Compressed Air Energy Storage Power Research Articles

Design of Underwater Compressed Air Flexible Airbag Energy Storage Device and Experimental Study of Physical Model in Pool

Renewable energy is a prominent area of research within the energy sector, and the storage of renewable energy represents an efficient method for its utilization. There are various energy storage methods available, among which compressed air energy storage stands out due to its large capacity and cost-effective working medium. While land-based compressed air energy storage power stations have been constructed worldwide, their efficiency remains low. Underwater compressed air energy storage has the potential to significantly enhance efficiency, although no such device currently exists. This paper presents the design of an UWCA-FABESD utilizing five flexible air bags for underwater gas storage and discharge. Additionally, it introduces the working principle of the adiabatic underwater compressed air energy storage system and device. Furthermore, a small-scale physical model with similar functionality was designed and manufactured to simulate the charging process of the air bag in onshore charging and discharging tests as well as posture adjustment and lifting arrangement tests, along with underwater charging and discharging tests. These experiments validated the related functions of the designed underwater compressed air flexible bag energy storage device while proposing methods for its improvement. This research provides a new approach to underwater compressed air energy storage.

Risk assessment of zero-carbon salt cavern compressed air energy storage power station

While exploiting natural resources, human beings have also left irreversible damage to the environment. The salt caverns left behind by the mining of salt are one of them. With the proposal of the “dual carbon” background, clean power and energy storage power stations have also become one of the focuses of sustainable development. The abandoned salt cavern is combined with the energy storage power station, and the excess electric energy is used to compress the air during the low power consumption period through the non-supplementary combustion mode, and the air kinetic energy is converted into electric energy during the peak power consumption period to realize the zero-carbon salt cavern energy storage conversion. This method can not only achieve zero carbon utilization of the abandoned environment, but also achieve energy storage and conversion, which is a very meaningful research. Based on spherical fuzzy sets, cumulative prospect theory and VIKOR, this paper constructs a novel combined research framework to analyze the risk of zero-carbon salt cavern compressed air energy storage (SAES) power station, and takes China ‘s first zero-carbon SAES power station project as an example. The results show that the overall risk of the zero-carbon SAES power station is 0.3467, which is a low risk. The key risks are non-supplementary combustion thermal energy storage technology risk, salt cavern creep and leakage risk, and the risk tolerance limit is +31.54 %.

Feasibility Analysis of Compressed Air Energy Storage in Salt Caverns in the Yunying Area

With the widespread recognition of underground salt cavern compressed air storage at home and abroad, how to choose and evaluate salt cavern resources has become a key issue in the construction of gas storage. This paper discussed the condition of building power plants, the collection of regional data and salt plant data, and the analysis of stability and tightness. Comprehensive analysis and evaluation methods were put forward from four aspects, including ground comprehensive conditions, regional geological conditions and formation lithology, salt mine characteristics, stability, and tightness of salt caverns. The limit equilibrium theory was applied to establish the limit equilibrium failure mode of salt caverns under operating pressure, and the stability coefficient calculation method of the target salt cavern was determined by combining the mechanical characteristics. Based on the physical and mechanical properties of salt rocks, it was found that salt rocks with enough thickness around the salt cavity could be used as sealing rings to ensure the tightness of the salt cavern. Combined with the field water sealing test, the tightness of the target salt cavern is verified. This method has been applied to the salt cavern screening and evaluation of a 300 MW compressed air energy storage power plant project in Yingcheng, Hubei Province, and remarkable results have been obtained, indicating the rationality of the method.

Study on characteristics of photovoltaic and photothermal coupling compressed air energy storage system

This paper studies the energy storage and generation characteristics of the photovoltaic power generation coupling compressed air energy storage system for the 5 kW base station, and analyzes the photovoltaic power generation characteristics within 24 h and its influence on the flow characteristics of the compressed air energy storage system. The results show that, affected by precipitation and sunlight, the compressed air energy storage power reaches highest value in May and August, and the compressed air flow and cooling water flow in a single day increase with the increase of light intensity. The power generation time reaches longest value in June, shortest in December, the energy storage time reaches longest in June and shortest in January. Considering the combined demand of cold energy, thermal energy and electric energy in actual production and life, the setting scheme of the compressed air energy storage system for combined cold heat power supply is obtained, and the parameter values such as compression/expansion stage, compression/expansion pressure ratio, temperature and pressure at the inlet and outlet of the compressor/expander/heat exchanger are defined. Adding solar thermal energy storage to the photovoltaic power generation compressed air energy storage system, it is found that it can effectively increase the air temperature and thus reduce the expansion stages required at a specific time.

Technical and economic analysis of energy storage in the compressed air technology with low capacity for the production plant

Compressed air energy storage (CAES) system is a promising technology due to its numerous advantages, including relatively low maintenance cost, a long lifespan and high operational flexibility. This article explores the possibility of designing a CAES power plant as a source of electricity and heat for an existing industrial plant. The study involves the technical analysis of the power plant parameters and the economic analysis of the project’s feasibility. The proposed power plant is an innovative solution with an air expander with an external combustion chamber and a bypass that allows the combustion of virtually any fuel, making it particularly environmentally friendly. In the system, the use of a combustion chamber at the outlet of the turbine makes the chamber operate at a constant pressure that is close to atmospheric pressure. The designed power plant has a capacity of approx. 3.1 MW. Turbine operation reaches an efficiency of about 76%. Additional modification of the power plant and the use of heat from compressor cooling could increase the power of the power plant by about 0.5 MW. The conducted financial analysis showed that the project is economically feasible under the adopted assumptions in three modeled scenarios. Under the most optimistic scenario, the internal rate of return (IRR) reached 14.27%, and the investment return time was 10 years. When using long-term energy prices data, it was 7.46% and 23 years, respectively. The proposed CAES system is original and competitive in comparison to the currently used solutions.

Design and Selection of Pipelines for Compressed Air Energy Storage Power Plants

The principle of Compressed-air energy storage is that the compressed air energy storage system uses compressed air as the energy storage carrier, which is a physical Energy storage that uses mechanical equipment to realize energy storage, transfer and utilization across time and space. At present, Compressed-air energy storage is the second largest technology that is considered suitable for GW level large-scale electric energy storage after pumped storage. Compressed air energy storage has outstanding advantages such as large scale, low cost, long service life, and short construction period. As a key link connecting compressors, expanders, and gas storage devices, the compressed air main pipeline has characteristics such as high operating pressure, low internal fluid temperature, large temperature difference between indoor and outdoor pipelines, and frequent start and stop. The design, calculation, and installation of the compressed air main pipeline will affect the economy and reliability of the entire system, and even bring serious destructive accidents. This article comprehensively introduces the selection method and process of compressed air energy storage pipeline design, and further verifies the feasibility and accuracy of the design method through case studies of specific projects. It provides convenience and calculation methods for the large-scale development of compressed air energy storage projects in the future[1].

Modality analysis and algorithm design of stator short-circuit fault set for large compressed air energy storage generators

Using salt caverns and caves to build compressed air energy storage power stations is an important development direction in the field of large-scale energy storage. With the continuous maturity of technology, compressed air energy storage generators have gradually developed into large-scale units with a single-unit capacity of 300 MW. Due to the increase of single-unit capacity, the internal short-circuit fault of the stator will cause very serious losses. In addition, the compressed air energy storage generator has complex operating conditions and is more prone to various internal short-circuit faults. In order to effectively ensure its safe and reliable operation, it is particularly necessary to study the effective main protection configuration scheme. The optimal design of the main protection configuration scheme is based on the analysis of the possible internal short-circuit faults of the generator. At present, the stator windings of large-scale compressed air energy storage generators generally adopt double-layer wave winding or double-layer tap winding structures. For these two winding structures, this paper analyzes in detail the characteristics of all fault modalities that may occur inside the large-capacity compressed air energy storage generator and designs a general algorithm that can form their respective fault sets. Finally, the application of the algorithm in the analysis of the stator fault modality in a compressed air energy storage power station is introduced.

Review of studies on enhancing thermal energy grade in the open ocean

Ocean thermal energy conversion is one of the important ways to utilize low-grade ocean thermal energy. The main reasons for its low economic feasibility include high cost, small temperature difference, low energy efficiency, and high consumption of deep-sea cold energy extraction pumps. Some new means to improve the thermal energy grade may be beneficial to improve the economic feasibility of ocean thermal energy conversion, desalination, and other systems. The research progress and analysis results of ways to obtain low-grade thermal energy in the ocean surface by using solar energy, offshore platform waste heat, compressed air storage waste heat, and other methods show that (1) after using solar energy or waste heat to raise sea water temperature, shallow seawater can be used as the cold source, which can reduce most of the pump consumption and expensive riser cost of lifting cold seawater. This way improves the net power generation efficiency more significantly than improving the circulation mode and working medium and also significantly improves the economic feasibility. (2) Exhaust waste heat from offshore platform diesel power generation and compressed air energy storage power generation systems can be used to obtain a larger temperature difference between cold and hot seawater and further improve the efficiency of thermal power generation. (3) The low density of solar energy flow at the sea level leads to the high cost of offshore platforms. Incorporating ocean thermal energy conversion systems into floating photovoltaic power generation, seawater desalination and other systems can reduce the cost of offshore platforms.

Long-term stability analysis and evaluation of salt cavern compressed air energy storage power plant under creep-fatigue interaction

To investigate the influence of the fatigue effect of salt rock on the long-term stability of the compressed air energy storage power plant, the numerical simulation method was used to analyze the long-term stability of the energy storage under the conditions of the fatigue effect is considered (the creep-fatigue interaction of salt rock stratum is considered) and not considered (only the creep behavior of salt rock stratum is considered). The numerical calculation results show that when the fatigue effect is considered, the deformation of the surrounding rock and the cavern volume shrinkage are far greater than the corresponding values when the fatigue effect is not considered, indicating that the fatigue effect has an important impact on the stability of the storage. Then based on the numerical simulation results, the minimum pressure, maximum pressure and pillar width of the salt cavern compressed air energy storage power plant were determined by contrasting the displacement of the surrounding rock, the cavern volume shrinkage and the extended range of the plastic zone. Finally, a long-term stability evaluation system for the salt cavern compressed air energy storage power plant was established based on the analytic hierarchy process method, and the long-term stability was quantitatively evaluated using the fuzzy evaluation method. The results show that the stability level of the double salt caverns compressed air energy storage power plant is Level II, indicating that they are in stable state.

China's national demonstration project for compressed air energy storage achieved milestone in industrial operation

On May 26, 2022, the world's first nonsupplemental combustion compressed air energy storage power plant (Figure 1), Jintan Salt-cavern Compressed Air Energy Storage National Demonstration Project, was officially launched! At 10:00 AM, the plant was successfully connected to the grid and operated stably, marking the completion of the construction of the first national demonstration project of compressed air energy storage in China in accordance with the commercial power station standards. After the successful completion of the continuous full-load energy storage-power generation test, it was officially put into operation to become a milestone in the development of new energy storage technologies in China.

Economical and Experimental Study of Hybrid Power System of Compressed Air Energy Storage with Photovoltaic Array and Wind Turbine Generator. (Dept. E)

This paper presents an economical and experimental study of large and small scales Compressed Air Energy Storage (CAES) integrated with PV array and wind turbine generator based on economic criteria. Two different CAES systems with three different case studies are presented in detail. The first model included wind turbine, compressor, and storage reservoir with different rating values, 220 MW, 200 MW, and 150,000 m3 for the turbine, compressor, and storage reservoir volume respectively. A small CAES power system consists of 5 KW isolated load fed by Bergey Excel-S 10 kW wind turbine is chosen as another application to investigate the effectiveness of the proposed presented model. The second presented model is based on real prototype testing and laboratory measurements supplied from a PV panel. A prototype model is built up in a small size to indicate the system characteristics and its main effective parameters. Furthermore, a case study on an isolated Egyptian village (Halayeb) is introduced as a third case study based on the basics of the proposed prototype system. The results prove the ability of the CAES system to supply domestic loads of a grid isolated village. Finally, the paper presented an economic analysis of the presented system.

Investigation of a combined heat and power (CHP) system based on biomass and compressed air energy storage (CAES)

Compressed air energy storage (CAES), owing to low geographical limitation, high reliability, and negligible environmental impact, has attracted attention in recent years, hybridizing with different types of renewable energies. Contrary to the other renewable energies such as solar and wind, biomass does not depend on the region's weather condition and is more reliable than other renewables, making it a promising solution for sustainable development. Therefore, a novel combined heat and power system based on biomass gasification, CAES, and gas turbine power plant is introduced in the present research and analyzed by using ASPEN PLUS. Three different kinds of biomass materials, including wood chips, green waste, and municipal solid waste are considered, and the effects of critical parameters on system performance are precisely investigated. The results showed that the syngas composition has no significant impact on the variation of steam and air temperature. However, the air temperature has a considerable indirect effect on the char split fraction. Comparing the effect of biomass materials on efficiency shows that Green waste is the least efficient material, while the MSW offers the highest total efficiency, and the highest power plant efficiency can be obtained by using the wood chips to produce syngas fuel. Consequently, the gasifier's maximum efficiency is obtained at a temperature of 960℃ and steam to biomass ratio of 1.

A multi-criteria decision-making framework for compressed air energy storage power site selection based on the probabilistic language term sets and regret theory

To promote the sustainable development of the energy economy and handle the intermittent problems of renewable energy power generation, compressed air energy storage (CAES) power generation has emerged. Site selection makes an important contribution to the success of CAES project and is a multi-criteria decision-making (MCDM) problem. This paper proposes a MCDM method based on probabilistic language term sets (PLTSs) and regret theory, and applies it to the site selection of CAES project. Firstly, this paper constructs an index system covering six criteria and sixteen sub-criteria. Secondly, PLTSs are used to describe the evaluation information of decision makers (DMs), which consider the hesitation of DMs and information uncertainty. And a new distance formula of PLTSs is defined. Thirdly, this paper considers the psychological characteristics of DMs by introducing regret theory, and further defines a comprehensive perceptual utility function to avoid the enlargement or reduction of the regret or rejoice value due to the ignorance of expected value of the plan itself. Fourthly, a weighting model of DMs weights is established by using the entropy weight method, and a criteria weight model is developed by minimizing distance deviation. Furthermore, a MCDM method is proposed. Finally, a case study is provided to verify the effectiveness and feasibility of our method. The results show that option A3 is the best choice. This work provides a scientific theoretical basis for the investment decision-making of CAES project.

Near constant discharge performance analysis of a dual accumulator configuration quasi-isothermal compressed gas energy storage based on condensable gas

Energy storage can provide flexibility on both power generation and consumption sides when large renewables penetrate, leading to a low-carbon society development. Although the compressed air energy storage (CAES) system usually emerges as a grid-scale energy storage facility, the small-scale CAES system, especially isothermal or quasi-isothermal CAES, with constant or near constant power output may be effective to provide urgent power for special load in some other occasions. Meanwhile, the isobaric process can be enlightened by the phase change of condensable gas at its saturation pressure. From this viewpoint, the near constant discharge performance analysis of a dual hydraulic accumulator configuration quasi-isothermal compressed gas energy storage based on condensable gas R41 is proposed in this paper. The methods of liquid piston and spraying liquid are adopted to realize a quasi-isothermal process. The phase change of condensable gas at saturation pressure and dual accumulator configuration are two measures to maintain the gas pressure lay in a narrow range, implying a near constant discharge. Based on the system transient model, the transient analysis of system components, parametric analysis, off-design analysis and variant system performance analysis are conducted. Results show that the system round trip efficiency (RTE) and energy density (ED) are 63.98% and 0.1175 kWh/m3, respectively. The power output is located in the range from 0.93 kW to 1.11 kW, which is relatively stable and around the 1 kW rated power. Moreover, the initial quality of R41 and volume of accumulator have effect on system performance. Meanwhile, the Pelton turbine power level can be adjusted by altering jets number and nozzle effective area.

System Configurations and Operational Concepts for Highly Efficient Utilization of Power-to-Heat in A-CAES

The increasing share of renewable energies requires the installation of large-scale electricity storage capacities in addition to grid expansion. Significant contribution to reach this goal is provided by adiabatic compressed air energy storage power plants (A-CAES), key elements in future electricity transmission systems. This technology allows efficient, local zero-emission electricity storage on the basis of compressed air in underground caverns in combination with thermal energy storage systems and, in contrast to pumped storage power plants (PSPP), it demands no overground geological requirements. Despite the achieved success of A-CAES systems in terms of efficiency and cost, further improvements in dynamics and flexibility are needed. One promising solution to fulfil these dynamic requirements is based on the integration of an additional power-to-heat element (P2H) operating during the charging periods. This modification allows increased power plant flexibility and further cost reductions due to increased thermal storage densities but is simultaneously associated with concept-dependent decreasing total round trip efficiencies. For the identification of suitable configurations, adequate concepts must be elaborated, and the influence on round trip efficiency as well as on cost reduction potential must be investigated. For this purpose, a system model for a two-stage A-CAES configuration is established and used for large simulation studies related to P2H locations and power, thermal energy storage systems, and central process variables. Therefore, time-efficient model reductions with well-justified assumptions are conducted, offering a simplified transient implementation of thermal energy options in the system simulation. On the basis of a promising P2H configuration including high potentials for cost reduction and moderate losses in round trip efficiency, an alternative concept is presented offering high exergetic utilization and additional cost reductions, which can be treated as a base for upgrading the existing CAES power plants and for modifying operational concepts.

Design and Operational Strategy Research for Temperature Control Systems of Isothermal Compressed Air Energy Storage Power Plants

Energy storage technology is critical for intelligent power grids. It has great significance for the large-scale integration of new energy sources into the power grid and the transition of the energy structure. Based on the existing technology of isothermal compressed air energy storage, this paper presents a design scheme of isothermal compressed air energy storage power station, which uses liquid to compress air, hydraulic piston to transfer potential energy, hydraulic turbine to generate electricity at constant pressure, and liquid occupancy to store the gas at constant pressure. Then the technical features and control strategies of its internal temperature control subsystem are studied, and the mathematical model is constructed. A hierarchical relay operation is put forward to address the actual construction and operational requirements of compressed air energy storage power plants. Finally, through physical platform experiments and MATLAB simulation, the feasibility of the design is validated.

Power-to-heat in adiabatic compressed air energy storage power plants for cost reduction and increased flexibility

The development of new technologies for large-scale electricity storage is a key element in future flexible electricity transmission systems. Electricity storage in adiabatic compressed air energy storage (A-CAES) power plants offers the prospect of making a substantial contribution to reach this goal. This concept allows efficient, local zero-emission electricity storage on the basis of compressed air in underground caverns. The compression and expansion of air in turbomachinery help to balance power generation peaks that are not demand-driven on the one hand and consumption-induced load peaks on the other. For further improvements in cost efficiencies and flexibility, system modifications are necessary. Therefore, a novel concept regarding the integration of an electrical heating component is investigated. This modification allows increased power plant flexibilities and decreasing component sizes due to the generated high temperature heat with simultaneously decreasing total round trip efficiencies. For an exemplarily A-CAES case simulation studies regarding the electrical heating power and thermal energy storage sizes were conducted to identify the potentials in cost reduction of the central power plant components and the loss in round trip efficiency.

The effect of key parameters on the design of an optimized caes power plant

Due to the significant variations in electricity generation and its demand, the power plant owners are encountered with challenges of economic operation. Among all, Compressed air energy storage (CAES) technology has proposed itself as a reliable and efficient solution to match the two sides. This paper deals with a modeled compressed air energy storage power plant which has been optimized thermodynamically through an efficient genetic algorithm code. The results of this optimized model, considered as the base case, show that the power plant is technically and financially justifiable. In order to obtain a more tangible realization, it is necessary to verify the results against the variation of key parameters. In this study, the sensitivity analysis is performed based on main parameters including plant loading and ambient condition and the resultant trends of each case are presented. This approach will help the designers to analyze the quality of their designs in different situations.

Geotechnical Feasibility Analysis of Compressed Air Energy Storage (CAES) in Bedded Salt Formations: a Case Study in Huai’an City, China

The lower reaches of the Yangtze River is one of the most developed regions in China. It is desirable to build compressed air energy storage (CAES) power plants in this area to ensure the safety, stability, and economic operation of the power network. Geotechnical feasibility analysis was carried out for CAES in impure bedded salt formations in Huai’an City, China, located in this region. First, geological investigation revealed that the salt groups in the Zhangxing Block meet the basic geological conditions for CAES storage, even though the possible unfavorable characteristics of the salt formations include bedding and different percentages of impurities. Second, mechanical tests were carried out to determine the mechanical characteristics of the bedded salt formations. It is encouraging that the samples did not fail even when they had undergone large creep deformation. Finally, numerical simulation was performed to evaluate the stability and volume shrinkage of the CAES under the following conditions: the shape of a single cavern is that of a pear; the width of the pillar is adopted as two times the largest diameter; three regular operating patterns were adopted for two operating caverns (internal pressure 9–10.5 MPa, 10–11.5 MPa, and 11–12.5 MPa), while the other two were kept at high pressure (internal pressure 10.5, 11.5, and 12.5 MPa) as backups; an emergency operating pattern in which two operating caverns were kept at atmospheric pressure (0.1 MPa) for emergency while the backups were under operation (9–10.5 MPa), simulated for 12 months at the beginning of the 5th year. The results of the analysis for the plastic zone, displacement, and volume shrinkage support the feasibility of the construction of an underground CAES power station.

Modeling of a Compressed Air Energy Electrification by Using Induction Generator Based on Field Oriented Control Principle

The objective of this paper is to propose a modelling of a small compressed air energy storage system, which drives an induction generator based on a field-oriented control (FOC) principle for a renewable power generation. The proposed system is a hybrid technology of energy storage and electrification, which is developed to use as a small scale of renewable energy power plant. The energy will be transferred from the renewable energy resource to the compressed air energy by reciprocating air compressor to be stored in a pressurized vessel. The energy storage system uses a small compressed air energy storage system, developed as a small unit and installed above ground to avoid site limitation as same as the conventional CAES does. Therefore, it is suitable to be placed at any location. The system is operated in low pressure not more than 15 bar, so, it easy to available component in country and inexpensive. The power generation uses a variable speed induction generator (IG). The relationship of pressure and air flow of the compressed air, which varies continuously during the discharge of compressed air to drive the generator, is considered as a control command. As a result, the generator generates power in wide speed range. Unlike the conventional CAES that used gas turbine, this system does not have any combustion units. Thus, the system does not burn fuel and exhaust pollution. This paper expresses the modelling, thermodynamic analysis simulation and experiment to obtain the characteristic and performance of a new concept of a small compressed air energy storage power plant, which can be helpful in system designing of renewable energy electrification. The system was tested under a range of expansion pressure ratios in order to determine its characteristics and performance. The efficiency of expansion air of 49.34% is calculated, while the efficiency of generator of 60.85% is examined. The overall efficiency of system of approximately 30% is also investigated.