# A Perfect Decomposition Model for Analyzing Transportation Energy Consumption in China
## 3 Effective Verification and Case Study
### Perfect Decomposition Results Analysis  
Index decomposition models can be divided into period wise and time series according to research objects. Time series decomposition can reflect energy changes trajectory within a certain period, and better explain the change mechanism of transportation energy consumption. Time series decomposition model is used to study transportation energy consumption, and conversion turnover is used in the decomposition process. Based on the perfect decomposition model, we analyze the three factors (transportation turnover volume, transportation structure, transportation energy intensity) affecting transportation energy consumption change and calculate the change of related factors and the contribution rate with the analysis time period from 1985 to 2012. The decomposed results are shown in Table 2. \begin{table}
\begin{tabular}{l c c c c c c c} \hline \hline \multicolumn{1}{c}{**Time**} & \multicolumn{4}{c}{**1985-1995**} & \multicolumn{4}{c}{**1985-2012**} \\ \hline
**Model** & \(\Delta\mathbf{E}\) & \(\Delta\mathbf{E}_{D}\) & \(\Delta\mathbf{E}_{S}\) & \(\Delta\mathbf{E}_{I}\) & \(\Delta\mathbf{E}\) & \(\Delta\mathbf{E}_{D}\) & \(\Delta\mathbf{E}_{S}\) & \(\Delta\mathbf{E}_{I}\) \\ \hline Laspeyres model & 2680.71 & 3069.77 & 538.38 & \(-927.44\) & 19,807.90 & 19,735.56 & 1442.69 & \(-1370.36\) \\ \hline Complete decomposition model & \multirow{2}{*}{2306.64} & \multirow{2}{*}{2906.42} & \multirow{2}{*}{722.16} & \multirow{2}{*}{\(-1321.94\)} & \multirow{2}{*}{23,233.83} & \multirow{2}{*}{20,770.77} & \multirow{2}{*}{6205.35} & \multirow{2}{*}{\(-3742.29\)} \\ \cline{1-1} \cline{5-10} Errors & & & & & & & \\ \hline Errors & — & 5.32\% & 34.14\% & 42.54\% & — & 5.25\% & 330.12\% & 173.09\% \\ \hline proposed perfect decomposition model & \multirow{2}{*}{2306.64} & \multirow{2}{*}{3397.81} & \multirow{2}{*}{716.47} & \multirow{2}{*}{\(-1807.63\)} & \multirow{2}{*}{23,233.83} & \multirow{2}{*}{26,504.38} & \multirow{2}{*}{5190.34} & \multirow{2}{*}{\(-8460.89\)} \\ \hline Errors & — & 10.69\% & 33.08\% & 94.91\% & — & 34.30\% & 259.77\% & 517.42\% \\ \hline \hline \end{tabular}
\end{table} 
Table 1: The calculation results of the three decomposition model. From the decomposed results of the perfect model where transportation turnover volume is the main influence factor in determining the main trend of transportation energy consumption, the contribution is gradually strengthened. The transportation volume makes transportation energy consumption increase by 265.044 Mtce from 1985-2012, according to the perfect decomposition model. Except for a few years, the contribution rate of transportation turnover volume to transportation energy consumption growth is more than 80%. The change in transportation structure, transportation energy, and consumption intensity saves transportation energy consumption by 32.706 (\(51.903-84.609=-32.706\)) Mtce, with an energy saving rate of 10.76%. The average annual energy saving rate is 1.06% from 1985 to 2012. The transportation energy consumption intensity is the main factor of energy saving. From 1985 to 2012, the change in energy intensity saves 84.609 Mtce. Except for 1989-1990, 1995-1996, 1997-1998, 1997-1999, and 2000-2001, 2001-2003, and 2004-2005, most of the other years have energy saving effects. The change in transportation structures reduces the demand for energy in 1988-1989, 1990-1991, 1999-2000, 2002-2003,2003-2004 and 2004-2005, and the energy demand has been increased in most of the other years. Energy demand increased by 51.903 Mtce due to the change of transportation structure from 1985 to 2012, and thus the transportation structure adjustment is the key to saving energy and has great potential to economize. According to the above analysis, the structure adjustment has great energy saving potential. It is necessary to analyze the specific contribution of each transportation mode to energy consumption.