Economic feasibility analysis of LHTES integration with a nuclear power plant

Integrating latent heat thermal energy storage (LHTES) systems into nuclear power plants (NPPs) is a promising approach to improve operational efficiency and ensure load leveling. This study presents a combined techno-economic analysis of LHTES unit integration with the APR1400 reactor. ε-NTU method is used to estimate the design parameters and the performance of the LHTES unit. Capital and operational expenses are estimated for the integrated power generation cycle, considering a life cycle of 25 years. Assuming a 4.83 % annual growth rate in tariffs, annual revenue generated under peak and off-peak tariff scenarios are estimated. Net present value (NPV) analysis is performed for varying phase change material (PCM) costs to determine the profitability thresholds. Based on the NPV results, payback periods are calculated, revealing that profitability can be achieved with peak tariff scenarios at all PCM costs. Internal rate of return (IRR) calculations further demonstrate the conditions under which the system can exceed profitability thresholds. A break-even analysis identifies critical tariff growth rates and PCM cost limits, indicating that the project becomes profitable when the tariff growth rate is above 3.12 % for peak tariffs and 8.18 % for off-peak tariffs. A Monte Carlo (MC) method-based probability analysis shows that the probability of profit is 99.75 % for the peak tariff scenario. Tariff growth and discount rates are the key parameters with high normalized sensitivity indices. Finally, 2D NPV maps demonstrate the combined impact of tariff growth rate and discount rate, providing actionable insights for decision-makers. The economic evaluation reveals that the LHTES system achieves a payback period of 2.71, 3.66, and 5.09 years for PCM costs of 0.6, 2.3, and 4.0 USD/kg, respectively, under peak tariff conditions. The corresponding NPVs by 2050 are 132.69, 68.67, and 4.28 million USD, with internal rates of return (IRR) of 13.28 %, 10.24 %, and 7.20 %. All three cases exhibit benefit-to-cost ratios exceeding unity, confirming profitability. Conversely, under off-peak tariff scenarios, none of the configurations achieve payback within the 25-year project life, and all result in negative NPVs and IRRs, with benefit-to-cost ratios ranging from 0.577 to 0.823. The comprehensive techno-economic analysis of LHTES integration with nuclear power generation highlights the key parameters that drive profitability. Deeper insights are obtained into the economic feasibility of integrating LHTES systems in nuclear power plants.