Compressed air energy storage: efficient and cost effective

The goal of energy storage is to capture energy and deliver it efficiently for future use. Energy storage technologies offer several important advantages: improved power quality stability, reliability of power supply, etc. In recent years, as the energy crisis has intensified, energy storage has become a major focus of research in both industry and academia. There are various methods to store energy, such as mechanical, electrical, chemical, electrochemical and thermal.

Energy storage technologies will play a crucial role in increasing both the efficiency and availability of renewable energy. Compressed air energy storage (CAES) enables efficient and cost-effective storage of large amounts of energy, typically above 100 MW.

However, this technology is limited by the risks inherent in subway exploration. To reduce this disadvantage, we propose a mini-CAES concept where the cavity is shallower than the current CAES. This concept redefines energy storage capacity with storage capacity power in the range of 10 to 100 MW, thus minimizing the impact on the surface and making it less expensive than conventional CAES. The findings describe the technical parameters to be considered for mini-CAES and the relationship of these to energy storage capacity.

As a result of this study, the subsurface infrastructure and its interactions with surface and energy conditions have been optimized. Mini-CAES is more suitable for renewable energy than deeper CAES.

Compressed air energy storage (CAES) is based on the gas turbine cycle. Surplus energy is used to compress air using a rotary compressor and then stored, often in a subway chamber. When power is required, it is released from the chamber and passes through an air turbine that generates electricity from the high-pressure air flow. The plant’s output can be increased by burning natural gas in the high-pressure air before it enters the air turbine, as would happen in a conventional gas turbine. However, this has the penalty of producing carbon dioxide emissions, which is not the case with the simple storage plant. More advanced plants can store heat during air compression and release it during the expansion phase. Only two commercial CAES plants have been built.

Compressed air energy storage (CAES) plants operate with motors driving compressors, which compress air for storage in suitable containers. The energy stored in the compressed air can be released to drive an expander, which in turn drives a generator to produce electricity. Compared to other energy storage (ES) technologies, CAES plants have very large power and storage capacity, low self-discharge and long service life. These attributes make it the most promising and cost-effective method for large-scale ES grid services. Conventional CAES plants have relatively low round-trip efficiency; however, research studies on more advanced CAES concepts, such as adiabatic and isothermal CAES, seek to improve it. The world has a large underground compressed air storage capacity, which means that CAES could provide a significant amount of the world’s future electric power needs. This chapter outlines the operating principles of CAES, compares CAES to other electric power technologies, lists the grid services for which CAES is best suited, presents advanced CAES designs and current projects, discusses exergy analysis of CAES plants and components, reports on the worldwide potential of CAES, and offers research directions and future challenges.

Energy Storage Systems are key to improving the load factor of renewable energy. miniCAES describes shallower subway infrastructures for energy storage. The cavity was defined, as well as the impact of the installation on the surface. miniCAES reduces the risk of exploration and a better adaptation to renewable energies. The miniCAES system allows energy to be managed in an economically cost-effective manner.

Compressed air energy storage system (CAES) is one of the highly efficient and low capital cost energy storage technologies, which is used on a large scale. However, due to multiple operational and technical constraints, CAES operation must be incorporated with thermodynamic characteristics. Therefore, in this paper, the novel thermodynamic modeling of the CAES facility integrated with the hybrid thermal, wind and photovoltaic (PV) farms is investigated to participate in the power and reserve markets. The consideration of thermodynamic characteristics makes the proposed scheduling more realistic, while imposing multiple constraints on the optimal operation of the hybrid system. The operation of the CAES system during both charging and discharging modes is analyzed simultaneously, considering thermodynamic characteristics, and the cavern state of charge is calculated for both modes. In addition to considering thermodynamic characteristics, the recovery cycle capability is integrated so that the CAES facility recovers heat from the turbine in the preheater, resulting in higher turbine efficiency. The proposed scheduling of the hybrid system is exposed to a high level of uncertainty caused by energy and reserve market prices, as well as fluctuating wind farm and PV power output. Therefore, the scenario-based stochastic approach is applied based on real historical data from the KHAF station in IRAN to handle the existing uncertainties. Numerical results are provided for different cases. The main conclusions of the numerical results show the effectiveness of the recovery cycle from improving the cost-effectiveness and reducing the fuel burned up to 11.36 % and 11.33 %, respectively.