Assessments on emergy and greenhouse gas
emissions of internal combustion engine
automobiles and electric automobiles in the USA
Ran Jing
1,2,a
, Chen Yuan
2,a
, Hamidreza Rezaei
2
, Jin Qian
3
,
Zhen Zhang
1,*
1
College of Natural Resources and Environment, Joint Institute for Environmental Research & Education, South
China Agricultural University, Guangzhou, 510642, China
2
Department of Civil and Environmental Engineering, University of Maryland at College Park, MD, 20742, USA
3
Research & Development Institute in Shenzhen & School of Natural and Applied Sciences, Northwestern
Polytechnical University, Xi'an, 710072, China
article info
Article history:
Received 17 May 2019
Received in revised form
20 November 2019
Accepted 25 November 2019
Available online 24 December 2019
Keywords:
Emergy
Emergy Index
Electric automobiles
Greenhouse gas emissions
Internal combustion engine
automobiles
abstract
Increasing energy consumption in the transportation sector results in challenging green-
house gas (GHG) emissions and environmental problems. This paper involved integrated
assessments on GHG emissions and emergy of the life cycle for the internal combustion
engine (ICE) and electric automobiles in the USA over the entire assumed fifteen-year
lifetime. The hotspots of GHG emissions as well as emergy indices for the major pro-
cesses of automobile life cycle within the defined system boundaries have been investi-
gated. The potential strategies for reducing GHG emissions and emergy in the life cycle of
both ICE and electric automobiles were further proposed. Based on the current results, the
total GHG emissions from the life cycle of ICE automobiles are 4.48E þ 07 kg CO
2
-e which is
320 times higher than that of the electric automobiles. The hotspot area of the GHG
emissions from ICE and electric automobiles are operation phase and manufacturing
process, respectively. Interesting results were observed that comparable total emergy of
the ICE automobiles and electric automobiles have been calculated which were 1.54E þ 17
and 2.20E þ 17 sej, respectively. Analysis on emergy index evidenced a better environ-
mental sustainability of electric automobiles than ICE automobiles over the life cycle due to
its higher ESI. To the authors’ knowledge, it is the first time to integrate the analysis of GHG
emissions together with emergy in industrial area of automobile engineering. It is expected
that the integration of emergy and GHG emissions analysis may provide a comprehensive
perspective on eco-industrial sustainability of automobile engineering.
© 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sci-
ences. Published by Elsevier B.V.
* Corresponding author.
E-mail addresses: zhangzhen_23102@163.com, zzhangal@scau.edu.cn (Z. Zhang).
a
Both Ran Jing and Chen Yuan contributed equally to this study.
Available online at www.sciencedirect.com
ScienceDirect
www.elsevier.com/locate/jes
journal of environmental sciences 90 (2020) 297 e309
https://doi.org/10.1016/j.jes.2019.11.017
1001-0742/© 2020 The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V.