页岩气并非“清洁”能源

Op-Ed Contributor
Gangplank to a Warm Future
By ANTHONY R. INGRAFFEA July 31, 2013
观点
页岩气并非“清洁”能源
安东尼·R·因格拉菲 2013年07月31日
 ITHACA, N.Y. — MANY concerned about [要查看本链接请先注册并登录], including President Obama, have embraced hydraulic fracturing for [要查看本链接请先注册并登录]. In his recent climate speech, the president went so far as to lump gas with renewables as “clean energy.”
纽约伊萨卡——许多对[要查看本链接请先注册并登录]表示担忧的人，包括奥巴马总统在内，都接受了水力压裂获取[要查看本链接请先注册并登录]的方法。在他最近关于气候的演讲中，总统甚至把天然气与可再生能源相提并论，称其为“清洁能源”。
As a longtime [要查看本链接请先注册并登录] and gas engineer who helped develop shale fracking techniques for the Energy Department, I can assure you that this gas is not “clean.” Because of leaks of methane, the main component of natural gas, the gas extracted from shale deposits is not a “bridge” to a renewable energy future — it’s a gangplank to more warming and away from clean energy investments.
作为一名工作多年、曾协助为美国能源部开发页岩水力压裂技术的[要查看本链接请先注册并登录]天然气工程师，我可以有把握地说，这种天然气绝非“清洁”。因为天然气的主要成分甲烷的泄漏，从页岩层提取的气体并不是通向可再生能源未来的“桥梁”，它只会加剧全球变暖，并且不利于清洁能源投资。
Methane is a far more powerful greenhouse gas than carbon dioxide, though it doesn’t last nearly as long in the atmosphere. Still, over a 20-year period, one pound of it traps as much heat as at least 72 pounds of carbon dioxide. Its potency declines, but even after a century, it is at least 25 times as powerful as carbon dioxide. When burned, natural gas emits half the carbon dioxide of coal, but methane leakage eviscerates this advantage because of its heat-trapping power.
甲烷是一种远比二氧化碳效力强大的温室气体，尽管它不像后者那样在大气中存留的那样长。不过，在20年时间里，1磅甲烷能够吸收的热量，等同于至少72磅二氧化碳。其效力会随时间而下降，但即便是在一个世纪之后，它的效力也至少是二氧化碳的25倍。在燃烧时，天然气排放的二氧化碳量是煤炭的一半，但是甲烷泄漏的吸热效力抵消了这一优势。

And methane is leaking, though there is significant uncertainty over the rate. But recent measurements by the National Oceanic and Atmospheric Administration at gas and oil fields in California, Colorado and Utah found leakage rates of 2.3 percent to 17 percent of annual production, in the range [要查看本链接请先注册并登录] some years ago. This is the gas that is released into the atmosphere unburned as part of the hydraulic fracturing process, and also from pipelines, compressors and processing units. Those findings raise questions about what is happening elsewhere. The Environmental Protection Agency has issued new rules to reduce these emissions, but the rules don’t take effect until 2015, and apply only to new wells.
甲烷正在泄漏，尽管对于其泄漏率仍存在较大不确定性。但最近美国国家海洋与大气管理局(National Oceanic and Atmospheric Administration)在加利福尼亚州、科罗拉多州和犹他州的气田和油田进行的测量显示，甲烷泄漏率介于年产量的2.3%至17%之间，与我在康奈尔大学([要查看本链接请先注册并登录])的同事和我本人几年前预测的范围相仿。这些是水力压裂过程中被释放到大气中的未燃烧气体，管道、压缩机和加工装置也会有泄漏。这些发现引发了对于其他地方正在发生的情况的质疑。美国国家环境保护局(Environmental Protection Agency)发布了新的规则来减少这些排放，但这些规则得等到2015年才能生效，并且仅适用于新天然气井。
A 2011 study from the National Center for Atmospheric Research concluded that unless leaks can be kept below 2 percent, gas lacks any climate advantage over coal. And a [要查看本链接请先注册并登录] released this May by Climate Central, a group of scientists and journalists studying climate change, concluded that the 50 percent climate advantage of natural gas over coal is unlikely to be achieved over the next three to four decades. Unfortunately, we don’t have that long to address climate change — the next two decades are crucial.
美国国家大气研究中心(National Center for Atmospheric Research)在2011年进行的一项研究得出结论：就气候变化而言，除非泄漏率能够维持在2%以下，否则天然气相对于煤炭没有任何优势。由研究气候变化的科学家和记者组成的气候中心组织(Climate Central)在5月份发表的一份[要查看本链接请先注册并登录]总结道，在未来30到40年里，不太可能使天然气实现高出煤炭50%的气候优势。不幸的是，我们没有这么长时间来应对气候变化，接下来20年至关重要。
To its credit, the president’s plan recognizes that “curbing emissions of methane is critical.” However, the release of unburned gas in the production process is not the only problem. Gas and oil wells that lose their structural integrity also leak methane and other contaminants outside their casings and into the atmosphere and water wells. Multiple [要查看本链接请先注册并登录] show that about 5 percent of all oil and gas wells leak immediately because of integrity issues, with increasing rates of leakage over time. With hundreds of thousands of new wells expected, this problem is neither negligible nor preventable with current technology.
值得肯定的是，总统的计划承认“遏制甲烷排放非常关键”。然而，在开采过程中排放未燃烧气体不是唯一的问题。结构完整性受损的气井和油井，还会把甲烷和其他污染物泄漏到井外，渗入大气和水井。多项[要查看本链接请先注册并登录]显示，有5%的油井和气井因完整性问题而立即发生泄漏，而且随着时间推移，泄漏几率越来越高。鉴于预计有数十万的新井投产，这既不是一个可以忽略的问题，也不是现有技术能够防范的。
Why do so many wells leak this way? Pressures under the earth, temperature changes, ground movement from the drilling of nearby wells and shrinkage crack and damage the thin layer of brittle cement that is supposed to seal the wells. And getting the cement perfect as the drilling goes horizontally into shale is extremely challenging. Once the cement is damaged, repairing it thousands of feet underground is expensive and often unsuccessful. The gas and oil industries have been trying to solve this problem for decades.
为什么有这么多油井和气井发生这种泄漏？原因很多，地层压力、温度的变化、附近钻井引发地层移动，以及收缩，都可能使本应封住油气井的脆弱的薄水泥层产生裂隙，造成损坏。在页岩层进行水平钻井时，保证水泥层的完美是极难的。一旦水泥破损，在几千英尺的地下进行修复将花费不菲，而且常常无法成功。几十年来，油气行业一直在设法解决这个问题。
The scientific community has been waiting for better data from the E.P.A. to assess the extent of the water contamination problem. That is why it is so discouraging that, in the face of industry complaints, the E.P.A. reportedly has closed or backed away from several investigations into the problem. Perhaps a full E.P.A. study of hydraulic fracturing and drinking water, due in 2014, will be more forthcoming. In addition, drafts of an Energy Department study suggest that there are huge problems finding enough water for fracturing future wells. The president should not include this technology in his energy policy until these studies are complete.
科学界一直在等待国家环保局提供更好的数据，以评估水污染问题的严重程度。令人沮丧的是，面对行业的抱怨，环保局据报道停止或退出了数项针对这个问题的调查。也许，环保局定于2014年发表的一项针对水力压裂法和饮用水的全面研究将更加坦率。此外，能源部一项研究的报告草案似乎表明，在为未来的油气井寻找足够水源以进行水力压裂方面，存在巨大的问题。在这些研究完成之前，总统不应把这项技术纳入他的能源政策。
We have renewable wind, water, solar and energy-efficiency technology options now. We can scale these quickly and affordably, creating economic growth, jobs and a truly clean energy future to address climate change. Political will is the missing ingredient. Meaningful carbon reduction is impossible so long as the fossil fuel industry is allowed so much influence over our energy policies and regulatory agencies. Policy makers need to listen to the voices of independent scientists while there is still time.
我们现在拥有的选项有可再生的风能、水力、太阳能和能效技术。我们能以可承受的成本、快速扩大这些能源的利用规模，创造经济增长、就业岗位和一个真正清洁的能源未来，从而应对气候变化。我们欠缺的要素是政治意愿。只要化石燃料产业被允许对我们的能源政策和监管机构施加这么大的影响力，有意义的碳排放削减就是不可能的。在我们还来得及做出改变之前，政策制定者需要聆听独立科学家的呼吁。


[要查看本链接请先注册并登录] is a professor of civil and environmental engineering at Cornell University and the president of [要查看本链接请先注册并登录], a nonprofit group.
 


安东尼·R·因格拉菲([要查看本链接请先注册并登录])是康奈尔大学土木与环境工程学教授，以及非盈利组织“健康能源医生、科学家和工程师”([要查看本链接请先注册并登录])的会长。