Wenyi Liu

Analysis and Optimization of a Compressed Air Energy Storage—Combined Cycle System

Compressed air energy storage (CAES) is a commercial, utility-scale technology that provides long-duration energy storage with fast ramp rates and good part-load operation. It is a promising storage technology for balancing the large-scale penetration of renewable energies, such as wind and solar power, into electric grids. This study proposes a CAES-CC system, which is based on a conventional CAES combined with a steam turbine cycle by waste heat boiler. Simulation and thermodynamic analysis are carried out on the proposed CAES-CC system. The electricity and heating rates of the proposed CAES-CC system are lower than those of the conventional CAES by 0.127 kWh/kWh and 0.338 kWh/kWh, respectively, because the CAES-CC system recycles high-temperature turbine-exhausting air. The overall efficiency of the CAES-CC system is improved by approximately 10% compared with that of the conventional CAES. In the CAES-CC system, compressing intercooler heat can keep the steam turbine on hot standby, thus improving the flexibility of CAES-CC. This study brought about a new method for improving the efficiency of CAES and provided new thoughts for integrating CAES with other electricity-generating modes.

Performance Analysis of a Coal-Fired External Combustion Compressed Air Energy Storage System

Compressed air energy storage (CAES) is one of the large-scale energy storage technologies utilized to provide effective power peak load shaving. In this paper, a coal-fired external combustion CAES, which only uses coal as fuel, is proposed. Unlike the traditional CAES, the combustion chamber is substituted with an external combustion heater in which high-pressure air is heated before entering turbines to expand in the proposed system. A thermodynamic analysis of the proposed CAES is conducted on the basis of the process simulation. The overall efficiency and the efficiency of electricity storage are 48.37% and 81.50%, respectively. Furthermore, the exergy analysis is then derived and forecasted, and the exergy efficiency of the proposed system is 47.22%. The results show that the proposed CAES has more performance advantages than Huntorf CAES (the first CAES plant in the world). Techno-economic analysis of the coal-fired CAES shows that the cost of electricity (COE) is

Thermo-Dynamical Analysis on Electricity-Generation Subsystem of CAES Power Plant

106.33/MWh, which is relatively high in the rapidly developing power market. However, CAES will be more likely to be competitive if the power grid is improved and suitable geographical conditions for storage caverns are satisfied. This research provides a new approach for developing CAES in China.

An Improved CO2 Separation and Purification System Based on Cryogenic Separation and Distillation Theory

Compressed Air Energy Storage (CAES) is besides pumped hydropower, the other solution for large energy storage capacity. It can balance fluctuations in supply and demand of electricity. CAES is essential part of smart power grids. Linked with the flow structure and dynamic characteristic of electricity generation subsystem and its components, a simulation model is proposed. Thermo-dynamical performance on off-design conditions have been analyzed with constant air mass flux and constant gas combustion temperature. Some simulation diagrams of curve are plotted also. The contrast of varied operation mode thermal performance is made between CAES power plant and simple gas turbine power plant.