Energy savings evaluation in public building sector during the 10th–12th FYP periods of China: an extended LMDI model approach

Abstract

Energy savings can be treated as an indicator to reveal the effectiveness of energy efficiency task (EET) in the building sector, especially in the public buildings. However, evaluating the values of energy savings in public buildings (ESPB) was challenged by the missing data sources and inadequate tools in China. To overcome these problems, this study applied an extended Logarithmic Mean Divisia Index model to examine the contributions of different impact factors affecting the public building energy consumption (PBEC) and further evaluated the ESPB values during the 10th–12th Five-Year Plan (FYP) periods in China. Results included three aspects: (1) Absolute values of the contribution of the adjusted PBEC intensity to PBEC denoted the ESPB values in China. (2) Total values of ESPB were 99.9 Mtce during the 10th–12th FYP periods of China. Concretely, the ESPB values during the three FYP periods were as follows: 71.091 Mtce (the 12th FYP period), 19.075 Mtce (the 11th FYP period), and 9.734 Mtce (the 10th FYP period). (3) Effective EET of public buildings was a strong support for the rapidly growing ESPB during the three FYP periods. Furthermore, this study suggested that China should issue the official data on energy consumption in the building sector as quickly as possible, and this action would deeply help the government design targeted plans and policies for the future EET in the building sector.

Appendices

Appendix A

On the basis of the original LMDI decomposition proposed by Ang (2015), the value of PBEC changes (i.e., $\Delta E$) during a period of $\Delta T$ can be indicated as shown below.

$$\Delta E = E|_{T} - E|_{0} = \Delta E_{P} + \Delta E_{U} + \Delta E_{f} + \Delta E_{{L_{\text{s}} }} + \Delta E_{{e_{{{\text{ad}}.}} }}$$

(A-1)

$$\Delta E_{P} = L \times { \ln }\left( {\frac{{P|_{T} }}{{P|_{0} }}} \right)$$

(A-2)

$$\Delta E_{U} = L \times { \ln }\left( {\frac{{U|_{T} }}{{U|_{0} }}} \right)$$

(A-3)

$$\Delta E_{f} = L \times { \ln }\left( {\frac{{f|_{T} }}{{f|_{0} }}} \right) = L \times { \ln }\left( {\frac{{F|_{T} \times P|_{0} \times U|_{0} }}{{F|_{0} \times P|_{T} \times U|_{T} }}} \right)$$

(A-4)

$$\Delta E_{{L_{\text{s}} }} = L \times { \ln }\left( {\frac{{L_{\text{s}} |_{T} }}{{L_{\text{s}} |_{0} }}} \right) = L \times { \ln }\left( {\frac{{\varepsilon \times L_{\text{P}} |_{T} }}{{\varepsilon \times L_{\text{P}} |_{0} }}} \right) = L \times { \ln }\left( {\frac{{L_{\text{P}} |_{T} }}{{L_{\text{P}} |_{0} }}} \right)$$

(A-5)

$$\begin{aligned}\Delta E_{{e_{{{\text{ad}} .}} }} =& L \times { \ln }\left( {\frac{{e_{{{\text{ad}} .}} |_{T} }}{{e_{{{\text{ad}} .}} |_{0} }}} \right) = L \times \left[ {{ \ln }\left( {\frac{{e|_{T} }}{{e|_{0} }}} \right) - { \ln }\left( {\frac{{L_{\text{s}} |_{T} }}{{L_{\text{s}} |_{0} }}} \right)} \right]\\ =& L \times \left[ {{ \ln }\left( {\frac{{e|_{T} }}{{e|_{0} }}} \right) - { \ln }\left( {\frac{{\varepsilon \times L_{\text{P}} |_{T} }}{{\varepsilon \times L_{\text{P}} |_{0} }}} \right)} \right] = L \times \left[ {{ \ln }\left( {\frac{{e|_{T} }}{{e|_{0} }}} \right) - { \ln }\left( {\frac{{L_{\text{P}} |_{T} }}{{L_{\text{P}} |_{0} }}} \right)} \right] \end{aligned}$$

(A-6)

where $L$ represents the $L\left( {E|_{T} ,E|_{0} } \right)$, which indicates the logarithm mean of two positive variables, as demonstrated in Eq. (A–7).

$$L\left( {x,y} \right) = \left\{ { \begin{array}{ll} {\frac{x - y}{{{ \ln }\left( {\frac{x}{y}} \right)}}, \quad x \ne y} \\ {0 , \quad x = y} \\ \end{array} } \right.$$

(A-7)

Following the definition of ESPB, the improved approach to evaluating ESPB values based on Eq. (1) is as follows.

$${\text{ESPB}} = - \left[ { \sum \Delta E_{j} |_{0 \to T} } \right] ,$$

(A-8-1)

where $\Delta E_{j} |_{0 \to T} \in \left\{ { \Delta E_{P} , \Delta E_{U} , \Delta E_{f} , \Delta E_{{L_{s} }} , \Delta E_{{e_{{{\text{ad}}.}} }} } \right\}$, and

$$\Delta E_{j} |_{0 \to T} < 0$$

(A-8-2)

Appendix B

As indicated in Sect. 2.3, the data on PBEC and floor spaces of public buildings in China were collected from Chinese Building Energy Consumption Report (2016) (CABEE 2016), which provided the detailed time-series data on national building energy consumption in China. Furthermore, this report also issued a series of building-related statistical indexes (e.g., floor spaces of different types of civil buildings). The aforementioned data are illustrated in Fig. 7.

Fig. 7

Sources: CABEE (2016)

Trends of civil building energy consumption (${\text{PE}}$, ${\text{RE}}_{1}$, and ${\text{RE}}_{2}$) and floor spaces of civil buildings (${\text{PF}}$, ${\text{RF}}_{1}$, and ${\text{RF}}_{2}$) during the 10th–12th FYP periods in China. Notices: ${\text{PE}}$—Public building energy consumption in China; ${\text{RE}}_{1}$—Residential energy consumption in urban China; ${\text{RE}}_{2}$—Residential energy consumption in rural China; ${\text{PF}}$—Floor spaces of public buildings in China; ${\text{RF}}_{1}$—Floor spaces of residential buildings in urban China; ${\text{RF}}_{2}$—Floor spaces of residential buildings in rural China. URL: http://www.efchina.org/Attachments/Report/report-20170710-1.