Life cycle inventories and life cycle assessment for an electricity grid network: case study of the Jamali grid, Indonesia

Purpose: The electricity and heat sectors are reported to contribute approximately 40% of total CO₂ emissions from the energy sector in Indonesia. Nonetheless, Indonesia is composed of several interconnected electricity-grid networks with different characteristics. This study was conducted to identify the life cycle inventories (LCIs) and perform a life cycle assessment (LCA) to determine the potential environmental impacts of electricity distributed in the Jamali grid network, contributing to 72% of the total electricity produced in Indonesia. Methods: An LCA was conducted with a functional unit of 1 kWh of electricity generated and transmitted in the distribution line in the Jamali grid network in 2018. The system boundary used in this study was cradle-to-gate, covering fuel production and transportation, electricity generation, and electricity distribution. The LCIs were gathered for each power plant’s technology connected to the grid, which includes fuel consumption, fuel-related wastes, infrastructure, land use, water use, and air emissions. The following impact categories were assessed: global warming potential (GWP), acidification potential (AP), eutrophication potential (EP), photochemical oxidation potential (POX), abiotic depletion potential (ADP), abiotic depletion potential–fossil fuels (ADF), and water scarcity footprint (WSF). Methods used to calculate those categories include IPCC GWP 100a, CML-IA (Baseline and Non-baseline), ReCiPe, and AWARE. Results and discussion: LCI analysis showed that the subcritical coal-fired power plants contributed to the highest electricity generation (58.80%), energy consumption (89.39%), and CO₂ production (70.52%) among other technologies connected to the grid. Subsequently, for every 1 kWh of electricity distributed in the grid, the power plants’ operation produced the largest GWP, AP, and POX. Each category produced a total of 1.06 kg CO₂ eq., 5.89 × 10⁻⁰³ kg SO₂ eq, and 4.08 × 10⁻⁰³ kg NMVOC, respectively. The EP and ADF produced were 2.62 × 10⁻⁰³ kg PO₄ eq. and 1.58 × 10¹ MJ, respectively, mainly resulting from coal mining. ADP produced was 2.30 × 10⁻⁰⁵ kg Sb eq. and WSF produced was 3.8 × 10⁻⁰² m³, both majorly contributed by the production of transmission and distribution grid materials. Conclusions: LCA performed to determine the potential environmental impacts from the electricity distributed in the Jamali grid showed that the electricity produced from subcritical coal-fired power plants dominated the electricity mix in 2018. Subsequently, it contributed significantly to multiple impact categories, namely GWP, AP, and POX. Reducing the use of subcritical coal-fired power plants is thus essential to reduce the environmental impacts, which is aligned with the Indonesian government’s plan to reach net-zero emissions by 2060.