With global warming leading to abnormal weather phenomena and increasing carbon emissions, countries are implementing carbon emission reduction policies. Europe’s Carbon Border Adjustment Mechanism (CBAM) aims to promote environmentally responsible practices while maintaining industrial competitiveness. To avoid potential tariffs in the European market, Korea must vigorously pursue carbon emission reduction. Emphasizing renewable energy adoption is crucial for achieving eco-friendly and sustainable energy production. This study conducted an economic feasibility assessment for constructing small hydroelectric power plants using discharged energy from Goseong Green Power Plant. By evaluating economic viability, decision-makers could assess potential benefits and costs to support effective planning and implementation. Findings of this study could encourage investments in renewable energy projects, fostering a greener and more sustainable energy landscape for the future.