This paper investigates the energy recovery potential of LNG cold energy using cryogenic binary cycles. The thermoeconomic performance of single-, two- and three-stage Organic Rankine Cycle (ORC) configurations across different working fluids and LNG regasification capacities has been evaluated. The analysis shows that ORC-based LNG cold energy power units achieve specific net power outputs of 45–55 kW/(kgLNG/s) for single-stage, 74–83 kW/(kgLNG/s) for two-stage, and 79–88 kW/(kgLNG/s) for three-stage configurations. The corresponding net energy efficiencies are 6.6–7.5%, 10.1–11.2% and 10.8–12.0%, respectively, while the exergy efficiencies are 15.9–17.6%, 22.9–25.3%, and 24.3–26.8%, respectively. Two-stage systems achieve the lowest costs: a levelized cost of electricity (LCOE) of 80–105 €/MWh and a specific investment cost (SIC) of 6000–8300 €/kW. For most of the evaluated working fluids, the power gain from a third stage does not justify the increase in equipment costs. Among the evaluated working fluids, R32, R41 and R161 achieve the best economic performance, while carbonyl sulfide (COS), R32 and R161 achieve the best thermodynamic performance. The highest net power, 12.5 MW, is achieved with COS, whereas the lowest LCOE (80 €/MWh) and SIC (6000 €/kW) are obtained with R32, all for an LNG regasification capacity of 700,000 Sm3/h.
Bonefačić et al. (Mon,) studied this question.