Challenges and Metrics for Green Logistics and Sustainable Supply Chains: Application to the Ethiopian Cement Industry

Background: Following industrial energy consumption, freight transportation represents the second-largest source of greenhouse gas emissions nowadays. However, although several metrics for the supply chain’s profitability already exist, indicators for its environmental performance are currently lacking. Methods: Hence, a preliminary review of metrics for green logistics was carried out in order to select a comprehensive indicator for more detailed studies. The effectiveness of the proposed metrics was tested on a real industrial case concerning the Messebo cement factory in Ethiopia to explore potential advances in developing countries, where the availability of renewable energy sources is extremely high but infrastructures for their exploitation are absent. Then, the constrained route optimization problem was solved to investigate the implementation of potential improvements. Results: The outcome of this study shows that delivery route optimization improves transportation environmental performance, on average, by 15%, while the replacement of conventional freight trucks with electric vehicles can abate up to 90% of the overall carbon footprint. In both cases, all constraints were satisfied within the required time window. Conclusions: In conclusion, this work proves the effectiveness of green logistics indicators and represents a first step towards supply chain optimization for carbon-intensive sectors in developing countries.