这个帖子最初出现on The National Journal's Energy Experts blog.

美国能源部made a big announcementlate last week, green lighting the country’s second liquefied natural gas (LNG) export project. Many argue that natural gas exports will bringeconomicand地缘政治对美国的好处 - 日本和法国公司成为拟议出口站的主要合作伙伴。

Indeed, natural gas can contribute to a lower-emissions trajectory--but onlyif it’s done right。有了有效的政策和标准，天然气可以帮助取代煤炭，同时补充低碳，可再生能源。但是，如果没有这些保护，美国液化天然气出口可能会导致国内温室气体（GHG）排放的增加，并且如下所述，可能会对全球气候变化产生负面影响。必威官网是真的吗

问题成为政府机构和企业是否会采用the necessary steps限制与天然气相关的排放风险，包括通过液化天然气出口。

天然气的环境影响

燃烧天然气释放一半二氧化碳（CO2）作为煤炭，但燃料仍然存在着相当大的环境问题。对于初学者来说，煤炭是relatively low benchmark用于环境表现。没有正确的政策，扩大的天然气可以很容易地取代低碳能源选项，包括可再生能源和能源效率。此外，生产和交付天然气为淡水供应，野生动植物栖息地，空气质量和气候带来风险（请参阅：必威官网是真的吗here，，，，here，，，，andhere).

特别关注的是“逃亡的甲烷排放，”which escape into the air from various points throughout natural gas systems, reducing the net benefit of switching to gas from coal or oil-based fuels. Methane is a potent greenhouse gas—at least 25 times stronger than CO2.Reducing emissionsof this gas could help toslow the rateof climate change.

RecentWRI分析发现尽管有许多已知的策略和技术to reduce fugitive methane，，，，much more could be done cost-effectively. In fact, through the broader use of available technologies and best practices, fugitive methane from natural gas systems could be cut to less than 50 percent of current levels.

液化天然气出口：更高的国内排放，可疑的气候利益必威官网是真的吗

While increased domestic natural gas production has been credited with recent reductions in U.S. CO2 emissions, exporting natural gas would likely have the opposite effect. Three issues come into play:

  1. 出口液化天然气需要液化，运输然后再进行重新化，这是一个高能量密集型的过程。The DOE’s National Energy Technology Laboratory估计从这个过程中的排放将超过双打国内天然气生产的“上游”生命周期排放量 - 燃料燃烧之前发生的那些排放。当在“下游”二氧化碳排放中（即燃料燃烧产生的排放）中，出口LNG比在国内生产和消耗的天然气高出约15％。此外，这些额外排放中的60％以上将发生在国内液化终端。

  2. The Energy Information Administration (EIA)项目that exporting LNG would increase U.S. natural gas production, mostly from shale wells.An inevitable consequence would be greater upstream air emissions from natural gas infrastructure, including fugitive methane and CO2 emissions. Expanded natural gas production comes with all of the inherent environmental risks listed above, particularly under current policies, which could be更具保护性of public health and the environment.

  3. The EIA最近结束了that any amount of LNG exports would put upward pressure on U.S. natural gas prices domestically.This would make natural gas less competitive in U.S. electricity markets, likely causing a shift toward greater coal-fired power generation. Unlesspower plant emissions standardsare in place to avoid this outcome, the result would be higher CO2 emissions from the U.S. power sector.

Plus, U.S. LNG exports may not actually curb global climate change, as supporters contend. Certainly, greater international supplies of natural gas would help reduce market prices for this fuel and, therefore, reduce reliance on higher-carbon fuels, such as coal or fuel-oil. However,造型by the International Energy Agency has found that an expanded international natural gas market – which would result from U.S. LNG exports, plus increased natural gas production elsewhere – would only reduce global energy-related CO2 emissions by 0.5 percent below business-as-usual by 2035. That’sless than 10 percent在同一时期内由全球天然气和石油系统逃亡的甲烷引起的预计温室气体排放。换句话说，没有新政策和技术干预措施，，，，any climate benefits from increased natural gas use internationally could be dwarfed by accelerated warming caused by fugitive methane emissions. These projections underscore the urgent need to minimize fugitive methane emissions在美国and internationally (seehereandhere).

An Urgent Need for Climate Policy

的确，天然气比煤炭少碳密集型。天然气发电通常比燃煤或油燃料更有效。天然气发生器是间歇性风能和太阳能的绝佳补充。然而，recent historyandenergy sector建模研究告诉我们天然气不会用作低碳桥燃料在其自己的。为了稳定气候，我们需要政策来减少未必威官网是真的吗来几十年中从天然气的温室气体排放到当前水平的一小部分。这可能是通过刺激现有技术来遏制上游排放的政策来部分完成的，还可以通过部署碳捕获和存储（CCS）来遏制上游排放量（CCS）来从天然气燃烧的电源中排放二氧化碳排放。在开放扩大的美国天然气生产和液化天然气出口的大门之前，我们需要充分了解associated risks- 并制定强大的政策来减轻它们。

在接下来的几个月中，奥巴马政府has the opportunityto ensure the country is on a low-emissions trajectory. Reining in methane emissions from natural gas is a key piece of that puzzle. As WRI’srecent report found，，，，the administration can also place new standards on power plants, reduce hydroflourocarbons from refrigerants, and help increase energy efficiency. Together, these steps will help the administration reach its emissions goal and move the United States toward a safer, lower-carbon future.