Performance Of Compressed Air Energy Storage Research Articles

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.

Experimental investigation on the performance of compressed air energy storage using spray-based heat transfer

Near-isothermal compression and expansion may be accomplished by injecting water droplets into the air during the process to increase the overall efficiency. However, little is known about the relationship between spray system parameters and compressed air energy storage (CAES). Furthermore, the experiments about compressed air energy storage using spray-based heat transfer have not been investigated. The aim of this paper is to study the relationship between the performance of CAES and the spray system parameters by experimentally. The parameters including the spray closing time, the spray opening time, and the nozzle diameter are discussed. Results show that under the same operating conditions, the maximum air pressure in compression chamber reach to constant value when the spray closing time is 0.6 s; and spraying water mist within 0.6-1.2 s has no heat exchange effect on the air in the cylinder. During the compression process, the smaller the nozzle diameter is, the higher maximum pressure in compression chamber is. During the expansion process, if we ignore the energy consumption of spray system, the larger the nozzle diameter is, the more the expansion output is. Further investigation is recommended to optimize spray parameters based on different CAES systems.

Energy analysis and economic evaluation of trigeneration system integrating compressed air energy storage system, organic Rankine cycle with different absorption refrigeration systems

In recent years, a concerted effort has been made to reduce reliance on conventional fossil fuels by advancing the use of renewable energy. Nonetheless, the use of renewable energy presents inherent challenges, prominently including intermittency and unpredictability. These obstacles impede the seamless integration and optimal use of renewable energy. A promising solution to address the issues of intermittency and unpredictability in renewable energy is compressed air energy storage (CAES) technology. The performance of CAES can be significantly enhanced through the implementation of a trigeneration system. Some studies have been performed to develop strategies in order to improve the round-trip efficiency (RTE) of the CAES. However, no studies have evaluated the effect of integrating different types of absorption refrigeration systems (ARSs) (different effects and different working media). Steady-state models for CAES, organic Rankine cycle (ORC) and different types of ARSs were developed in Aspen Plus®. All the models were validated in Aspen Plus®. Then process study was conducted to analyse the effects of recuperator outlet temperature and ARS mass flowrate on CCHP system performance. Economic evaluation was performed using Aspen Process Economic Analyser® (APEA). The double-effect ARS is superior to single-effect ARS with the same working medium. The LiBr-H2O is more suitable than NH3-H2O as working medium. The CCHP implemented with double-effect ARS using LiBr-H2O can produce 206 MWe of electrical energy, 7.26 MWth of heating and 27.28 MWth cooling capacity with coefficient of performance (COP) 1.36. The process analysis indicates that COP and RTE increased with the ARS mass flowrate. The levelized cost of electricity (LCOE) of the CCHP-3 system is 31.01 $/MWh, the payback period of the CCHP-3 system is 12.9 years. Overall, this first systematic study comparing different types of ARS for the CCHP system will provide important guidance on the process design and analysis of CCHP.

Comparison of the characteristics of compressed air energy storage in dome-shaped and horizontal aquifers based on the Pittsfield aquifer field test

Most studies have suggested that aquifers with anticlinal structures are the most favorable structures for compressed air energy storage (CAES) in aquifers because of their trapping ability, but this limits the potential locations for CAES plants, as horizontal aquifers are very common only in offshore areas rich in wind power. The comparison of the characteristics of CAES in dome-shaped and horizontal aquifers can help in understanding the quantitative differences between them. In this study, based on Pittsfield aquifer field test strata and parameters, the characteristics of CAES in dome-shaped and horizontal aquifers were investigated using a numerical simulation method by establishing two comparable conceptual models of a dome-shaped aquifer and a horizontal aquifer. Reasonable matches between the monitored data and simulated results were obtained for the initial air bubble development period of the Pittsfield aquifer field test. Comparisons of the initial air bubble, air cycling performance and energy recovery efficiency were carried out with the same calculation settings for the dome-shaped and horizontal aquifers. In the initial air bubble development period, when the same air volume was injected into the dome-shaped and horizontal aquifers, the radius of the air–water interface in the horizontal aquifer was 16.7% larger than that in the dome-shaped aquifer. In the air cycling period, an isothermal cycle type with a constant injection and production air pressure was designed. The energy recovery efficiency of CAES in aquifers is calculated in terms of the concept of exergy. In the case of isothermal compressor work and ignoring the energy loss in the compressor system, the energy recovery efficiency of the horizontal aquifer can reach approximately 80% of that in the dome-shaped aquifer. The effects of wellbore injection/production length and circulation mode on the performance of CAES in both aquifers were investigated. Wellbore injection/production length has obvious impacts on air mass flow rates during initial air bubble development and subsequent cycling, and a longer wellbore injection/production length can provide greater capacity. A comparison between the daily and weekly circulation periods in the dome-shaped and horizontal aquifers showed that the daily circulation has an efficiency advantage at the same energy storage scale, and the energy recovery efficiency of the horizontal aquifer in the weekly circulation can reach approximately 74% of that of the dome-shaped aquifer. In addition, a constant flow rate injection/production gas daily cycle mode was investigated, and the results showed that this mode has higher energy recovery efficiency than the constant pressure cycle mode, and the horizontal aquifer can reach 88.39% of the efficiency of the dome-shaped aquifer. The comparison of the characteristics of CAES in dome-shaped and horizontal aquifers shows that horizontal aquifers may be a potential choice for the storage media of CAES in the case that there are no suitable aquifers with anticlinal structures in offshore areas.

An innovative rearrangement and comprehensive comparison of the combination of compressed air energy storage (CAES) with multi stage flash (MSF) desalination and multi effect distillation (MED) systems

Energy and drinkable water are the two critical resources for the world population. Compressed air energy storage (CAES) is one of the best solutions for grid-scale electricity power storage. Besides different technologies of desalination have been proposed until now. Comprehensive scrutiny of an integrated CAES-Desalination has been proposed in this study. This system can produce drinkable water and electricity power at the same time which makes it an ideal system in dry and warm environments. Multi-effect distillation and Multi-stage flash have been simulated and compared as desalination units. CAES system's dissipated heat is consumed as the input heat power of the desalination unit. In this way not only a large amount of potable water is produced but also the CAES performance is improved. The desalination required heat power is supplied in both charging and discharging mode from the compressors' heat exchanger secondary stream and turbine exhaust hot air respectively. The novelty of this paper is in the simulation of the CAES, MED, and MSF systems separately and thoroughly Comparing MED-CAES and MSF-CAES systems and also proposing a new arrangement for CAES-Desalination systems, and analyzing the effect of omitting the CAES system's recuperator and its consequence on system total outputs. The results for this case showed an almost 3 % improvement in roundtrip efficiency in comparison to the one with a recuperator. Also, the distilled water rate is almost 2.5 times of the normal CAES-Desalination system.

Thermodynamic modeling of compressed air energy storage for energy and reserve markets

Compressed air energy storage (CAES) system 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 limitations, the CAES operation should be incorporated with thermodynamic characteristics. Therefore, in this paper, novel thermodynamic modeling of CAES facility integrated with the hybrid thermal, wind, and photovoltaic (PV) farms to participate in energy and reserve markets is investigated. Considering the thermodynamic characteristics makes the proposed scheduling more realistic, while imposes multiple constraints on the optimal operation of the hybrid system. The operation of the CAES facility during charging and discharging modes, considering thermodynamic characteristics are analyzed simultaneously, and the state of charge of the cavern is calculated for both modes. In addition to taking into account the thermodynamic characteristics, the recovery cycle capability is embedded for the CAES facility to recover heat from the turbine in the preheater results in increased turbine efficiency. The proposed scheduling of the hybrid system is exposed by high-level uncertainty caused by energy and reserve market prices, as well as wind and PV farms power fluctuation. Hence, the scenario-based stochastic approach is applied based on real historical data of the KHAF station in IRAN to handle existing uncertainties. Numerical results are provided for different cases. The major conclusions of the numerical results show the effectiveness of the recovery cycle from profit improvement and burned fuel reduction up to 11.36% and 11.33%, respectively, while the thermodynamical constraints in the CAES performance make the realistic model, compared with the conventional CAES.

Implementation of Transient Stability Model of Compressed Air Energy Storage Systems

This paper discusses the implementation of a transient stability model of Compressed Air Energy Storage (CAES) systems in a power system analysis package. A block-diagram based model of a two-machine CAES system is proposed, including specific controls for active power, reactive power, and State of Charge (SoC), which consider limits associated with the cavern pressure. As an application, the model is implemented in Powertech's TSAT software connected to the 9-bus WSCC benchmark power system, which is then used to study the impact of a CAES facility in the transient and frequency stability of the system. Several contingencies are simulated comparing the CAES performance to a gas turbine and a base-case without storage, demonstrating that the CAES system improves the system transient stability due to its charging stage, controls, and additional inertia. Finally, the CAES model is used to study the effects of cavern sizes in the frequency of the system. It is shown that CAES systems have certain special characteristics that make them attractive as a storage technology to provide stability and regulation services, besides their energy arbitrage capabilities.

Transmission characteristics of exergy for novel compressed air energy storage systems-from compression and expansion sections to the whole system

Exergy flow characteristics of novel compressed air energy storage (CAES) is significant to evaluate CAES performance while few literatures have addressed this topic. The exergy flow characteristics of two cutting edge CAES systems, compressed air energy storage systems with thermal energy storage (TS-CAES) and supercritical compressed air energy storage (SC-CAES) systems are studied in this paper. All processes of the two systems are modeled (compression section, expansion section, air storage section for TS-CAES and cold storage/liquefaction section for SC-CAES) based on the commonness of the two systems. Exergy is decomposed into thermal and mechanical exergy for their different flow directions and characteristics. Thus, a general exergy flow model for the two systems was established. With the general model, the variations of the relevant proportional ratios and exergy transfer efficiencies with key parameters are revealed. Meanwhile, the energy coupling mechanism for the two systems are explored as well. For TS-CAES systems, except for the number of parts, the variation of each parameter only dominates the change of exergy transfer efficiency of a certain term or some two. All the variables except the pressure loss coefficient of the intercooler and the polytropic efficiency of the compressor, have large effect on the thermal exergy transfer efficiency of their respective flow section. For SC-CAES systems, with the increase of energy storage/release pressure, the system efficiency increases first and then decreases, which is due to change of liquefaction ratio.

Microfluidic Study on the Two-Phase Fluid Flow in Porous Media During Repetitive Drainage-Imbibition Cycles and Implications to the CAES Operation

Compressed air energy storage (CAES) technology has been re-emerging as a viable energy storage option to address challenges coming from the mismatch between renewable energy sources and energy demands. Various geologic formations, such as hard rock caverns, depleted oil/gas reservoirs, and saline aquifers, have been considered as the alternative of salt dome caverns for CAES. Storing compressed air in either depleted oil/gas reservoirs or saline aquifers involves two-phase fluid flow in porous media. Moreover, the drainage-imbibition process is likely to be repeated numerous cycles during the CAES operation. In this regard, a thorough understanding of the two-phase fluid flow during the cyclic injection and withdrawal of compressed air is critical to predict the performance of CAES in porous media and to improve its efficiency. This study investigates the repetitive two-phase fluid (water/oil) flow using polydimethylsiloxane-based pore-network micromodels. Two different geometries, Type I with circular solids and Type II with square solids were prepared to represent an unconsolidated and/or partially consolidated sandstone and a fracture network of carbonate rock. During repetitive drainage-imbibition cycles, it was observed that the occupation efficiency of the non-wetting fluid (water) converged to a narrow range for Type I model, while it showed a pronounced fluctuation for Type II, which was partly due to the low residual saturation of the non-wetting fluid during the imbibition process. Besides, the prevalent displacement modes of wetting and non-wetting fluids at the pore-scale were noticeably different between the two pore structures, which were manifested in the unpredictable pattern of non-wetting fluid flow for Type II over the extended cycles. Sweep efficiency and residual saturation in Type I were greater than those in Type II; however, an analysis of effective sweep efficiency and effective residual saturation yielded an opposite result. It implies that the actual efficiency of non-wetting fluid invasion is higher in Type II, and the Type II geometry can accommodate more non-wetting fluid in a given reservoir volume during the charge period. Moreover, more non-wetting fluid can be discharged back for energy regeneration. In conclusion, the geometry of porous media has a great influence on the efficiency of repetitive drainage-imbibition cycles of two-phase fluid flow in porous media, and thus more elaborate study is needed to gain the confidence on the cyclic efficiency of CAES in porous media.

Thermodynamic Analysis of Compressed Air Energy Storage with Integration of Wind Power

Integration of wind farm (WF) into the power grid system (PGS) will reduce the use of fossil fuels as well as minimize the greenhouse emissions. However, due to variableness of wind energy, the control and stability of PGS become more complicated. Compressed air energy storage (CAES) is one of the energy storage system (ESS) technology which can mitigate the fluctuation of renewable energy sources (RESs) due to some advantages such as quick start-up time and a large storage capacity size. This paper presents a modeling and simulation of CAES integrated with wind farm (WF-CAES) to investigate the thermodynamic performance of CAES on both compression and expansion modes during adiabatic and isothermal processes. Simulation results show that the wind speed and compressor efficiency plays a vital role in improving the overall system efficiency during the compression mode while the flow of air and the storage pressure in the cavern plays an essential role in improving the system performance and increase the power generation during the expansion mode. The proposed system is suitable for remote areas to increase the energy production, reduce the use of fossil fuels and helpful in the power system economics and design.

Compressed Air Energy Storage Models for Energy Arbitrage and Ancillary Services: Comparison Using Mixed Integer Programming Optimization with Market Data from the Irish Power System

AbstractA mixed integer linear programming (MIP) model is developed to simulate the dynamic performance of compressed air energy storage (CAES) systems in electricity grids composed of thermoelectric and wind energy generators. The model is termed thermo‐economic (TE) as it uses power curves from CAES manufacturers to simulate the effect of cavern pressure on the operation limits of the compressor and the expander of CAES plants. Here, the TE model and the fixed efficiency (FE) model are tested in a study of the economic potential of CAES for arbitrage and ancillary services in the Irish power system. The two models are compared by simulating the technical and economic performance of CAES under deregulated market conditions. Data from the Irish power system are used and both models are applied to various system specifications and market scenarios, while optimizing the operation of CAES for provision of energy arbitrage and ancillary services. The results show that the TE model returns 15 % to 30 % less profits than the FE one, thus demonstrating that FE models overestimate CAES profitability. This study shows that arbitrage using CAES may not be profitable with current prices in Ireland. However, CAES operation would become profitable if financial mechanisms that capture the important system‐wide benefits of CAES are put in place.

Thermodynamic analysis of a compressed air energy storage system through advanced exergetic analysis

Compressed air energy storage (CAES) is an economic, large-scale energy storage technology, but its further applications are limited by thermodynamic inefficiency. Although high-exergy destruction components can be highlighted through exergy analysis, the interactions among components and the true potential for the improvement of CAES are not obvious. In this study, an advanced exergy analysis was applied to the CAES system. The exergy destruction within each system component was split into four parts, namely, endogenous, exogenous, avoidable, and unavoidable. The thermodynamic properties of CAES were discussed in detail by combining the four parts. Results indicate that the unavoidable part of exergy destruction within the components of the system is larger than the avoidable part. The most important components based on the avoidable exergy destruction are combustion chambers, intercoolers, and aftercoolers. Exergy destruction can be significantly reduced by improving the main component efficiencies. More than half of the avoidable exergy destruction is exogenous, which indicates that interactions among components have a considerable impact on the CAES performance.

Operating compressed‐air energy storage as dynamic reactive compensator for stabilising wind farms under grid fault conditions

Compressed-air energy storage (CAES) is considered a promising energy storage system for many grid applications, including managing renewable variability and grid capacity concerns. However, compared with conventional generation such as coal or hydro, the cost of storage power of CAES is still high, which impedes its deployment. Therefore a standing question is how to operate CAES in the most efficient and economical fashion, that is, to exploit the system functions for maximum-possible benefit. This study investigates the CAES dynamic reactive capability used to stabilise wind farms under grid fault conditions. Two considered operation modes are motor mode with leading power factor and synchronous condenser mode. Analysis with a 60-MW wind farm and two types of popular wind turbines, namely stall-regulated and doubly fed induction-generator-based WTs, shows that the CAES performance is comparable or better than that of an static var compensator in most situations investigated. Therefore the reactive-power-supply function should be considered in CAES design and operation to increase the system efficiency and value.

Economic Modeling of Compressed Air Energy Storage

Due to the variable nature of wind resources, the increasing penetration level of wind power will have a significant impact on the operation and planning of the electric power system. Energy storage systems are considered an effective way to compensate for the variability of wind generation. This paper presents a detailed production cost simulation model to evaluate the economic value of compressed air energy storage (CAES) in systems with large-scale wind power generation. The co-optimization of energy and ancillary services markets is implemented in order to analyze the impacts of CAES, not only on energy supply, but also on system operating reserves. Both hourly and 5-minute simulations are considered to capture the economic performance of CAES in the day-ahead (DA) and real-time (RT) markets. The generalized network flow formulation is used to model the characteristics of CAES in detail. The proposed model is applied on a modified IEEE 24-bus reliability test system. The numerical example shows that besides the economic benefits gained through energy arbitrage in the DA market, CAES can also generate significant profits by providing reserves, compensating for wind forecast errors and intra-hour fluctuation, and participating in the RT market.

Characterizing Excavation Damaged Zone and Stability of Pressurized Lined Rock Caverns for Underground Compressed Air Energy Storage

In this paper, we investigate the influence of the excavation damaged zone (EDZ) on the geomechanical performance of compressed air energy storage (CAES) in lined rock caverns. We conducted a detailed characterization of the EDZ in rock caverns that have been excavated for a Korean pilot test program on CAES in (concrete) lined rock caverns at shallow depth. The EDZ was characterized by measurements of P- and S-wave velocities and permeability across the EDZ and into undisturbed host rock. Moreover, we constructed an in situ concrete lining model and conducted permeability measurements in boreholes penetrating the concrete, through the EDZ and into the undisturbed host rock. Using the site-specific conditions and the results of the EDZ characterization, we carried out a model simulation to investigate the influence of the EDZ on the CAES performance, in particular related to geomechanical responses and stability. We used a modeling approach including coupled thermodynamic multiphase flow and geomechanics, which was proven to be useful in previous generic CAES studies. Our modeling results showed that the potential for inducing tensile fractures and air leakage through the concrete lining could be substantially reduced if the EDZ around the cavern could be minimized. Moreover, the results showed that the most favorable design for reducing the potential for tensile failure in the lining would be a relatively compliant concrete lining with a tight inner seal, and a relatively stiff (uncompliant) host rock with a minimized EDZ. Because EDZ compliance depends on its compressibility (or modulus) and thickness, care should be taken during drill and blast operations to minimize the damage to the cavern walls.

Coupling PV and CAES power plants to transform intermittent PV electricity into a dispatchable electricity source

AbstractThis study investigates the transformation of photovoltaic (PV) electricity production from an intermittent into a dispatchable source of electricity by coupling PV plants to compressed air energy storage (CAES) gas turbine power plants. Based on historical solar irradiation data for the United States' south western states and actual PV and CAES performance data, we show that the large‐scale adoption of coupled PV–CAES power plants will likely enable peak electricity generation in 2020 at costs equal to or lower than those from natural gas power plants with or without carbon capture and storage systems. Our findings also suggest that given the societal value of reducing carbon dioxide and the sensitivity of conventional generation to rising fossil fuel prices, this competitive crossover point may occur much sooner. Copyright © 2008 John Wiley & Sons, Ltd.

Assessment of Market Potential of Compressed Air Energy Storage Systems

An assessment of the potential market for compressed air energy storage (CAES) systems in the United States is developed based on projections of CAES installations in areas of the country where CAES sales are most likely to occur before the year 2000. These projections are made using the utility storage commercialization model developed for the Electric Power Research Institute. Because the market potential for CAES depends critically on CAES's performance and economics relative to competitive technologies, the model is used to project installations of other central-station storage technologies as well. Extensive sensitivity analyses are conducted to determine the variables having the largest impact on the potential market for CAES. The market projections indicate that if the utility operating environment improves, there will be a significant market potential for CAES systems.