VOA标准英语2010年-Getting Mileage Out of Manure

Dairy farmer, researchers look for ways to power cars with bio-gas from cattle

Tom Banse | Bellingham, Washington 23 February 2010

Dairy owner Darryl Vander Haak turns cow manure¹ into 'bio-gas' which burns like natural gas in a small electric power plant right on his farm.

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Western Washington University's Vehicle Research Institute

Five years ago, dairy farmer Darryl Vander Haak flipped² the switch on the first electric generator³ in Washington State powered by manure. The facility is officially known as a methane⁴ digester.

Manure from about 1,000 cows goes in one end and then, controlled decomposition⁵ yields methane gas at the other.

The raw material for the digester comes from livestock⁶ waste that might otherwise end up in a smelly manure lagoon⁷ on the farm. This so-called 'bio-gas' is burned like natural gas in a small electric power plant right on Vander Haak's farm. The dairyman sells his excess power to the local electric utility.

Methane digesters are increasing in number, especially in Europe. But there's an important difference between Europe and America: electricity in the U.S. is relatively⁸ cheap. Dairyman Vander Haak says his energy sales have not been profitable. "The Northwest has too much [cheap] hydropower to compete with," he points out, adding that he's been looking for alternative markets. "It would be easier to compete with the gas companies, I guess."

Cow power to horsepower

That's why Vander Haak was open-minded when the Vehicle Research Institute at Western Washington University, just down the road from his dairy, called with an offer to truck away some of his methane.

One researcher calculates that cows from two large dairies could fuel all public buses in a medium-sized American city.

Institute director Eric Leonhardt says he's had his eye on the dairy herd⁹ as a source of transportation fuel for a long time. He calls it "cow power to horsepower."

Leonhardt says the challenge is to cost-effectively remove impurities¹⁰ from the manure-derived methane. "When the gas comes off the digester, it has not only methane in it - 60 percent -- it also has carbon dioxide -- 40 percent, roughly. And it has a trace of hydrogen sulfide," says Leonhardt. Those impurities rapidly corrode¹¹ engine parts.

Powering vehicles with clean natural gas is not new. Nor is generating fuel from renewable sources. But cars and trucks that run on methane are still a novelty in the U.S.

However, since last year, biogas has gotten renewed attention from the Obama Administration as part of a larger push to promote domestic renewable energy.

The Viking 32, built by students and faculty¹² at Western Washington University, runs on biofuel.

The economics of methane-powered cars

The U.S. Department of Energy gave the Vehicle Research Institute a $500,000 grant to improve the biogas refining process and then demonstrate whether the fuel can be cost-competitive in cars. Leonhardt says a lot depends on the price of traditional fossil fuel.

It would have to climb higher to give consumers a financial incentive¹³ to switch. At present, the average price of gasoline in the United States is well below Leonhardt's barely-competitive threshold of about 75-cents per liter.

This spring, the Vehicle Research Institute plans to retrofit a donated shuttle bus to run on methane. It will take a few months of road testing to confirm Leonhardt's cost estimates. The researcher has already calculated that the cows from just two large dairies could fuel all the public buses in a medium-sized American city.

 

1 manure   

n.粪，肥，肥粒；vt.施肥

参考例句：

• The farmers were distributing manure over the field.农民们正在田间施肥。
• The farmers used manure to keep up the fertility of their land.农夫们用粪保持其土质的肥沃。

2 flipped   

轻弹( flip的过去式和过去分词 )； 按（开关）； 快速翻转； 急挥

参考例句：

• The plane flipped and crashed. 飞机猛地翻转，撞毁了。
• The carter flipped at the horse with his whip. 赶大车的人扬鞭朝着马轻轻地抽打。

3 generator   

n.发电机，发生器

参考例句：

• All the while the giant generator poured out its power.巨大的发电机一刻不停地发出电力。
• This is an alternating current generator.这是一台交流发电机。

4 methane   

n.甲烷，沼气

参考例句：

• The blast was caused by pockets of methane gas that ignited.爆炸是由数袋甲烷气体着火引起的。
• Methane may have extraterrestrial significance.甲烷具有星际意义。

5 decomposition   

n. 分解, 腐烂, 崩溃

参考例句：

• It is said that the magnetite was formed by a chemical process called thermal decomposition. 据说这枚陨星是在热分解的化学过程中形成的。
• The dehydration process leads to fairly extensive decomposition of the product. 脱水过程会导致产物相当程度的分解。

6 livestock   

n.家畜，牲畜

参考例句：

• Both men and livestock are flourishing.人畜两旺。
• The heavy rains and flooding killed scores of livestock.暴雨和大水淹死了许多牲口。

7 lagoon   

n.泻湖，咸水湖

参考例句：

• The lagoon was pullulated with tropical fish.那个咸水湖聚满了热带鱼。
• This area isolates a restricted lagoon environment.将这一地区隔离起来使形成一个封闭的泻湖环境。

8 relatively   

adv.比较...地，相对地

参考例句：

• The rabbit is a relatively recent introduction in Australia.兔子是相对较新引入澳大利亚的物种。
• The operation was relatively painless.手术相对来说不痛。

9 herd   

n.兽群，牧群；vt.使集中，把…赶在一起

参考例句：

• She drove the herd of cattle through the wilderness.她赶着牛群穿过荒野。
• He had no opinions of his own but simply follow the herd.他从无主见，只是人云亦云。

10 impurities   

不纯( impurity的名词复数 )； 不洁； 淫秽； 杂质

参考例句：

• A filter will remove most impurities found in water. 过滤器会滤掉水中的大部分杂质。
• Oil is refined to remove naturally occurring impurities. 油经过提炼去除天然存在的杂质。

11 corrode   

v.使腐蚀，侵蚀，破害；v.腐蚀，被侵蚀

参考例句：

• The tools will corrode with rust if never used.这些工具如长期不用会长铁锈而损坏。
• It will pollute people's aesthetic taste and corrode social spirit.它污染人们的审美趣味，腐蚀社会精神。

12 faculty   

n.才能；学院，系；(学院或系的)全体教学人员

参考例句：

• He has a great faculty for learning foreign languages.他有学习外语的天赋。
• He has the faculty of saying the right thing at the right time.他有在恰当的时候说恰当的话的才智。

13 incentive   

n.刺激；动力；鼓励；诱因；动机

参考例句：

• Money is still a major incentive in most occupations.在许多职业中，钱仍是主要的鼓励因素。
• He hasn't much incentive to work hard.他没有努力工作的动机。