中国铁路运输33年来的温室气体排放

ESTIMATION OF GREENHOUSE GAS EMISSIONS FROM LOCOMOTIVES IN CHINA RAILWAYS IN RECENT 33 YEARS

铁路是我国重要的交通运输方式,但我国至今尚无铁路运输行业温室气体排放量的报道.文章基于我国铁路部门逐年统计数据,计算了 1975～2007年我国铁路机车的温室气体排放量,分析了我国铁路机车温室气体排放强度及其变化特点.结果表明,我国铁路机车温室气体（CO2和N2O）总排放量逐年降低,由1975年的4278×10^4t CO2当量降至2007年的3844×10^4t CO2当量,总降幅达10%,年均减排14×10^4t CO2当量.其中,CO2年排放量整体呈下降趋势,由1975年的4246×10^4t降至2007年的3645×10^4t,总降幅达14%,年均减排18.8×10^4t; N2O年排放量快速增长,由1975年的1088t增至2007年的6681t,年均增加175t,达16%.由于我国铁路蒸汽机车承担的牵引工作量越来越少,其温室气体年排放量逐年降低,1975～2001年年均减少155×10^4t CO2当量,降幅达3.7%.2002年以后,蒸汽机车基本上从运输领域中被全部淘汰,无温室气体排放.1975～2007年内燃机车和电力机车的排放比重越来越大,其温室气体年排放量逐年上升,内燃机车年均增加54×10^4t CO2当量,电力机车间接排放量年均增长62×10^4t CO2当量.温室气体排放强度呈现明显降低趋势,其值由1975年的8.23kg降至2007年的1.34kg CO2当量/百换算吨公里,降幅达84%,年均降低0.22kg CO2当量/百换算吨公里.其中,内燃机车、电力机车和蒸汽机车的温室气体平均排放强度分别为1.51kg,1.68kg和8.74kg CO2当量/百换算吨公里.大规模淘汰排放强度大的蒸汽机车,同时大量运用排放强度低的内燃机车和电力机车,使得我国铁路机车的温室气体排放量和排放强度不断降低,这为减少我国铁路运输行业的温室气体排放作出了重要贡献.另外,我国铁路机车温室气体排放量占全国化石燃料燃烧的温室气体排放总量的比重很小,因此可以说铁路运输是我国交通运输领域中理想的节能减排运输方式.

Although railway has played a great role in transportation in China,there has been no any study on greenhouse gas emissions from locomotives until now. In this paper, on the basis of the annual production data collected from Chinese Railway Statistic Center, greenhouse gas emissions from locomotives during 1975 -2007 were calculated, and their emission intensities and dynamic characteristics were analyzed. The results show that the total greenhouse gas emissions from steam,diesel and electric locomotives in china decreased from 42.78 million ton CO2 equivalent in 1975 to 38.44 million ton CO2 equivalent in 2007,indicating a mitigation of 0. 14 million ton CO2 equivalent per year（ 10% ）. The emission of CO2 decreased from 42.46 million ton in 1975 to 36.45 million ton in 2007, with a mitigation of 0. 188 million ton per year（14%） ; while the emission of N2O increased from 1088t in 1975 to 6681t in 2007 ,with an increase of 175t per year（16%）. Because fewer and fewer steam locomotives have been put into service, greenhouse gas emissions from steam locomotives decreased during 1975 -2001 at a rate of 1.55 million ton CO2 equivalent per year（3.7% ）. Steam locomotives were out of use after 2002, and no greenhouse gas due to them was emitted. However, more and more diesel and electric locomotives have been put into service, and greenhouse gas emissions from diesel and electric locomotives increased during 1975 - 2007 at a rate of 0.54 million and 0.62 million ton CO2 equivalent per year,respectively. Greenhouse gas emission intensities also decreased from 8.23kg CO2 equivalent per hundred converted ton-km in 1975 to 1.34kg CO2 equivalent per hundred converted ton-km in 2007 at a rate of 0.22kg CO2 equivalent per hundred converted ton-km per year（84%）. The mean greenhouse gas emission intensities of diesel, electric and steam locomotives were 1.51kg CO2, 1.68kg CO2 and 8.74kg CO2 equivalent per hundred converted ton-km,respectively. High-emission-intensity steam locomotives were out of use on a large scale and more and more low-emission-intensity diesel and electric locomotives were put into service, which has led to a low greenhouse gas emission and made an important contribution to the mitigating emissions of greenhouse gas from locomotives in transportation in China. Moreover, greenhouse gas emissions from locomotives accounted for less than 2% of the total emissions from fossil fuel combustion in China. All these show that railway transportation is a perfect way of saving energy and reducing emission in all fields of traffic and transportation. This study can help to present the status of greenhouse gas emission from locomotives, and to provide some information for reducing energy consumption and greenhouse gas emission in Chinese railway transportation.