Climate-driven resource, cost and resilience assessment of ocean thermal energy conversion systems

Abstract

Ocean thermal energy conversion is a renewable energy technology that utilizes the temperature gradient in the ocean to generate electricity. Climate change affects these plants in two opposing and counter intuitive ways: rising sea temperatures enhance the thermal gradient and increase resource potential, while intensifying extreme weather events undermine plant reliability and intensifying design requirements. Most existing studies assess resource potential using historical climatology and emphasize high-emission futures, overlooking how evolving climate reshapes long-term feasibility, costs, and resilience. This study addresses these gaps employing Coupled Model Intercomparison Project Phase 6 scenarios to evaluate (i) global and small island specific resource potential, (ii) the translation of these resources into levelized cost of electricity for 10 MW offshore and onshore plants under three cost trajectories, and (iii) the structural reinforcements required to withstand stronger hurricanes. A lifetime present cost framework and a benefit cost ratio are applied, incorporating hurricane probabilities and salvage factors. Results indicate that resource viability grows under high emissions, reaching 1.3 × 10⁶ TW globally, while under the green pathway potential remains stable at 0.85 × 10⁶ TW. Levelized costs range from 0.09 to 0.14 USD/kWh in high emissions and 0.10–0.15 USD/kWh in the green pathway. Structural hardening increases costs by 9–36 % for offshore and 5–16 % for onshore designs. Benefit–cost tests suggest resilience upgrades are justified only to Category 2 levels in high-hazard sites, with limited economic value in low-risk regions. Ultimately, exceedance probability and baseline capital costs dominate life-cycle economics, constraining further reinforcement gains.