Economic Aspects and Sustainability of Ethanol Production—A Systematic Literature Review

Tamás Mizik

doi:10.3390/en14196137

Abstract

Meeting the increasing global energy demand in a sustainable way is a major challenge for humanity. One of the solutions in the transportation sector is ethanol, which is currently the only economically viable direct fuel substitute. In addition to the first-generation technology, which provides the vast majority of production, better results can be continuously realized by using advanced technologies. This study aims to investigate the economic aspects and sustainability issues of ethanol production with a systematic literature review. During the selection process, 64 studies from a total of 16,141 identified articles were analyzed in-depth. There is a consensus that first-generation production methods cannot result in a long-term solution. However, advanced technologies are currently immature, and ethanol production is more expensive with them. The use of wastes/residues and coproducts can improve both the economic outlook and sustainability of the advanced technologies. Overall, the newer generations of technological advancements are constantly improving the environmental performance, whereas the economic performance is deteriorating. Considering low oil prices (0.36 USD/L), none of the ethanol production methods can be competitive on a purely cost basis. This increases the importance of coproducts (further processing and more valuable coproducts). Regarding sustainability, a complex analysis is essential, which must cover at least the environmental, social, and economic aspects. At the methodology level, a complex life cycle analysis seems to be the best tool, as it can take into account these relevant aspects (environmental, economic, and social).

Highlights

The Earth’s fossil energy resources are limited, because the extent of their exploitation significantly exceeds their reproduction
Due to the better separation of environmental impacts and possible data problems, Ekvall [1] suggested attributional (ALCA) and consequential (CLCA) life cycle assessments (Appendix A contains the main abbreviations used in the text)
Combined production is characterized by the simultaneous production of 1G and 2G ethanol in the same biorefinery; during lignocellulosic production, normally, nonedible feedstocks are used; algae ethanol production is based on micro- and macroalgae

Summary

Introduction

The Earth’s fossil energy resources are limited, because the extent of their exploitation significantly exceeds their reproduction. The so-called first-generation (1G) biofuels are suitable for the short term Their sustainable use is based on the renewable nature of the raw materials used for production. They produce much less greenhouse gases (GHGs) when compared to crude oil. During their combustion, only the amount of CO2 that the plant has captured from the air during its life cycle will be released. Only the amount of CO2 that the plant has captured from the air during its life cycle will be released These CO2 savings can be significant even with 1G biofuels, but it can be even greater for further generations due mainly to the potentially negative CO2 balance of the production process. The ALCA makes it possible to estimate the product-level global environmental burdens, while the CLCA estimates the impacts of the production and use of the product on environmental loads

Objectives

Findings

Discussion

Conclusion