A total energy efficiency evaluation framework based on embodied energy for the construction industry and the spatio-temporal evolution analysis
Authors: Gao Jingxin , Ren Hong , Ma Xianrui , Cai Weiguang , Shi Qingwei 
Published: May 2019

Purpose
As a typical resource energy-intensive industry, the scale of construction industry has been expanding rapidly owing to the large-scale urbanization and the economic booming in China, which results in a sharp increase in the energy consumption of construction industry. However, it is infeasible to mitigate the energy consumption by reducing the production activities of construction industry. Therefore, improving the energy efficiency of construction industry is essential for energy saving. Construction industry has close relationships with other industries. The production activities have not only consumed a great deal of energy but they have also generated a massive energy consumption from other industries. Previous literature studied the efficiency of energy consumed directly by the construction industry. However, no research has been found focusing on the efficiency of energy consumed directly by the construction industry and indirectly by the related industries. The purpose of this paper is to put forward a total energy efficiency evaluation framework to measure the energy efficiency of construction industry in depth.

Design/methodology/approach
This paper employs the data envelopment analysis (DEA) method and the framework of embodied energy efficiency (EEE) to establish a total energy efficiency evaluation model. Next, the comprehensive analysis of direct energy efficiency (DEE) and EEE in different provinces with various levels of urbanization and various economic levels is conducted.

Findings
The results show that the embodied energy intensity and its regularities differ greatly between provinces. From the comparison of DEE and EEE, the provinces of Zhejiang and Jiangsu remain DEA-effective and Hainan is the only province in which the EEE is higher than DEE in 2002, 2007 and 2012. Besides, the DEE and EEE in the provinces with higher levels of urbanization and high economic levels are not more effective than those in the provinces with relatively lower levels of urbanization and low economic levels.

Originality/value
Previous literature studied the efficiency of energy consumed directly by the construction industry while ignoring the energy consumed indirectly by the related industries. Besides, no research has been found focusing on the regulation of energy efficiency in different provinces with different levels of urbanization and different economic levels. It can be concluded that the increasing levels of urbanization and higher economic levels have not brought development and benefits for improving DEE and EEE. Therefore, under the condition that the self-regulation of construction industry and market fail to facilitate the improvement of DEE and EEE in China, policymakers should develop policies and market incentive mechanism to encourage construction industry for employing new technologies to improve the energy efficiency. Since the EEE can reveal the energy efficiency in depth, the evaluation method of EEE should be paid more attention. Besides the fact that the EEE is lower than the DEE in almost all provinces, except Hainan province, the industrial structure is essential to develop the EEE. Hence, improving the energy structure, increasing the energy efficiency and developing new and renewable energy are the basic energy strategies in China.