Application of Cryogenic Energy Storage to Liquefied Natural Gas Regasification Power Plant

摘要

A liquefied natural gas (LNG) must be regasified prior to use, and seawater is generally used as heat source. To meet natural gas demand, LNG is continually gasified and its cold energy is highly wasted. This research focuses on the applying LNG cold energy to cryogenic energy storage (CES) system. Moreover, an alternative use of LNG cold energy is proposed with an integration of CES system and LNG regasification power plant; called LNG regasification power plant integrated with cryogenic energy storage (LPCES) system. In the CES unit of proposed LPCES system, entire power consumption and generation are optimized to enhance its storage efficiency. Optimization model is developed mainly focused on compressors and turbines of CES unit. Additionally, a thermodynamic analysis is carried out to explain its cryogenic behavior. Furthermore, an hourly electricity demand and generation in Ontario are applied to evaluate the effect of LPCES system. As a result, a case of applied LPCES system indicated 21.4% minimum reserve margin, which represents electricity reserve over the capacity, compare to 17.7% of the base case. In addition, the result shows a round trip efficiency corresponding to 95.2% for the proposed LPCES system, which is a significantly improved value than efficiencies of developed bulk power management systems. In conclusion, we proposed a novel concept of energy storage system which has a substantial efficiency by LNG cold energy utilization.