Evaluation of the environmental effects from hydropower plants using life cycle assessment: A review
Soutnipapha Luangphon, Jia Shen, Xingyu Huang, Jerome Ramirez, Yue Han, Xiuxiu Ruan
Abstract
Hydropower plants (HPPs) are promoted as low-carbon sources that support to reach SDG 7 and SDG 13, yet their true lifecycle emissions remain contested. We reviewed 25 English-language articles covering 65 HPPs via Life Cycle Assessment (LCA): 77 % employed traditional LCA, 19 % used Economic Input-Output LCA (EIO-LCA), and 4 % did not specify their approach. Our analysis reveals that inconsistent system boundaries introduce substantial uncertainty, making cross-study comparisons unreliable. In one case study, the full LCA reported a total greenhouse gas (GHG) emissions estimate of 3723,300 t CO 2 eq, whereas those evaluating only two stages reported emissions of just 2703,300 t CO 2 eq (27.5 % reduction). This discrepancy highlights the significant impact of boundary selection on emission estimates. Additionally, studies also defined the LCA system boundary for HPPs in different ways, which can lead to different approaches in their focus, making studies difficult to compare and benchmark. To address this issue, we propose a standardized five‐phase boundary (preparation, transportation, construction, operation & maintenance, and decommissioning) to ensure comparability and reliability. Embedding such a framework into regulatory impact assessments and carbon‐reporting protocols will improve transparency in permitting, support credible ESG disclosures and green‐bond certification, and guide policy toward genuinely sustainable hydropower development.