【英语中国】中国少用煤炭方能实现低碳

Any nutritionist will tell you it isn't just the number of calories you consume that's important, but where they come from. The same goes for national economies.

The International Energy Agency caused a stir in July when it said China used more energy than the U.S. last year. But the headline numbers obscured big differences in choice of fuels, with China relying on coal for two-thirds of its energy compared with 22% for the U.S.

Fuel mix has big cost implications. Using the IEA's data for energy sources and average inflation-adjusted prices for different fuels, we can calculate how much must be spent on energy to produce each dollar of gross domestic product. The calculation is a crude one but provides a useful measure of relative performance.

Energy cost intensity has increased everywhere. Between 1994 and 2008, Europe's doubled in real terms to just over three cents per dollar of GDP. North America's rose 88% to 4.4 cents. China's increase was 39%, butits costs are in a different league at 13.5 cents in 2008.

Chinese economic expansion requires more fuel, especially given its gearing toward heavy industry. Energy efficiency is critical and China has delivered on this front: Between 1994 and 2008, calories burned per dollar of GDP fell 41%.

The problem is that the absolute growth in China's energy demand helped push the cost of those calories higher, so its energy cost intensity has risen.

This makes it hard for China to wean itself off coal, which has long been cheaper than natural gas or oil. All else being equal, if China's 2008 energy consumption had mirrored Europe's fuel mix, where coal accounts for just 17%, its cost per dollar of GDP would have been 20 cents instead of 13.5.

China also has a strong incentive to resist carbon pricing, such as an emissions tax. Assuming a global carbon cost of $20 per metric ton, North America's 2008 energy intensity costs would have been 29% higher at 5.7 cents. China's would have soared 66% to over 22 cents.

China's arrival as the world's biggest energy consumer heralds a new era. For Europe and North America, further increases in energy efficiency remain an important way to limit the resulting economic cost. Using more natural gas, in oversupply and cheap relative to oil, is an obvious choice.

China, meanwhile, is on a treadmill, its very success serving to raise energy prices structurally. Becoming more efficient every year is critical -- even more so if it is ever to embrace a low-carbon future.

何一个营养学家都会告诉你，重要的并非消耗的卡路里数量，而是卡路里的来源。国家经济也是同样道理。

国际能源署（International Energy Agency，简称IEA）7月份说中国去年能源消耗量超过美国，引起轩然大波。但是标题数据模糊了两国在燃料选择上的巨大差别，煤炭占中国消耗能源的三分之二，美国则是22%。

燃料结构会大大影响成本。根据IEA不同燃料的来源和通货膨胀调整后的平均价格的数据，我们可以计算出每生产一美元的国内生产总值（GDP）所需能源的成本。计算较粗略，但为相对能耗提供了一个有用的衡量标准。

能源成本强度在世界各个地区都有所增长。1994年至2008年期间，扣除物价因素，欧洲的实际能源成本增加了一倍，每1美元GDP需要消耗超过3美分的能源。北美的能源成本上涨了88%，达到4.4美分。中国的增长幅度仅为39%，但其能源成本与欧美不在同一水平，2008年为13.5美分。

中国经济的扩张需要更多的燃料，特别是考虑到其正在加强重工业的发展。能源效率是关键，中国在这方面取得了一定成效：从1994年到2008年，每1美元GDP消耗的卡路里下降了41%。

问题在于，中国能源需求的绝对增长促使了卡路里消耗成本的上升，因此能源成本强度也随之加大。

这就使得中国“戒掉”煤炭困难重重，煤炭一直以来都比天然气和石油便宜。其他因素不变的情况下，如果中国2008年的能源消耗与欧洲的燃料结构相同，也就是煤炭的份额只占17%，那么每美元的GDP消耗的能源成本将会是20美分，而非13.5美分。

同时，中国有着强烈的动机抵制碳定价，比如碳排放税。假设全球碳价格为每公吨20美元，北美2008年的能源强度成本就会上涨29%，达到5.7美分。中国则将会上涨66%，超过22美分。

中国成为世界最大的能源消耗国，标志着一个新时代的来临。对欧洲和北美来说，进一步提高能源效率仍是抑制能源经济成本的一个重要方法。更多地使用天然气是显而易见的选择，因为天然气比石油供应量大且更便宜。

同时，中国却还处于大量消耗能源的阶段，这一点也正好促使了能源价格的结构性上涨。逐年提高效率至关重要──如果想拥有一个低碳未来这点就更关键了。