Sustainability and cost comparison of 33 kV overhead transmission lines and underground cables: a life cycle perspective

Abstract

This Manuscript presents an integrated Life Cycle Assessment (LCA) and Life Cycle Costing (LCC) evaluation of five 33 kV distribution designs, including three overhead (OH) lines and two underground (UG) cable systems, under typical Indian operating circumstances. All environmental and economic impacts are constantly normalized per supplied kWh during a 40-year service life, allowing for clear techno-environmental comparisons. The results show that global warming potential (GWP), fossil resource depletion and particulate matter generation are the most significant environmental effect categories. Operational I²R conductor losses are the largest contributor to lifespan impacts when analyzed per delivered electricity. This highlights the relevance of conductor resistance and loading circumstances in infrastructure planning. The comprehensive study demonstrates a clear cost-environment trade-off: underground systems have larger embodied material impacts and capital expenditure, whereas overhead systems have lower initial impacts but are still susceptible to operational loss-related consequences over time. The prevalence of operational losses is exacerbated by Indian grid emission factors and loading practices, emphasizing the significance of region-specific lifecycle normalization. The study establishes a decision-relevant paradigm for assessing 33 kV distribution infrastructure by explicitly connecting conductor design, lifespan environmental performance, and long-term cost efficiency. These insights help utilities and governments optimize medium-voltage infrastructure for ecological and economically effective power delivery.