Optimizing near-adiabatic compressed air energy storage (NA-CAES) systems: Sizing and design considerations

Liu X., Zhong L., Wang J.

For the strict site requirement and the consumption of fossil fuel in compressed air energy storage system, the large-scale application of compressed air energy storage is limited. In this paper, a hot dry rock compressed air energy storage system is proposed, and the cracks of hot dry rock are used as the storage place of compressed air. Meanwhile, the thermodynamic model and wellbore model are constructed to evaluate the performance of proposed system. In the range of mass flow rate and recharge pressure of present work, the numerical results illustrate that the production temperature increases with the augment of the mass flow rate, but the increase of the recharge pressure has no obvious effect on the production temperature. Besides, the consumption of valley electricity increases with the augment of mass flow rate and the reduction of the recharge pressure. In addition, the round trip efficiency of the system fluctuates between 48.59%∼54.88%, which is much better than that of the traditional compressed air energy storage system (42%).

Zhang X., Li Y., Gao Z., Chen S., Xu Y., Chen H.

Compressed air energy storage (CAES) is an effective solution to make renewable energy controllable, and balance mismatch of renewable generation and customer load, which facilitate the penetration of renewable generations. Thus, CAES is considered as a major solution for the sustainable development to achieve carbon neutrality. Two traditional CAES plants (Huntorf, McIntosh) utilize fossil fuel to preheat compressed air when discharging, which produce emissions to environment. Advanced CAES technology which eliminates the using of fossil fuel is considered as a clean energy technology, and has been studied and developed intensively in the past decade. These advanced CAES includes adiabatic CAES (ACAES), isothermal CAES (ICAES), liquid air energy storage (LAES), supercritical CAES (SC-CAES), underwater CAES (UWCAES), and CAES coupled with other power systems. Some MW scale demonstrations of these advanced CAES technologies are constructed and operated. The CAES system has to be operated dynamically to manage the imbalance between renewable generations and electricity demand. Moreover, the compressed air is usually stored in the isochoric vessel or carven. Thus, the power output and operation pressure have to be adjusted and controlled accordingly. These technologies that adjust and regulate the air flow are reviewed and summarized, which are throttling valve control, ejector, guided vane adjustment, switching expansion reducing and some others. The characteristics and effect to the CAES system are also discussed. This paper presents a comprehensive reference for adjusting novel CAES systems to realize dynamic operation with high performance. This study helps to facilitate the integrating and planning of different types of CAES and their dynamic control strategies in energy systems for various applications.

Li R., Tao R., Yao E., Zhang H., Niu Y., Ling L., Yan A., Wang H.

Compressed air energy storage (CAES) system is a promising solution for matching the intermittent renewable energy sources and stable electricity demand of end users. However, the heat loss during the compression heat utilization is the vital aspect for thermodynamic performance improvement of CAES. Therefore, a novel hybrid CAES system consists of advanced adiabatic CAES and near isothermal CAES is proposed in this study. Compared with the traditional adiabatic compression process, the conduction of near isothermal compression process could avoid the generation of compression heat significantly under the same pressure ratio. The results show that the conduction of near isothermal compression process could enhance the thermodynamic performance of the CAES system. In addition, since the thermal energy storage (TES) is the key equipment for the proposed system to achieve convergent operation condition, the mathematical model of TES was established in this paper to investigate the thermodynamic performance of the proposed system. Furthermore, the system performance could be enhanced by taking the higher values of height of TES, outlet pressure of compressor and specific heat capacity of filling material, while lower values of diameter and thermal conductivity coefficient of filling material. Through the comprehensive thermodynamic analysis, the proposed system could achieve the highest energy efficiency of 72.47 % when the storage pressure of the air storage tank equals 11 MPa.

Piri A., Aghanajafi C., Sohani A.

As an effective solution for the increasing energy and environmental crises, application of renewable energy is growing worldwide at a rapid pace. Since the energy production by renewable energy resources changes during the time, energy storage technologies come into operation to regulate the output of such systems. This research work provides an innovative way to increase the efficiency of a renewable energy assisted system with the adiabatic compressed-air energy storage (A-CAES) by multiple Kalina recovery cycles, which have appropriate performance at the medium and low temperature levels. In the proposed system, three Kalina recovery cycles, two of which work in the charging phase and one of which works in discharging phase, are employed. A comprehensive thermodynamic analysis, including finding and comparing the sensitivity of different effective parameters on the system performance, is conducted. The results show that the power production of the system has been improved from 3776.7 kW to 3904.0 kW, which means 3.38 % increase. Moreover, the round-trip exergetic efficiency has increased by 3.12 %, i.e., from 41.7 % to 43.0 %. The corresponding value for the round-trip energy efficiency is also 3.30 %, where the values before and after optimization are 48.5 % and 50.1 %. Furthermore, the values of power production for the Kalina cycles I, II, and III (KCSI, KCSII, and KCSIII) in the optimum condition are 69.3 kW, 79.7 kW, and 118.4 kW, respectively. The gained enhancement values have proven that the proposed system can enhance the system performance significantly.

de Souza M.F., Canizares C.A., Bhattacharya K., Lorca A.

This paper presents a novel methodology based on Principal Components Analysis (PCA) and Affine Policies (AP) for self-scheduling of a price-taker Compressed Air Energy Storage (CAES) facility operating under uncertainties. The proposed PCA-AP model is developed from the facility owner's perspective, which partakes in energy, spinning, and idle reserve markets. A methodology is proposed to select the required price uncertainty intervals from actual data based on a Box Cox technique. For a more realistic representation, the detailed thermodynamic characteristics of the CAES facility are considered, taking into account as well modern CAES facilities that may charge and discharge concurrently. To validate the proposed PCA-AP model and approach, the results obtained are compared with an existing Affine Arithmetic (AA) model, which is also based on an affine approach, and Monte Carlo Simulations (MCS), which can be considered as the benchmark for comparison purposes. The input data, forecast prices and intervals of uncertainty, are taken from the Ontario-Canada electricity market for 2015-2019. From the studies presented, it can be observed that the new PCA-AP approach provides less conservative results as compared to the AA approach, and hence can be considered an adequate methodology for day-ahead operations in systems with significant sources of uncertainty.

Kosowski K., Piwowarski M., Włodarski W., Ziemiański P., Pawlak G.

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.

Sarmast S., Rouindej K., Fraser R.A., Dusseault M.B.

Correctly sizing a compressed energy storage (CAES) system by considering external power grid requirements, component limitations, and operation restrictions is essential to successfully enhancing a CAES system’s usability and effectiveness. A new method, referred to as the coverage-percentage method, is developed and applied to Ontario as a case study, to size a CAES system based on its percentage ability to capture excess energy and deliver energy during a shortage. The coverage-percentage method builds upon and improves upon the frequency-of-occurrence method proposed by Rouindej et al. (2019) by adding time dependent operation considerations (cavern pressure and temperature), and component limitations (compressor, expander, and cavern sizes). These additional considerations improve both sizing accuracy and usability understanding. One major advantage of the coverage-percentage method is that it rectifies the overestimation of the frequency-of-occurrence method with regards to the percentage of excess energy that can be stored, and stored energy that can be delivered, for a given sized expander, compressor, and cavern. For example, it is observed that a cavern size of 950 MWh for Ontario can capture and deliver 85% of excess energy, while the coverage-percentage method results reveal that a cavern of 950 MWh can actually only cover 48% of Ontario’s charging potential. These significantly differing results between the frequency-of-occurrence method and the coverage-percentage method because of the interplay of expander, compressor, and cavern sizes not considered in the frequency-of-occurrence method, but most critically because cavern damaging pressure and temperature limits are not considered in the frequency-of-occurrence method. By applying the coverage-percentage method to 2018 to 2020 Ontario electrical grid data, and to a salt cavern with pressure limits between 5 MPa and 14 MPa, it is revealed that compressors sized between 30 MW to 70 MW, expanders sized between 40 MW to 90 MW, and cavern energy capacities between 630 MWh and 770 MWh would be sufficient to capture at least 42% and 26% of charging and discharging opportunities, respectively.

Matos C.R., Silva P.P., Carneiro J.F.

Energy storage (ES) plays a key role in the energy transition to low-carbon economies due to the rising use of intermittent renewable energy in electrical grids. Among the different ES technologies, compressed air energy storage (CAES) can store tens to hundreds of MW of power capacity for long-term applications and utility-scale. The increasing need for large-scale ES has led to the rising interest and development of CAES projects. This paper presents a review of CAES facilities and projects worldwide and an overview of the ES regulatory framework and policies. It performs two benchmarking procedures: first, a benchmark of CAES worldwide, and second a benchmark of ES regulatory frameworks, policies, drivers and barriers. It tries to understand whether the development or cancellation of CAES projects globally is in any way related to the development of ES policies. This study addresses policy perspectives and specific ES regulatory framework recommendations, contributing to public policy design in the attempt to overcome the regulatory barriers to the ES sector and influencing the deployment of ES and, specifically, CAES. Removing current regulatory barriers and establishing new and broader policies are essential to provide ES and CAES technologies with the right opportunities to develop, enhance efficiency, increase operational experience, and reduce costs. • Benchmark of Compressed Air Energy Storage (CAES) projects worldwide • Overview of energy storage (ES) regulatory framework, policies, drivers, and barriers • Recommendation of measures that should be taken to remove ES and CAES barriers • CAES projects' deployment seems to be linked with developed ES policy countries. • Implementation or cancellation of CAES projects is not usually due to ES policies.

Bazdar E., Sameti M., Nasiri F., Haghighat F.

The intermittency nature of renewables adds several uncertainties to energy systems and consequently causes supply and demand mismatch. Therefore, incorporating the energy storage system (ESS) into the energy systems could be a great strategy to manage these issues and provide the energy systems with technical, economic, and environmental benefits. Among all energy storage systems, the compressed air energy storage (CAES) as mechanical energy storage has shown its unique eligibility in terms of clean storage medium, scalability, high lifetime, long discharge time, low self-discharge, high durability, and relatively low capital cost per unit of stored energy. In contrast, low roundtrip efficiency (RTE), low depth of discharge, and high response time are considered its main drawbacks. This paper presents a comprehensive review of technological developments in CAES systems, including its design criteria and emerging application potentials. Furthermore, a detailed review of the most recent research progress on CAES technology and its challenges is presented from the point of view of the different integration potential of CAES, optimal designing, and scheduling with the role of CAES towards micro-grid, distribution energy network, and energy market environment. Finally, the limitations and future perspectives of CAES are described and summarized. This paper presents a comprehensive reference for integrating and planning different types of CAES in energy systems for various applications. • A review of the CAES practical applications and characteristics is carried out. • A comprehensive classification and comparison of various CAES are given. • The concept of CAES integration with energy conversion systems is introduced. • Different approaches for sizing the CAES components are presented. • CAES's optimal scheduling is discussed from the energy market, distribution network, and microgrid perspective.

Li Y., Yao F., Zhang S., Liu Y., Miao S.

Adiabatic compressed air energy storage (A-CAES) technology naturally has the ability of cogenerating cooling heating and electric power. It is a promising energy storage technology in the application of combined cooling, heating and power (CCHP) dispatch. This paper explores a new modelling method of the A-CAES for CCHP dispatch by taking the temperature dynamic behavior of the A-CAES into detailed consideration. With the help of the binary technique and piecewise approximation method, this A-CAES model is formulated based on mixed-integer linear programming (MILP), which can be easily solved. On the basis of this, an optimal day-ahead dispatch model for a CCHP microgrid containing an A-CAES is proposed. The empirical study based on a pilot plant and system data in China is carried out. The simulation results verify the effectiveness of the proposed A-CAES model. With the comparison of the results using the proposed A-CAES model and the conventional A-CAES model without considering temperature dynamic behavior, the results show that the system operation cost obtained by the proposed model can be 13.7% lower than the results obtained by the conventional A-CAES model. • A dispatch model of adiabatic compressed air energy storage for combined cooling, heating and power dispatch is proposed. • Temperature dynamic behavior is considered to make the dispatch model more realistic. • Empirical study based on pilot plant and system data in China to provide real-life experience. • The results demonstrate the importance of temperature dynamic behavior in combined cooling, heating and power dispatch.

Roos P., Haselbacher A.

We review the literature on analytical models of advanced adiabatic compressed air energy storage plants with isochoric reservoirs, with a focus on the insights that can be extracted from the models. The review indicates that models for plants with adiabatic reservoirs, adiabatic turbomachinery, and without throttling is missing from the literature. We proceed to derive such models, assuming that the plant is operating at the quasi-steady state, that air can be treated as a calorically and thermally perfect gas, and that thermal-energy storage units are free of thermal and pressure losses. The models result in closed-form expressions for key performance indicators like the plant efficiency and volumetric energy density in terms of component efficiencies and pressure ratios. The derivation of these expressions rests on approximating integrals involving simultaneous temporal variations of temperature and pressure. The approximation leads to relative errors with magnitudes smaller than 1%. The models show that the compression and expansion work, the plant efficiency, and the maximum process temperature exhibit minima. The models also show that for a given non-dimensional storage capacity and maximum reservoir pressure, the maximum efficiency of plants that minimize the maximum process temperature is approximately equal to the minimum efficiency of plants that maximize the efficiency. For a two-stage plant with a diabatic cavern and diabatic thermal-energy storage units, our analytical model predicts the volumetric energy density to within 4.76%, indicating that it is accurate enough to be used for initial plant design. • Review of analytical models of advanced adiabatic compressed air energy storage. • New models developed for adiabatic reservoirs and turbomachinery, without throttling. • Models give expressions for plant efficiency and storage capacity. • Models can be used for initial plant design by estimating reservoir volumes. • Reduced maximum process temperatures imply reduced plant efficiencies.

Sarmast S., Fraser R.A., Dusseault M.B.

Although Compressed Air Energy Storage (CAES) is not a new technology, it has not yet been widely adopted due to location restrictions and inefficiencies. Thermal energy storage improves the round-trip efficiency of CAES systems. This study sets out to investigate the cyclic thermal storage behavior of a small-scale, site-flexible, scalable, cased-wellbore compressed air energy storage (CW-CAES) system in which both heat and mechanical energy can be stored in an array of wellbores. The concept of storing high-temperature compressed air (around 200 ° C) inside cased wells is a promising approach to expanding the utility of CAES systems through site flexibility, partial adiabatic efficiency improvements over conventional non-adiabatic CAES, no need for a separate heat storage system as found in Adiabatic CAES (A-CAES) systems, and small (order 1 MW; 10 MWh) to large (order 150 MW; 600 MWh) capacity that can be achieved through the modular nature of multiple wellbores. This paper provides a detailed numerical model coupled with a semi-analytical model to assess the first year operation of PA-CW-CAES. The results reveal that the semi-analytical model yields results in excellent agreement with the numerical model. To improve thermal storage an array of boreholes is considered. Several charge/discharge cycles are used to appraise the system behavior and determine system efficiency. The simulations confirm that the modeled partial adiabatic CW-CAES has a round-trip efficiency of around 40% which is higher than the corresponding diabatic CW-CAES operating at the same conditions, and that this efficiency increases with time the more charge/discharge cycles CW-CAES experiences. • A small-scale partially-adiabatic compressed air energy storage (PA-CAES) system based on a pressurized wellbore is studied. • A cased-wellbore array is utilized as a repository to store both heat and mechanical energy. • The PA-CW-CAES performance is better than that of an equivalent diabatic CW-CAES system. • An algorithm was developed to decrease the computational costs of numerical simulations. • The surrounding rock acts as a passive low-temperature long-term underground TES.

Saleh Kandezi M., Mousavi Naeenian S.M.

• A green hybrid system based on liquid air energy storage, Kalina, and absorption cycles. • A comprehensive and systematic evaluation of the proposed hybrid concept. • Achieving the round trip energy and exergy efficiencies of 66.32% and 49.75%. • Reaching a payback period of 3.5 years and total profit of 11.45 $M. • Analyzing the system performance based on real data in California, the USA. Liquid air energy storage is a very new energy storage technology for large-scale applications with brilliant advantages over the other available grid-scale storage concepts such as higher energy density and no topographical restriction. In the present study, to assist more development of this technology, an efficient and green multi-generation system based on the liquid air energy storage, absorption cycle, and Kalina system is proposed and deeply investigated from the first and second laws of thermodynamics and economic. Moreover, a sensitivity analysis is conducted to scrutinize the effect of critical parameters on system performance. The proposed system can be efficiently used for power and cooling capacity production during peak demand periods, both of which can assist peak shaving and grid stability. Thermodynamic analysis indicates that during peak demand periods, a power of 5300 kW is generated by the air turbine during 3 h and with round trip energy and exergy efficiencies of 65.7% and 49.7%, respectively. The economic analysis shows that the investment cost of the system is around 3.68 $M and the referenced system has a payback time of 3.6 years and a total turnover of 11.3 $M can be achieved at the end of 25th year.

Ghadi M.J., Azizivahed A., Mishra D.K., Li L., Zhang J., Shafie-khah M., Catalão J.P.

While compressed air energy storage (CAES) has many applications in the field of generation and transmission power systems based on the state-of-the-art, this paper proposes the application of small-scale CAESs (SCAESs) in form of a storage aggregator in the daily operation of an active distribution system (ADS), joining the distribution system operator (DSO) for the participation in the day-ahead (DA) wholesale market. An innovative two-agent modeling approach is formulated. The first agent is responsible for aggregating SCAES units and the profit maximization of the aggregator is based on the distribution local marginal price. The DSO as the second agent receives the DA scheduling from the independent SCAES aggregator and is thus responsible for the secure operation of the ADS, utilizing solar and dispatchable distributed generation (DG) as well as purchasing power from the wholesale market. Linear programming is used for the formulation and optimization of the SCAES aggregator, while a bi-objective optimization algorithm (with the objectives of minimum operating cost as well as minimum power loss and emissions in different scenarios) is employed for DSO scheduling. The results show that the CAES aggregator can offer a considerable impact for power loss reduction, specifically, when diesel generators are not committed in the system operation (i.e., where emission has very low values between 10,000 and 12000 kg). Additionally, the CAES aggregator could reduce the operation costs of the grid in a wide range of operations, even though for the scenario in which the CAES units are not under the control of the DSO anymore and also are scheduled to maximize their own profit. Moreover, results demonstrated that CAES units can be a significant voltage control device for a distribution grid with different objectives. Finally, some conclusions are duly drawn. • This paper proposes the application of small-scale compressed air energy storage (SCAESs). • An innovative two-agent modeling approach is formulated. • Linear programming is used for the formulation and optimization of the SCAES aggregator. • Bi-objective optimization algorithm is employed for distribution system operator scheduling.

Barbour E., Pottie D.L.

Edward Barbour obtained his bachelor's degree in Physics from Oxford University and his PhD in Mechanical Engineering from the University of Edinburgh in 2013. His doctoral thesis focused on the development of ACAES and the economics of energy storage within the UK market framework. He held subsequent postdoc positions at the University of Birmingham and Massachusetts Institute of Technology. As of 2019, he is a lecturer at Loughborough University in the Centre for Renewable Energy Systems Technology (CREST), where his research is focused on thermomechanical energy storage and the future role of energy storage in the UK. Daniel L. Pottie obtained his bachelor's in Mechanical Engineering from Universidade Federal de Minas Gerais (UFMG), Brazil in 2016. In the same year, he started as a research assistant at UFMG, developing hydraulic compressed air energy storage technology. He started his MSc degree in the subject in 2018, and his thesis detailed the thermodynamic performance of a novel pumped hydraulic compressed air energy storage (PHCAES) system. He was awarded the degree in September 2019. Currently, he is a PhD candidate at Loughborough University where his research is focused on the development of competitive, efficient, and innovative adiabatic compressed air energy storage. For decades, technical literature has appraised adiabatic compressed air energy storage (ACAES) as a potential long-duration energy storage solution. However, it has not reached the expected performance indicators and widespread implementation. Here, we reflect on the design requirements and specific challenges for each ACAES component. We use evidence from recent numerical, theoretical, and experimental studies to define the technology-readiness level (TRL). Lastly, we discuss promising new directions for future technology development.

Davoodi V., Rad E.A., Haghighat F., Simonson C.J., Ting D.S.

Komba N.A., Haisong C., Liwoko B.B., Mwakipunda G.C.

Jafarizadeh H., Soltani M., El Haj Assad M., Dusseault M.B.

Zhang L., Xie M., Ye K., Li S., Chen L.

Li B., Xu H., Jiang Y., Wu C., Wang S.

Li S., Cai F., Abbas S.J., Dutta A.K., Shomurotova S., Elmasry Y.

Zhang Y., Wang H., Jin P., Cai X., Du J., Zhang W., Wang H., Li R., Cheng Z.

Zeng Z., Ma H., Yang C., Liao Y., Wang X., Cai R., Fang J.

Xu W., Zhao P., Wang J., Yang W.

Ali N.B., Basem A., Jasim D.J., Singh P.K., Sultan A.J., Rajab H., Becheikh N., Kolsi L., El-Shafay A.S.

Li Q., Liu W., Jiang L., Qin J., Wang Y., Wan J., Zhu X.

Hachemi A.T., Kamel R.M., Hashem M., Ebeed M., Saim A.

Bazdar E., Nasiri F., Haghighat F.

Ma L., Zhang X., Zhang T., Xue X., Chen X., Si Y.

Heat exchangers (HEXs) are among the key components of adiabatic compressed air energy storage (A-CAES) systems. However, the existing HEX models applied in the A-CAES systems are overly simplistic, limiting research regarding design and operational simulation. For the first time, this study incorporates a comprehensive HEX model, including calculations for geometric dimensioning, heat transfer, and pressure drop, into the A-CAES system model; in addition, a novel layered, interactive system design and operational simulation algorithms are developed. The developed models and algorithms can facilitate the design process and yield reasonable operational simulation results with only basic parameters. The design algorithm can determine all key parameters of the system and assess the effect of the HEX pressure drop and heat transfer area on the system performance. The operational simulation algorithm considers the performance of all key equipment under off-design conditions. The design exergy efficiency and daily net income of the system are 73.15 % and $26,998, respectively; however, these values decrease during operation to 72.15 % and $25,034, respectively. A comprehensive analysis of the key parameters during operation revealed that the primary causes for the degradation were the sliding pressure in the energy storage process and variations in the air storage tank parameters.

Alshammari O., Basem A., I.Hameed A., Agarwal D., Shawabkeh A., Kenjrawy H.A., Kchaou M., Jerbi H.