Compressed Air Energy Storage System Research Articles

Thermodynamic and economic analyses of a modified adiabatic compressed air energy storage system coupling with thermal power generation

With the proposal of "Carbon peaking and carbon neutrality", Adiabatic Compressed Air Energy Storage (A-CAES) has emerged as a significant component within China's energy storage infrastructure. But its thermodynamic efficiency and economical return need yet to be raised. The present paper proposed a modified system coupling with thermal power plant to utilize the excess compression heat. Utilizing advanced transient modeling software, an A-CAES plant is modeled and validated. The operation performance of the coupled system is compared with non-coupled system, which shows that the system efficiency is raised from 54.8 % to 76.7 % and the investment return rate is improved from 9.18 % to 10.43 %.

Effect of geothermal heat transfer on performance of the adiabatic compressed air energy storage systems with the salt cavern gas storage

The temperature and pressure of compressed air influence the output performance of the adiabatic compressed air energy storage system with salt cavern gas storage. However, current studies often overlook the impact of geothermal heat transfer on system performance. In this paper, a mathematical model of the energy storage system with salt cavern gas storage is developed, considering the geothermal heat transfer in wellbore and salt carven. The model is used to illustrate the effects of geothermal heat transfer on the system performance through a sensitivity analysis of some key parameters. The results show that geothermal heat transfer will significantly reduce the gas and energy storage capacity, with a maximum reduction of 15.3 % and 11.1 % at a depth of 2000 m, respectively. Furthermore, this reduction would increase with the depth of the salt cavern. The geothermal energy reduces the round-trip efficiency from 68.7 % to 66.26 % and the energy storage density from 5.18 kWh·m−3 to 4.32 kWh·m−3. For common salt cavern gas storage at a depth of about 600 m ∼ 1200 m, the negative impacts of geothermal heat transfer on round-trip efficiency and energy storage density are less than 2.2 % and 0.5 kWh·m−3, respectively. Sensitivity analysis also demonstrates that the primary factors influencing the system’s performance are the thermal conductivity of the surrounding rock, the volume of the salt cavern, and the length of the wellbores. The secondary factors include the heat transfer coefficient on the inner wall of the salt cavern, the inner pipe radius, and the roughness of the inner pipe. Irrelevant factors include the thermal conductivity of the protective fluid and the thermal conductivity of the cement layer. The proposed comprehensive mathematical model of the system and simulation findings aid in forecasting the performance of storage systems and offer theoretical guidance for the design of large-scale compressed air energy storage systems.

Performance analysis of a compressed air energy storage incorporated with a biomass power generation system

Compressed air energy storage technology is recognized as a promising method to consume renewable energy on a large scale and establish the safe and stable operation of the power grid. To improve the energy efficiency and economic performance of the compressed air energy storage system, this study proposes a design for integrating a compressed air energy storage system with a biomass power generation system. In the energy storage process, the feedwater from the biomass power generation system is used to cool the compressed air in the compressed air energy storage system. In the energy release process, the flue gas from the biomass power generation system is used to heat the compressed air. Besides, the compressed air from the compressed air energy storage system first works in the expander and then goes to the biomass power generation system for combustion. Based on the system simulation, the proposed system is assessed from the energy, exergy, economy, and environment perspectives. The results show that the round-trip efficiency and the energy storage density of the compressed air energy storage subsystem are 84.90 % and 15.91 MJ/m3, respectively. The exergy efficiency of the compressed air energy storage subsystem is 80.46 %, with the highest exergy loss in the throttle valves. The total investment of the compressed air energy storage subsystem is 256.45 k$, and the dynamic payback period and the net present value are 4.20 years and 340.48 k$. Besides, the proposed system’s CO2 emission is 258 kg/GWh. This study provides a new option for enhancing the performance of compressed air energy storage through the system integration.

Thermodynamic analysis of natural gas/hydrogen-fueled compressed air energy storage system

In this paper, a diabatic compressed air energy storage system fueled by a natural gas/hydrogen mixture that integrates heating and power generation is proposed. A comprehensive thermodynamic analysis has been conducted to identify the key factors influencing system performance and elucidate the detailed formation and distribution patterns of irreversible losses when utilizing a hydrogen-natural gas blend as fuel in the proposed system. The research results indicate that increasing the hydrogen blending ratio from 0.5 to 1 lead to greater enhancements in roundtrip efficiency (∼1.08% vs. ∼0.33%), exergy efficiency (∼3.88% vs. ∼1.15%), and energy density (∼1.24% vs. ∼0.42%) compared to an increase from 0 to 0.5. The combustor suffers the largest exergy destruction proportion, with a notable reduction in exergy destruction achieved through increased hydrogen blending. System performance benefits significantly from higher combustor outlet temperatures and expansion ratios at various hydrogen blending ratios. The rate of change in exergy efficiency (∼42.76% vs. ∼83.17%) and energy density (∼58.83%) demonstrates an inverse correlation with the varied parameters (1100–1500K, 4–8), except for the rate of change in energy density (∼6.76%), which displays a positive relationship with the combustor outlet temperature. Notably, a significant decrease in the rate of change in roundtrip efficiency (∼1.87% vs. ∼6.64%) is observed within a specific parameter range (1400–1500K, 5–6). Sensitivity analysis identifies the combustor outlet temperature as the most influential factor in enhancing system performance, consistently showing positive effects of the hydrogen blending ratio.

Status and Development Perspectives of the Compressed Air Energy Storage (CAES) Technologies—A Literature Review

The potential energy of compressed air represents a multi-application source of power. Historically employed to drive certain manufacturing or transportation systems, it became a source of vehicle propulsion in the late 19th century. During the second half of the 20th century, significant efforts were directed towards harnessing pressurized air for the storage of electrical energy. Today’s systems, which are based on storing the air at a high pressure, are usually recognized as compressed air energy storage (CAES) installations. This paper aims to provide an overview of different technologies that take advantage of the energy accumulated in the compressed air. Particular attention is paid to the CAES installations that are working as electrical energy storage systems (EESs). These systems, developed originally as large capacity (>100 MWe) and fuel-based installations, may soon become fully scalable, highly efficient, and fuel-free electrical energy storage systems. To present this opportunity, a thorough review encompassing previous and up-to-date advancements in their development was carried out. In particular, CAES concepts, such as diabatic (D-CAES), adiabatic (A-CAES), and isothermal (I-CAES), are described in detail. This review also provides the detailed characteristics of the crucial elements of these configurations, including compressors, expanders, air storage chambers, and thermal storage tanks. Knowledge of these components and their role allows us to understand the main challenges behind the further development of the mentioned CAES setups. Apart from the CAES systems that are designed as EES systems, this paper describes other prospective technologies that utilize the energy of pressurized air. Accordingly, compressed air cars and their key elements are explained in detail. Moreover, the technology renowned as wave-driven compressed air energy storage (W-CAES) is described as well, indicating that the utilization of pressurized air represents a viable option for converting ocean energy into electrical power.

A variable pressure water-sealed compressed air energy storage (CAES) tunnel excavated in the seabed: Concept and airtightness evaluation

For compressed air energy storage (CAES) caverns, the artificially excavated tunnel is flexible in site selection but high in sealing cost. A novel concept of building a water-sealed CAES tunnel in the seabed is proposed in this study, and the airtightness of the system is preliminarily evaluated. Based on the proposed variable pressure water-sealed CAES tunnel excavated in the seabed and combined with the actual operation of the system, a multifield and multiphase coupling calculation model for the airtightness calculation of water-sealed CAES tunnel under pressure changes was constructed, and the rationality of the model was confirmed by a case study. The airtightness analysis of the water-sealed CAES system is carried out. It is an effective method to excavate a tunnel in the seabed, and sealing the CAES system by utilizing the water head pressure in the pores of the rock mass and the low permeability of the rock mass. To satisfy the sealing requirements of the CAES system, the seawater depth of the tunnel should be deeper than 190 m if the gas pressure inside the tunnel is 4.5–10.0 MPa with the rock mass permeability of 1.0 × 10-16 m2 and the overlying rock thickness of 100 m, When the gas pressure inside the tunnel is 4.5–10.0 MPa, the overburden thickness is 100 m and the seawater depth is 50 m; the rock mass permeability should be less than 7.32 × 10-17 m2.

Solution for Post-Mining Sites: Thermo-Economic Analysis of a Large-Scale Integrated Energy Storage System

The intensive development of renewable energy sources and the decreasing efficiency of conventional energy sources are reducing the flexibility of the electric power system. It becomes necessary to develop energy storage systems that allow reducing the differences between generation and energy demand. This article presents a multivariant analysis of an adiabatic compressed air energy storage system. The system uses a post-mining shaft as a reservoir of compressed air and also as a location for the development of a heat storage tank. Consideration was given to the length of the discharge stage, which directly affects the capital expenditure and operating schedule of the system. The basis for the analyses was the in-house numerical model, which takes into account the variability of air parameters during system operation. The numerical model also includes calculations of Thermal Energy Storage’s transient performance. The energy efficiency of the system operating on a daily cycle varies from 67.9% to 70.3%. Various mechanisms for economic support of energy storage systems were analyzed. The levelized cost of storage varies, depending on the variant, from 75.86 EUR/MWh for the most favorable case to 223.24 EUR/MWh for the least favorable case.

Investigation and improvement of complex characteristics of packed bed thermal energy storage (PBTES) in adiabatic compressed air energy storage (A-CAES) systems

With the application of large-scale renewable energy, power grids have put forward explicit demands for energy storage. Among the various forms of energy storage systems, the adiabatic compressed air energy storage (A-CAES) system has received more attention due to its environmental friendliness and adaptability. As a key link in the regenerative A-CAES, thermal energy storage (TES) has an important impact on the efficiency of the system. Among various forms of TES, PBTES has better economy and adaptability. However, there is insufficient research on the impact of PBTES structure on A-CAES systems. Therefore, a dimensionless governing equation for the PBTES is proposed to study the depth effect of the PBTES structure. Through comparing with the pilot-scale and industrial-scale PBTES experimental data, the maximum error of the model is 2.3%, which proves that the model has good accuracy in the simulation of different scales of PBTES. The result of research shows that: the improved thickness of the structural layer is between 0.1 m and 0.15 m. The increase in the number of cycles of the A-CAES system results in a gradual increase in system efficiency. For the A-CAES system, the round-trip efficiency is improved by 4.1%, reaching 64%, with the improvement of the wall, volume ratio, and height-to-diameter ratio of PBTES.

Aerodynamic performance and flow field losses analysis: A study on nozzle governing turbine with varied regulated nozzle stator installation angle

During the energy release process in compressed air energy storage (CAES) system, the air storage pressure gradually diminishes. To optimize turbine performance in this scenario, a judicious air distribution method becomes imperative. This study adopts single nozzle governing method and elucidates the variation in aerodynamic characteristics under rated output work conditions by manipulating regulated nozzle stator installation angle (RNSIA) and total inlet pressure under varying base pressure. When the RNSIA ranges from −10° to 4° under the base pressure of 10.0 MPa, the maximum specific work increment is 13.2 % and efficiency increment is 14.3 % compared with throttle governing. Meanwhile, the maximum specific work increment is 4.0 % and efficiency increment is 2.9 % compared with designed RNSIA. The proportion of throttle entropy increase to the system progressively rises from 5 % to 40 %, mirroring the trend in system entropy increase. To maintain output work requirements, it's advisable to appropriately decrease the RNSIA to boost inlet pressure of the regulated nozzle and mitigate throttling losses. Additionally, the reduction in the RNSIA within a certain range prolongs the duration of the energy release process in the CAES system, which effectively enhances the round-trip efficiency of the CAES system.

Erratum to “Characteristics of the axial compressor with different stator gaps in compressed air energy storage system”

Erratum to “Characteristics of the axial compressor with different stator gaps in compressed air energy storage system”

Thermodynamic and techno-economic evaluation of a CAES based cogeneration system integrated with high-temperature thermal energy storage and ammonia absorption refrigeration

The development of compressed air energy storage (CAES) technology can ensure the safe and stable operation of the power system, promote the consumption of renewable energy and reduce carbon emissions. In order to improve the comprehensive performance of the CAES system and meet the diversified demand of energy, a cooling, heating and power cogeneration system based on compressed air energy storage with high temperature thermal energy storage and ammonia absorption refrigeration are developed in this study. The compression heat of the energy storage process and the exhaust waste heat of the energy release process are fully utilized in this system. Thermodynamic analysis, techno-economic evaluation and parametric analysis are conducted. The thermodynamic analysis results show that the proposed system achieve an ENE of 81.51 %, an EXE of 53.51% and an ESD of 7.08 kWh/m3 under the design condition. The economic analysis results indicate that the NPV, IRR and LCOE for a system life of 25 years are 489497 $, 32.1 % and 0.0953 $/kWh, with a DPP of 3.91 years. Sensitivity analysis results conclude that the outlet temperature of HTTES, and the maximum and minimum operating pressures are the key parameters affecting the system performance.

Maximizing Efficiency in Compressed Air Energy Storage: Insights from Thermal Energy Integration and Optimization

Motivated by the suboptimal performances observed in existing compressed air energy storage (CAES) systems, this work focuses on the efficiency optimization of CAES through thermal energy storage (TES) integration. The research explores the dependence of CAES performance on power plant layout, charging time, discharging time, available power, and cavern volume. Hence, a range of solutions are examined, encompassing both solid and liquid TES options, alongside the potential utilization of external air heaters. Inefficiencies in solid TES due to significant retention of thermal power within the medium after complete discharge are identified and mitigated through optimization strategies. In addition, solutions to prevent ice formation at the low-pressure expander phase are suggested to avoid icing issues in CAES layouts with liquid TES. Through this comprehensive investigation, the study provides valuable insights into enhancing the efficiency and sustainability of CAES systems. By constructing a volume–power–time conversion table, the research contributes to the advancement of CAES technology, facilitating more efficient energy storage and utilization, thereby addressing critical challenges in the field of energy storage.

Design Strategy of Diagonal Compressors in Compressed Air Energy Storage System

Design Strategy of Diagonal Compressors in Compressed Air Energy Storage System

A hydrogen-fuelled compressed air energy storage system for flexibility reinforcement and variable renewable energy integration in grids with high generation curtailment

Globally, the increasing share of renewables, prominently driven by intermittent sources such as solar and wind power, poses significant challenges to the reliability of current electrical infrastructures, leading to the adoption of extreme measures such as generation curtailment to preserve grid security. Within this framework, it is essential to develop energy storage systems that contribute to reinforce the flexibility and security of power grids while simultaneously reducing the share of generation curtailment. Therefore, this study investigates the performance of an integrated photovoltaic-hydrogen fuelled-compressed air energy storage system, whose configuration is specifically conceived to enable the connection of additional intermittent sources in already saturated grids. The yearly and seasonal performance of the integrated energy storage system, specifically designed to supply flexibility services, are evaluated for a scenario represented by a real grid with high-variable renewables penetration and frequent dispatchability issues. Results show that the integrated system, with performance-optimized components and a new energy management strategy, minimizes photovoltaic energy curtailment, otherwise around 50%, to as low as 4% per year, achieving system efficiencies of up to 62%, and reinforces the grid by supplying inertial power for up to 20% of nighttime hours. In conclusion, the integrated plant, operating with zero emissions, on-site hydrogen production, and optimized for non-dispatchable photovoltaic energy utilization, proves to be effective in integrating new variable renewable sources and reinforcing saturated grids, particularly during spring and summer.

Parameter impact and sensitivity analysis of a pumped hydro compressed air energy storage system

Pumped hydro compressed air energy storage systems are a new type of energy storage technology that can promote development of wind and solar energy. In this study, the effects of single- and multi-parameter combination scenarios on the operational performance of a pumped compressed air energy storage system are investigated. The impacts of 11 design parameters on the evaluation indices are explored, and the local sensitivity of each parameter is determined. Five key design parameters are selected and the global sensitivity under two-, three-, four-, and five-parameter combination scenarios are revealed. Finally, the energy and exergy flow processes in the original and seven preferred scenarios are compared and analyzed. The results show that the larger the pump efficiency, turbine efficiency, and cylinder 1 upper side cross-sectional area, and the lower the initial pressure, the higher is the ηRTE and ηX. For ED, the sensitivity of the termination air pressure is the highest, reaching 0.747. In scenarios where all three indices are increased, the maximum values of 0.586, 0.691, and 0.313 kW h/m3 are achieved for ηRTE, ηX, and ED, respectively.

Economic enhancement and grid‐frequency control of a wind farm‐CAES‐fuel cell‐based hybrid system

AbstractIn the present era, the electrical network faces difficulty owing to the restricted supply of conventional energy resources. Solar and wind power are supremely acceptable renewable energy around the globe due to their cheap availability, zero fuel costs, and environmental safety features. Maintaining power balance in a renewable combined day‐ahead power network becomes challenging owing to the uncertainty of renewable sources, resulting in economic instability. An energy‐storing device is essential for combining renewable sources with existing thermal power plants to control the energy supply and maintain system stability. Any government agency in the deregulated market does not set up energy pricing. The ISO (independent system operator) is the primary organization in the day‐ahead power network that is responsible for collecting energy bids from DISCOs (distribution companies), TRANSCOs (transmission companies), and GENCOs (generation companies). The energy pricing is set by the market regulator at a rate known as Location‐based marginal pricing (LBMP), which provides benefits to GENCOs, and DISCOs as well as the customers. In a deregulated market, the unpredictability of renewable sources affects system profit owing to the creation of instability cost (ISC), induced by mismatching the bidding power production from the renewable plant. To lessen these concerns, the presented approach has proposed an innovative model that employs ideal scheduling of the WF (wind‐farm)‐CAES (compressed‐air‐energy‐storage)‐fuel cell (FC) hybrid systems to enhance system economic profitability while keeping the grid frequency (GF) in the safe zone. The fuel cell acts as the energy‐storing device that can be utilized during high‐demand times on the grid, with the ultimate goal of maximizing profits for the overall system. The CAES system's energy level is separated into four dissimilar points, and this study presents an optimum approach for efficiently using it to maintain grid frequency. The new strategy outperformed the previous methods in all categories. The study was performed using the IEEE 30 bus test system.

Adiabatic Compressed Air Energy Storage system performance with application-oriented designed axial-flow compressor

Medium and long-duration energy storage systems are expected to play a critical role in the transition towards electrical grids powered by renewable energy sources. ACAES is a promising solution, capable of handling power and energy ratings over hundreds of MW and MWh, respectively. One challenge with ACAES is achieving the required highly efficient operation in the compressor over the range of conditions encountered in the system as the pressure in the air store changes. In this paper, an application-oriented axial-flow compressor is designed, aiming towards efficient operation throughout the operation range, whilst also associating the performance prediction to a practical compressor geometry. A two-step design methodology based on inviscid, axisymmetric flow conditions has been implemented, leading to the flowtrack, blade-row geometries and the compressor performance map. The compressor model is integrated into an ACAES model, including two compression spools, two expansion stages with preheat, a constant volume high pressure storage operating between 5.5 and 7.7 MPa and two separate Thermal Energy Storage units. While the existing ACAES literature either ignores the transient off-design operation or uses generic numerical correlations (which are not associated to a particular geometry), the key novelty of this paper is the application of a detailed design method for turbomachinery to ACAES. The results indicate that the designed compressor requires 33 stages over the two spools, and is able to operate efficiently over the storage pressure range, showing that if the application-oriented design procedure is applied to the compressor, it does not stop ACAES reaching 70% round-trip efficiency, outputting 35MW for approximately 15 h. Importantly, the specific ACAES requirement of conserving heat at higher temperatures has been fulfilled by decreasing the number of intercoolers. Finally, it is recommended that a similar level of scrutiny is applied to the other components (i.e. expanders, heat exchangers and TES units), keeping in mind the unique set of operational requirements of ACAES. This work is an important step towards removing the common misconception that off-the-shelf components can be easily be used in typical ACAES designs.

Energy and exergy analysis of a novel pumped hydro compressed air energy storage system

Many pumped hydro compressed air energy storage systems suffer from defects owing to large head variations in the hydraulic machinery. To solve this problem, this study proposes a novel pumped hydro compressed air energy storage system and analyzes its operational, energy, and exergy performances. First, the composition and operating principles of the system are analyzed, and energy and exergy models are developed for each module. Second, the operational characteristics of each module during the charging and discharging processes are analyzed. Finally, the energy and exergy performances of the system in single- and multi-cycle charging and discharging processes are revealed. The results show that the water pressure potential energy transfer module (module 2) effectively converts the pressure variation of nearly 1.6 MPa in the air storage tank to a head variation of 58.5 m during pumping and 48.2 m during power generation of the pumped storage unit. The electrical energy waste and exergy losses in module 1 are the highest, reaching 39.0% and 53.3%, respectively. After a single cycle, the efficiency, exergy efficiency, and energy storage density of the proposed system reach 59.0%, 70.1%, and 0.255 kW h/m3, respectively. After multiple cycles, the average efficiency increases to 62.5%.

Research on compressed air energy storage systems using cascade phase-change technology for matching fluctuating wind power generation

The wind speed varies randomly over a wide range, causing the output wind power to fluctuate in large amplitude. An isobaric adiabatic compressed air energy storage system using a cascade of phase-change materials (CPCM-IA-CAES) is proposed to cope with the problem of large fluctuations in wind farm output power. When the input power is lower than the minimum energy storage power of the compressor, the gradient phase-change thermal energy storage is utilized to broaden the operating range of the system. Second, the system design method and operation rules are elaborated. The storage/release characteristic curve is obtained by constructing the system components and the overall variable operating condition model. A matching system scheme is designed according to the characteristics of a wind farm in a port in China. The case study shows that the wind farm configured with the CPCM-IA-CAES system reduces the wind abandonment rate by 5.7%, recovers 4,644.46 kW h of wind power abandonment, and improves the storage power index by 16.67% compared with that of IA-CAES. Meanwhile, the system efficiency is increased from 65.96% to 74.68%, and the energy storage density is increased from 8.69 to 9.89 kW h m−3.

Improving Grid Reliability in Jordan: A Proposal for Integrated Demand Side Management and Energy Storage Solutions

<p align="left">Increased use of Renewable energy systems (RES) in Jordan has posed a major challenge in maintaining our grid stability. Jordan a country that relies on imported natural resources to power up its grid is using more and more RES with an aim to cut back on costs and CO<sub>2</sub> emissions. This paper investigates the usage of Demand Side Management (DSM) and Energy Storage Systems (ESS) to improve the grid’s reliability. A survey was conducted to analyze the opinion and acceptance of the Jordanian population on the implementation of DSM in Jordan. (ESS) mentioned in detail in this paper are: Compressed Air Energy Storage Systems (CAES), Superconducting Magnetic Energy Storage Systems(SMES), and Pumped Hydro Energy Storage Systems(PHES). The survey conducted showed a general scope of willingness of participation from people with 71.7% out of the 385 individuals who participated in the survey saying that they will participate in such a program if implemented in Jordan.</p>