经济学人54:天然气是清洁能源吗?

 　　Shale¹ gas extraction

　　页岩天然气开采

　　The need to be seen to be clean

　　天然气是清洁能源吗？

　　Natural-gas production is booming, but its green image is in question

　　天然气生产蒸蒸日上，但它的清洁能源形象却受到质疑

　　May 12th 2011 | AUSTIN, TEXAS AND GOLDEN, COLORADO | from the print edition

　　DRILL rigs tower over the silos on farms in Pennsylvania. Once-empty mesas in western Colorado, where mule² deer and sage³ grouse⁴ ranged freely, now look like a neural⁵ network from a bird’s-eye view, with well-pads connected by dirt roads scattered⁶ across the landscape.

　　宾夕法尼亚的农场，一座座钻塔高耸，俯视着贮粮的圆仓。科罗拉多西部的山顶平地，过去这里曾经一片空旷，只有骡鹿和艾草鸡在上面自由徜徉，现在布满钻井，条条土路联接其间，从高处望过去，就像是一幅密密麻麻的神经网络图。

　　These are the signs of America’s natural-gas boom. Thanks to new drilling technology, and in particular a controversial process called hydraulic⁷ fracturing or “fracking,” the size of the proven reserves is growing. At the end of 2009 the United States had estimated reserves of 283.9 trillion cubic feet (8 trillion cubic metres) of natural gas, up 11% from the year before. In 2010 the country produced 22.6 trillion cubic feet of natural gas, up from 18.9 trillion cubic feet in 2005. The price at the wellhead has dropped from $7.33 per thousand cubic feet to $4.16 during the same period.

　　美国的天然气开采呈现这样一副蒸蒸日上的景象。随着钻井技术，特别是充满争议的水力压裂法（又称破裂法）的广泛采用。已探明的天然气储量不断增加。2009年末，美国估计其天然气储量为283.9万亿立方英尺（合8万亿立方米），比上一年增长了11%。2010年美国开采的天然气为22.6万亿立方英尺。而2005年为18.9万亿立方英尺。同期天然气的出井价也从每立方英尺7.33美元下降到4.16美元。

　　Natural gas is cheap and plentiful⁸. That makes it an appealing alternative to wind and solar power, which are relatively⁹ expensive and erratic¹⁰. And plants powered by gas emit far less carbon dioxide than those powered by dirty coal. Nearly half of America’s electricity is generated by coal, and electricity generation accounts for 40% of America’s carbon-dioxide emissions¹¹. In 2009, the most recent year for which data are available, the country’s greenhouse-gas emissions were at their lowest level since 1995. That was partly due to the bad economy, and partly to the increased use of renewables and natural gas.

　　天然气价格低、储量大，比价格高、稳定性低的风能和太阳能更有优势。如果用天然气发电，它比用煤发电排放的二气化碳量要少很多。美国有近一半的电力来自煤电厂，而美国二氧化碳的40%来自于发电。我们能得到的最新数字是2009年的，这一年温室气体的排放达到了1995年以来的最低点。一部分原因是因为那一段时间经济萧条，另一个原因就是可再生能源以及天然气的使用量增加。

　　But some question whether natural gas is really as green as all that. For one thing, fracking uses a tremendous amount of water, a severely¹² undervalued resource inland. And the process gives off methane¹³, a potent¹⁴ heat-trapper. A study led by Robert Howarth of Cornell University found that greenhouse-gas emissions over the life cycle of natural-gas production could actually be considerably¹⁵ higher than those of coal per unit of energy provided. Greater care about methane venting¹⁶ would, of course, reduce that problem.

　　但有人怀疑天然气是否真得就那么清洁环保。一方面，破裂法需要耗用大量的水，水作为一种陆地上的资源，价值被严重低估。另一方面，这种方法还会释放大量的甲烷，一种极易吸热的气体。康奈尔大学的罗伯特??霍华斯领导的一项研究发现，提供等量的能量，所使用的天然气比所用的碳在整个生命周期里所释放的温室气体大很多。当然，谨慎处置甲烷的排放会减少这种问题。

　　And fracking raises other concerns. In the process, a mix of sand, water and chemicals is pumped deep underground at ferocious¹⁷ pressure. That breaks up shale formations, releasing the gas trapped inside so it can be pumped to the surface. But fracking is almost entirely¹⁸ unregulated, because of a 2005 statutory exemption¹⁹ from the Safe Drinking Water Act. Three members of Congress recently released a report on fracking, saying that oil and gas companies used more than 2,500 fracking products containing 750 chemicals between 2005 and 2009. Some ingredients were benign²⁰, such as citric acid and instant coffee. Others, though, were extremely toxic²¹, such as benzene and lead. Only five states require public disclosure of the chemicals used, and only to limited and varying degrees. That is making landowners, locals and environmentalists edgy²², particularly in big production states like Colorado, Pennsylvania, and Texas, the nation’s largest natural-gas producer, where an enormous reserve—the Barnett Shale—sits under a big city, Fort Worth.

　　同时，破裂法还会带来其他方面的问题。在这个过程中，要用巨大的压力把一种沙、水和很多化学品的混和物压入地下。这会破坏页岩层的构造，致使储藏其间的气体被挤出地表。因为开采天然气在2005年得到《安全饮用水法案》的法定豁免，现在破裂法的使用几乎没有任何的监管。最近有三名国会议员就破裂法发表报告，报告指出，2005—2009年间石油和天然气公司使用的2500多种破裂材料含有750种化学物，有些成分是对人体无害，如柠檬酸、速溶咖啡。但也一些含有巨毒，如苯和铅。只有五个州要求他们向公众披露所使用的化学物，但这种披露程度有限，而且披露要求也不统一。这使得土地所有者、当地居民以及环保分子很是不安，特别在科罗拉多、宾夕法尼亚、得克萨斯等一些天然气生产大州。其中得克萨斯天然气产量最大，沃思堡市巴耐特页岩里储藏着大量的天然气。

　　The chief fear is that the mystery slurry could get into the water supply. In some fracking towns, people have been able to set their tap water on fire. And there have been troubling safety incidents. In late April a big company, Chesapeake Energy, suspended its fracking in Pennsylvania after one of its natural-gas wells blew out and spilled toxic drilling fluid into a nearby creek²³. France has placed a moratorium²⁴ on fracking and is close to a full ban.

　　人们主要担心那种神秘的浆体可能会渗入饮用水源。在一些破裂法开采天然气的城镇，发生了一些安全事故。4月下旬，切萨皮克能源公司在宾州的一个天然气井外溢，致使有毒的液体流入附近小河，该公司的破裂法采气被叫停。法国暂停了该种采气法，不久就会完全禁止。

　　Activists²⁵ and scientists reckon that if the process is safe, the companies should come clean. “If they’ve got nothing to hide, why is the industry so paranoid about disclosing their chemicals?” asks Steve Torbit, executive director of the National Wildlife Federation’s Rocky Mountain region. They may have to. The Environmental Protection Agency is studying the process. In 2009, House Democrats²⁶ proposed legislation that would force the industry to disclose the chemicals it uses in fracking. Several states, including Texas and Colorado, have similar legislation pending²⁷.

　　一些环保人士和科学家认为，如果这个过程是安全的，天然气公司就不应有所隐瞒。“如果无需隐瞒，那为什么他们对于披露使用的化学品的要求那么恐惧呢？”美国落基山地区野生动植物联合会副会长史蒂文??道比特发出这样的疑问。他们可能不得不如此。环保署正在对破裂法进行研究。2009年，众议院中的民主党人士提议立法，强制天然气公司披露他们在使用破裂法中使用的化学物品。有些州，如得克萨斯和科罗拉多，将有类似的法律颁布。

　　In the meantime public concerns are growing. Late last month 200 people packed a Bureau of Land Management hearing in Golden, Colorado. Dave Cesark, an executive at Mesa Energy Partners LLC, tried to reassure²⁸, saying that fracking chemicals constitute “just a drop in the bucket”: only 0.5% of the total fluids, including water, that the company uses to drill natural gas. The crowd did not, strangely enough, find that entirely reassuring²⁹. Some producers will grumble³⁰ that any regulation of fracking is an unwarranted constraint³¹ on their business. But if natural gas is not produced cleanly, it will not prove to be so cheap, either. Full disclosure is a price worth paying.

　　与些同时，公众对这个问题更加关注。上月末，200人齐聚科罗拉多州古尔登土地管理局听证会。Mesa能源合伙公司经理戴夫??赛萨科希望人们打消顾虑，他说，他们在破裂法中使用的化学品只是一篮水中的一滴，仅占包括水在内的液体总量的0.5%。令人感到奇怪的是，他的说法并不能让人完全放心。一些公司抱怨，对破裂法任何的监管措施都是对这种天然气开采方法的无理限制。但如果天然气的生产过程是不清洁的，那么它的成本低廉就无从谈起。对于这种采气法的完全披露也是一项值得支付的成本。

1 shale   

n.页岩，泥板岩

参考例句：

• We can extract oil from shale.我们可以从页岩中提取石油。
• Most of the rock in this mountain is shale.这座山上大部分的岩石都是页岩。

2 mule   

n.骡子，杂种，执拗的人

参考例句：

• A mule is a cross between a mare and a donkey.骡子是母马和公驴的杂交后代。
• He is an old mule.他是个老顽固。

3 sage   

n.圣人，哲人；adj.贤明的，明智的

参考例句：

• I was grateful for the old man's sage advice.我很感激那位老人贤明的忠告。
• The sage is the instructor of a hundred ages.这位哲人是百代之师。

4 grouse   

n.松鸡；v.牢骚，诉苦

参考例句：

• They're shooting grouse up on the moors.他们在荒野射猎松鸡。
• If you don't agree with me,please forget my grouse.如果你的看法不同，请不必介意我的牢骚之言。

5 neural   

adj.神经的，神经系统的

参考例句：

• The neural network can preferably solve the non- linear problem.利用神经网络建模可以较好地解决非线性问题。
• The information transmission in neural system depends on neurotransmitters.信息传递的神经途径有赖于神经递质。

6 scattered   

adj.分散的，稀疏的；散步的；疏疏落落的

参考例句：

• Gathering up his scattered papers,he pushed them into his case.他把散乱的文件收拾起来，塞进文件夹里。

7 hydraulic   

adj.水力的；水压的，液压的；水力学的

参考例句：

• The boat has no fewer than five hydraulic pumps.这艘船配有不少于5个液压泵。
• A group of apprentics were operating the hydraulic press.一群学徒正在开动水压机。

8 plentiful   

adj.富裕的，丰富的

参考例句：

• Their family has a plentiful harvest this year.他们家今年又丰收了。
• Rainfall is plentiful in the area.这个地区雨量充足。

9 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。

10 erratic   

adj.古怪的，反复无常的，不稳定的

参考例句：

• The old man had always been cranky and erratic.那老头儿性情古怪,反复无常。
• The erratic fluctuation of market prices is in consequence of unstable economy.经济波动致使市场物价忽起忽落。

11 emissions   

排放物( emission的名词复数 )； 散发物（尤指气体）

参考例句：

• Most scientists accept that climate change is linked to carbon emissions. 大多数科学家都相信气候变化与排放的含碳气体有关。
• Dangerous emissions radiate from plutonium. 危险的辐射物从钚放散出来。

12 severely   

adv.严格地；严厉地；非常恶劣地

参考例句：

• He was severely criticized and removed from his post.他受到了严厉的批评并且被撤了职。
• He is severely put down for his careless work.他因工作上的粗心大意而受到了严厉的批评。

13 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。

14 potent   

adj.强有力的，有权势的；有效力的

参考例句：

• The medicine had a potent effect on your disease.这药物对你的病疗效很大。
• We must account of his potent influence.我们必须考虑他的强有力的影响。

15 considerably   

adv.极大地；相当大地；在很大程度上

参考例句：

• The economic situation has changed considerably.经济形势已发生了相当大的变化。
• The gap has narrowed considerably.分歧大大缩小了。

16 venting   

消除； 泄去； 排去； 通风

参考例句：

• But, unexpectedly, he started venting his spleen on her. 哪知道，老头子说着说着绕到她身上来。 来自汉英文学 - 骆驼祥子
• So now he's venting his anger on me. 哦，我这才知道原来还是怄我的气。

17 ferocious   

adj.凶猛的，残暴的，极度的，十分强烈的

参考例句：

• The ferocious winds seemed about to tear the ship to pieces.狂风仿佛要把船撕成碎片似的。
• The ferocious panther is chasing a rabbit.那只凶猛的豹子正追赶一只兔子。

18 entirely   

ad.全部地，完整地；完全地，彻底地

参考例句：

• The fire was entirely caused by their neglect of duty. 那场火灾完全是由于他们失职而引起的。
• His life was entirely given up to the educational work. 他的一生统统献给了教育工作。

19 exemption   

n.豁免，免税额，免除

参考例句：

• You may be able to apply for exemption from local taxes.你可能符合资格申请免除地方税。
• These goods are subject to exemption from tax.这些货物可以免税。

20 benign   

adj.善良的，慈祥的；良性的，无危险的

参考例句：

• The benign weather brought North America a bumper crop.温和的气候给北美带来大丰收。
• Martha is a benign old lady.玛莎是个仁慈的老妇人。

21 toxic   

adj.有毒的，因中毒引起的

参考例句：

• The factory had accidentally released a quantity of toxic waste into the sea.这家工厂意外泄漏大量有毒废物到海中。
• There is a risk that toxic chemicals might be blasted into the atmosphere.爆炸后有毒化学物质可能会进入大气层。

22 edgy   

adj.不安的；易怒的

参考例句：

• She's been a bit edgy lately,waiting for the exam results.她正在等待考试结果，所以最近有些焦躁不安。
• He was nervous and edgy, still chain-smoking.他紧张不安，还在一根接一根地抽着烟。

23 creek   

n.小溪，小河，小湾

参考例句：

• He sprang through the creek.他跳过小河。
• People sunbathe in the nude on the rocks above the creek.人们在露出小溪的岩石上裸体晒日光浴。

24 moratorium   

n.(行动、活动的)暂停(期)，延期偿付

参考例句：

• The government has called for a moratorium on weapons testing.政府已要求暂停武器试验。
• We recommended a moratorium on two particular kinds of experiments.我们建议暂禁两种特殊的实验。

25 activists   

n.（政治活动的）积极分子，活动家( activist的名词复数 )

参考例句：

• His research work was attacked by animal rights activists . 他的研究受到了动物权益维护者的抨击。
• Party activists with lower middle class pedigrees are numerous. 党的激进分子中有很多出身于中产阶级下层。 来自《简明英汉词典》

26 democrats   

n.民主主义者，民主人士( democrat的名词复数 )

参考例句：

• The Democrats held a pep rally on Capitol Hill yesterday. 民主党昨天在国会山召开了竞选誓师大会。
• The democrats organize a filibuster in the senate. 民主党党员组织了阻挠议事。 来自《简明英汉词典》

27 pending   

prep.直到，等待…期间；adj.待定的；迫近的

参考例句：

• The lawsuit is still pending in the state court.这案子仍在州法庭等待定夺。
• He knew my examination was pending.他知道我就要考试了。

28 reassure   

v.使放心，使消除疑虑

参考例句：

• This seemed to reassure him and he continued more confidently.这似乎使他放心一点，于是他更有信心地继续说了下去。
• The airline tried to reassure the customers that the planes were safe.航空公司尽力让乘客相信飞机是安全的。

29 reassuring   

a.使人消除恐惧和疑虑的，使人放心的

参考例句：

• He gave her a reassuring pat on the shoulder. 他轻拍了一下她的肩膀让她放心。
• With a reassuring pat on her arm, he left. 他鼓励地拍了拍她的手臂就离开了。

30 grumble   

vi.抱怨；咕哝；n.抱怨，牢骚；咕哝，隆隆声

参考例句：

• I don't want to hear another grumble from you.我不愿再听到你的抱怨。
• He could do nothing but grumble over the situation.他除了埋怨局势之外别无他法。

31 constraint   

n.(on)约束，限制；限制(或约束)性的事物

参考例句：

• The boy felt constraint in her presence.那男孩在她面前感到局促不安。
• The lack of capital is major constraint on activities in the informal sector.资本短缺也是影响非正规部门生产经营的一个重要制约因素。