Abstract
This study analyzes the greenhouse gas (GHG) emissions of an
aluminum ingot manufacturing plant in southern Taiwan, using complete 2023
inventory data to identify emission structures, hotspots, and feasible
reduction strategies. The inventory followed ISO 14064-1:2018 and the Ministry
of the Environment’s classification guidelines, with emissions calculated using
the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report
(AR6) global warming potential values. Hotspot analysis identified five major
emission sources: procurement of primary aluminum, metallic silicon, and scrap
aluminum; combustion of heavy oil in boilers; and purchased electricity.
Improvement strategies were proposed for each hotspot, including raw material
substitution (e.g., recycled aluminum), fuel switching (e.g., natural gas or
biodiesel), energy efficiency measures (e.g., inverters, LED lighting, heat
recovery), renewable energy adoption (e.g., solar PV, T-RECs), and supply chain
carbon disclosure. A multi-criteria assessment framework—considering
controllability, technical maturity, cost, and reduction potential—was used to
prioritize actions. The findings demonstrate the dominance of
supply-chain-driven emissions in the aluminum industry and underscore the need
for supplier cooperation alongside internal efficiency improvements. Although
applied to a single factory, the modular framework provides a replicable model
for small- and medium-sized enterprises (SMEs) to implement carbon management.
Verified by third-party certification (DNV, ISO 14064), the study highlights
the value of continuous inventory refinement and future ISO 14067 certification
to support Taiwan’s net-zero transition.
JEL classification numbers: Q54, Q56, L61, M11.
Keywords: Greenhouse Gas Inventory, Carbon Emission Hotspots,
Aluminum Ingot Manufacturing, Mitigation Strategies, ISO 14064.