Techno-Economic Analysis of Combined Onshore Ocean Thermal Energy Conversion Technology and Seawater Air Conditioning in Small Island Developing States

Aminath Saadha, Keiichi N. Ishihara, Takaya Ogawa, Soumya Basu and Hideyuki Okumura ()
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Aminath Saadha: Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, Japan
Keiichi N. Ishihara: Open Innovation Institute, Kyoto University, Kyoto 606-8501, Japan
Takaya Ogawa: Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, Japan
Soumya Basu: Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, Japan
Hideyuki Okumura: Graduate School of Energy Science, Kyoto University, Kyoto 606-8501, Japan

Sustainability, 2025, vol. 17, issue 10, 1-28

Abstract: Small Island Developing States (SIDS) face energy security challenges due to reliance on imported fossil fuels and limited land for renewable energy. This study evaluates the techno-economic feasibility of integrating Ocean Thermal Energy Conversion (OTEC) and Seawater Air Conditioning (SWAC) systems as a sustainable solution. The research focuses on (1) developing a scalable onshore OTEC-SWAC system and assessing feasibility across 32 SIDS using 20 years of oceanic and atmospheric data, (2) analyzing key system parameters such as pipeline length, pump sizing, and cooling requirements and their effect on capital cost, and (3) developing a scalable cost estimation model for Levelized Cost of Energy (LCOE) predictions. The techno-economic analysis reveals that 30 of the 32 SIDS are technically feasible for OTEC power generation with a temperature gradient of 20 °C. The proposed system is economically feasible in 23 of the SIDS with a calculated average LCOE of 0.16 USD/kWh, which is 67% lower than the diesel LCOE, which is on average 0.46 USD/kWh, making it a cost-competitive alternative. The developed reduced form of the model enables scalable LCOE calculations based on pipeline length and ocean temperature differentials, aiding policymakers in decision-making. By reducing fossil fuel dependency and supporting green tourism, this study provides actionable insights for sustainable energy adoption in SIDS.

Keywords: ocean thermal energy conversion technology; seawater air conditioning; small island developing states; renewable energy (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2025
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