's good for the environment, too. "In terms of greenhouse gasses, if you use biodiesel, there's no net increase of carbon dioxide going into the environment."
那里的油是从已经用过的食用油制成的。这个加油站由五个妇女共同经营，是一个合作项目。玛格丽特.法罗说，他们开设绿洲加油站的目的就是让人们在使用大型石油公司出售的那种从石油提炼的柴油外，还能够有一种可持续的选择。法罗说：“这是一种清洁的燃油，比汽油更有效。这是一种生物可降解的，无毒、非易燃性的燃油。另外，从温室气体排放来说，如果使用生物柴油，不会增加空气中的二氧化碳含量。”
Since Biofuel Oasis opened in 2003, about 2,500 customers have pulled in to fill up. For Sandra Lupien, coming here is an ethical⁷ choice. "An important point for me about using biodiesel is to make sure that we're using biodiesel that is made from recycled vegetable oil, oil picked up from restaurants that's just going to be thrown away anyway, instead of using oil processed from new crops."
自从生物绿洲加油站2003年开业以来，大约有2500名顾客到这个加油站来加油。桑德拉.卢皮恩就是其中的一位。卢皮恩说：“使用生物柴油对我来说很重要的是，能够保证我们所用的生物柴油是来自回收的菜油，而不是由新的庄稼加工提炼的油。餐馆里用过的油反正是要扔掉的。”
There are two types of biodiesel fuel: Fresh or "virgin⁸" biodiesel is made from crops such as soybeans. Then there's the biodiesel fuel made from recycled vegetable oil which only a few fueling stations besides the Oasis sell – currently at $1.10 ten per liter, about five cents less than regular diesel fuel and ten cents more than gasoline in California.
目前有两种生物柴油，一种是原始的柴油，也就是从大豆等庄稼中加工提炼的。另一种就是从回收的菜油里提炼的。第二种油除了绿洲加油站以外只有少数几个加油站出售这样的燃油。目前这种燃油的价格为每升一美元。在加州，这个价格比普通柴油高出五美分，比汽油高出十多美分。
Even though diesel is more expensive than gasoline, liter for liter, it's cheaper to run a diesel car. Diesel engines are designed to be more efficient than gasoline engines, so they provide higher fuel efficiency. But it can be more of a challenge to find a place to fill up a car that runs on diesel. Not all service stations carry diesel, and pumps serving up biodiesel are rare indeed. Nationally, there are only about 1600 biodiesel fueling stations, with most clustered in the grain-growing states of the Midwest, and a few along the coasts.
尽管按升计算，柴油的价格高出汽油，但是，驾驶柴油驱动的汽车却更便宜。柴油机的设计要比汽油发动机更有效，因此燃油效率更高。但是要找到一个可以给柴油驱动的汽车加油的地方可能会大费周折。不是所有的加油站都提供柴油，能供应生物柴油的加油站就更为稀少。事实上，美国只有1600个生物柴油加油站，而且大多数集中在中西部以及东西海岸。
The biodiesel sold at Oasis comes from Yokayo Biofuels, the only commercial-scale plant in northern California that manufactures the fuel from used vegetable oil. Kumar Plocher founded the company in 2001, and it now produces about 3700 liters of biodiesel fuel every day.
绿洲加油站出售的生物柴油来自加州北部利用回收菜油生产燃油的唯一一家商业炼油厂。布洛克是位于加利福尼亚州尤凯亚的一家生物燃料公司的总裁兼创办人。尤凯亚市在旧金山以北大约两个小时车程的地方。该公司2001年开始营业，目前每天生产大约3千7百升生物柴油。
Plocher has a fleet of biodiesel-powered trucks that collects used cooking oil from about 700 restaurants across northern California. Once at the processing plant, the oil goes through a series of screeners, high-speed shakers, hot tanks and washes to remove food residue⁹ and water. The separated food products are composted, and the filtered oil begins its transformation¹⁰. Treated with methanol and potassium hydroxide, also known as lye, the vegetable oil molecules¹¹ break down.
布洛克拥有一个使用生物柴油的卡车队，这些卡车从北加州大约7百家饭店那里搜集用过的食用油。这些油被运到处理工厂后就会经过一个加工程序，其中包括过滤，快速搅拌、高温和去除食物残渣和水分清洗过程。分离出来的食品被合成肥料。经过过滤的油便开始它的转换过程。植物油分子经过甲醇和钾的氢氧化物、也被称作灰汁的处理后就被分解。
Plocher explains that this step is the most dangerous aspect of the operation. "People ask if biodiesel is a dangerous fuel. Once you've actually made it and purified it, it's completely non-toxic and non-hazardous."
布洛克说：“这是我们操作过程中最危险的一步。人们问，生物柴油是不是一种危险的燃油。实际上，这种油一旦经过生产和纯化，就完全没有毒性，也没有危险。”
But Plocher admits there is still a great deal of negativity surrounding biodiesel fuels. "Right now the [public sentiment] about biofuels in general and, certainly, biodiesel as well as ethanol, is very negative." He points to news reports and studies focused on the diversion of food crops for fuel and the environmental costs of clearing land for biofuel crops. And he counters, "It's very easy to show that this kind of biodiesel that we're making has serious net positives. But if you're going to take an acre of someone's food garden and replant it to make energy, there's problems with that."
但是布洛克承认，对生物柴油还是有许多负面的看法。他说：“有很多人质疑生物柴油是否给地球造成的消极作用大于积极作用。很容易证明我们制造的这种生物柴油所产生的积极作用比消极作用要大得多。但是，如果你为了生产能源，而拿别人的一公顷粮食作物土地来换种产油作物的话，那就有问题了。”
Plocher says because of the huge amount of land required to grow biodiesel crops – often land where food crops had been grown – some biodiesel producers are importing palm oil from the tropics to make their fuel. But that's not a perfect solution, either. Not only are there increased transportation costs, but the growing demand for palm oil has caused the destruction of rainforests in Malaysia, Indonesia and other tropical countries.
Kumar Plocher serves on the National Biodiesel Board's Sustainability Task Force, working to develop a road map for the industry. With an eye on its impact on the environment and the global food supply, he says, the search is on for sustainable, super biodiesel crops, "stuff that doesn't compete with food, that you can get a whole lot of energy per hectare."
布洛克是美国生物柴油委员会的可持续性发展行动小组的成员，他为这一行业的发展制定规划。他说，他在关注生物柴油对环境和全球食品供应造成的影响的同时，正在寻找可持续性发展的超级生物柴油作物。
He says soybeans provide only a tiny amount of oil, and mustard seed and sunflowers are somewhat more productive. "But there are trees that actually grow well in California and across a lot of the United States called Chinese Tallow trees. They can give you upwards¹² of 4,730 liters a hectare. We're looking into those. Difficult to harvest but they can be one of the real feedstocks of the future." Algae¹³ is another possibility, he says. "We can get [tens of thousands of liters per hectare] with algae ponds. So there are all kinds of more sustainable choices for the future."
Whatever it's made from, industry experts expect biodiesel to be an important part of the energy supply of the future.
然而不论用什么材料制造生物柴油，工业领域的专家们期望生物柴油能够成为未来能源供应的重要组成部分。