Liquid Air Energy Storage Research Articles

Economic feasibility assessment of a solar aided liquid air energy storage system with different operation strategies

In response to severe environmental problems, the proportion of new energy consumption worldwide is on an unprecedented upward trend, bringing energy storage technologies into focus. Among various energy storage systems, the solar aided liquid air energy storage (SALAES) system shows great prospects for development due to its cleanliness and high efficiency. This paper develops a basic operation strategy based on the idea of peak and valley reduction, considering the temporal fluctuation characteristics of solar energy. Further, operation modes for replacing the oil-air heat exchangers are proposed and an optimized strategy is developed accordingly. Real weather data of Beijing are used to estimate the annual power output of each system, and economic analyses are carried out on this basis using the levelized cost of storage (LCOS) method. The results show that the introduction of solar energy can reduce the LCOS of the liquid air energy storage system by 4.1 %–13.67 % and the proposed optimized operation strategy can increase the annual power output, resulting in a 0.2 %–0.4 % reduction in LCOS compared to the basic operation strategy. In addition, the impact of the molten salt tank capacity on the investment and return of the SALAES system is investigated. The optimal molten salt tank capacity obtained in this paper is 5 h, with the lowest LCOS of 0.1477 $/kWh and the shortest dynamic payback period of 10.29 years when operating with the optimized strategy.

Comprehensive Review of Liquid Air Energy Storage (LAES) Technologies

In recent years, liquid air energy storage (LAES) has gained prominence as an alternative to existing large-scale electrical energy storage solutions such as compressed air (CAES) and pumped hydro energy storage (PHES), especially in the context of medium-to-long-term storage. LAES offers a high volumetric energy density, surpassing the geographical constraints that hinder current mature energy storage technologies. The basic principle of LAES involves liquefying and storing air to be utilized later for electricity generation. Although the liquefaction of air has been studied for many years, the concept of using LAES “cryogenics” as an energy storage method was initially proposed in 1977 and has recently gained renewed attention. With the growing need for alternative energy storage methods, researchers have increasingly explored the potential of cryogenic media, leading to the development of the first LAES pilot plant and a growing body of research on LAES systems. However, one notable drawback of LAES is its relatively low round-trip efficiency, estimated to be around 50–60% for large-scale systems. However, due to its thermo-mechanical nature, LAES offers versatility and can be easily integrated with other thermal energy systems or energy sources across a wide range of applications. Most of the existing literature on LAES focuses on thermodynamic and economic analyses, examining various LAES configurations, and there is a clear lack of experimental studies in this field. This paper aims to conduct a comprehensive review of LAES technology, with a focus on the performance enhancement of these systems. Future perspectives indicate that hybrid LAES solutions, incorporating efficient waste energy recovery sections, hold the most promise for enhancing the tech-no-economic performance of standalone LAES systems.

Tech-economic analysis of liquid air energy storage - A promising role for carbon neutrality in China

Liquid air energy storage (LAES), a green novel large-scale energy storage technology, is getting popular under the promotion of carbon neutrality in China. However, the low round trip efficiency of LAES (~50 %) has curtailed its commercialization prospects. Limited research is conducted about the economic analysis, especially on the end-user side, as some national electricity policies may be friendly to the development of LAES. Therefore, a practical LAES system with 100 MW peak electricity output and a 501 MW heating supply is proposed. A typical example system built in Huitong District, Hebei Province, is given. The simple payback period and dynamic payback period are respectively 10.4 years and 6.5 years, while the levelized cost of storage is 0.11 $/kWh and the levelized cost of energy is 0.32 $/kWh. The subsequent economic analyses show that the payback period of the LAES system at the end-user side can be reduced by half compared to the LAES system at the power grid dispatching side, owing to its diversified incomes. There is an optimal peak regulation depth of 20 % in the thermal/renewable power plants integrated with LAES under the effects of the national electricity price policies. Finally, the potential carbon-emission economy of LAES should be taken seriously, particularly in the likely event that the carbon trading market is established. Among the four typical provinces in China, Hubei Province stands out with possible earnings of 0.07–0.074 $M/year, attributed to the sound carbon-emission basis and policies. Overall, the study provides a profound understanding of the application forms of LAES with the assistance of Chinese government policies, which will be vital for the development of energy storage technologies in the future.

Thermodynamic and Economic Analysis of a Liquid Air Energy Storage System with Carbon Capture and Storage for Gas Power Plants

Liquid air energy storage (LAES) technology is helpful for large-scale electrical energy storage (EES), but faces the challenge of insufficient peak power output. To address this issue, this study proposed an efficient and green system integrating LAES, a natural gas power plant (NGPP), and carbon capture. The research explores whether the integration design is theoretically feasible for future adoption in operating the LAES system and NGPP. The effect of the charging pressure, the number of air expansion stages, and electricity prices on the overall thermodynamic and economic characteristics are investigated. The round-trip efficiency and the exergy round-trip efficiency of the proposed system are 47.72% and 69.74%, respectively. The calculations show that the minimum dynamic payback period for such a project is 3.72 years, and the lowest levelized cost of electricity is 0.0802 USD·kWh−1. This work provides a reference for peak-shaving power stations with energy storage and carbon capture.

Amorphous carbon nanosheets suitable for deep eutectic solvent electrolyte toward cryogenic energy storage

The emerging deep eutectic solvent (DES) electrolyte has great potential in realizing commercial-scale application of electric double-layer capacitors (EDLCs) served in low temperature environment. That goal, however, rests with how to design the interface structure of electrode materials for well-matching with DES electrolyte. Herein, porous carbon nanosheets (PCNs) were obtained from coal tar pitch through Friedel–Crafts acylation reaction and melting salt intercalation process. The morphology, specific surface area and porosity of porous carbon nanosheets were regulated by tailoring the abundance of the dangling-bonds grafted on the CTP molecules. Profiting from the large specific surface area, suitable pore structure and good two-dimensional structure to provide more active sites and enhance ion transport capacity, the PCNs-0.10 delivers a maximal specific capacitance of 504F g−1 at 0.1 A g−1, which is overmatch than most of previously reported for other carbon materials. As-assembled symmetrical EDLCs using K+ DES electrolyte, can be assembled to work at −40 °C to 75 °C and exhibit satisfactory energy density. The strategy proposed here has opened a new way for exploring the large-scale preparation of electrode materials suitable for ultra-low temperature capacitors.

Tapping the energy and exergy benefits of channeling liquid air energy system in the hydrogen liquefaction process

Hydrogen's low volumetric energy density challenges its role as an energy vector, especially from bulk storage and transportation viewpoint. Similar to natural gas, hydrogen liquefaction is considered the solution and way forward. The energy-intensive process typically uses liquid nitrogen as a refrigerant in the precooling cycle; however, alternative candidates have also been studied. Liquid air, which has already drawn attention as a standalone cryogenic energy-storage system, can also be a potential candidate. The discharge half-cycle of a liquid-air energy storage system is integrated as the refrigerant stream in the precooling section of the hydrogen liquefaction process. The studied scenario is part of a larger integral scheme involving multiple processes. Aspen HYSYS® v12.1 was used for the design and performance analysis of this unique concept. A process-knowledge-inspired approach was employed to optimize the design variables and realize the maximum potential benefits of the proposed integration. As a result, the total refrigerant requirement was reduced by approximately 46 % compared with the base process. Furthermore, the flexibility brought about by using equilibrium reactors helped optimize the cycle temperatures and pressures. Consequently, 42.1 % (7.88 kWh/kgLH2) less energy was consumed in the liquefaction process. The high exergy efficiency of 84.29 % indicated excellent integration and optimization. Cryogenic heat exchangers were identified as the primary sources of exergy destruction, and the coefficient of performance of the integrated process was 0.155. The concept presented and the approach adopted in this study are expected to have far-reaching outcomes and benefit the hydrogen energy network and hydrogen economy perspectives.

Conceptual review and optimization of liquid air energy storage system configurations for large scale energy storage

Among energy storage systems, Liquid Air Energy Storage (LAES) is attractive because of high energy density, ease of being scaled up, absence of geographical constraints, mature technology and use of safe materials/working fluids. This work presents a critical review of LAES system configurations in the literature to identify the criteria behind their conceptual development. The goal is achieved following the HEATSEP methodology, which allowed identifying a common thread in the evolution of all LAES configurations in the literature based on very few layouts, named “basic configurations”. The optimization of these few layouts, taking into account all possible internal heat transfers, provides a unique and comprehensive overview of existing configurations in spite of their seemingly great complexity. This picture clearly indicates the link between topology and performance improvement and provides insight into the limits of the maximum possible performance gain over the existing literature. The optimal results show that the margin for improvement is quite narrow. In the case of a complete thermal integration between charge and discharge phases with the addition of Organic Rankine Cycle system a gain from 61.9 % to 64.3 % is obtained over the best performing configuration in the literature.

Rechargeable Potassium-Ion Full Cells Operating at -40 °C.

Potassium-ion batteries (PIBs) are promising for cryogenic energy storage. However, current researches on low-temperature PIBs are limited to half cells utilizing potassium metal as an anode, and realizing rechargeable full cells is challenged by lacking viable anode materials and compatible electrolytes. Herein, a hard carbon (HC)-based low-temperature potassium-ion full cell is successfully fabricated for the first time. Experimental evidence and theoretical analysis revealed that potassium storage behaviors of HC anodes in the matched low-temperature electrolyte involve defect adsorption, interlayer co-intercalation, and micropore filling. Notably, these unique potassiation processes exhibited low interfacial resistances and small reaction activation energies, enabling an excellent cycling performance of HC with a capacity of 172 mAh g-1 at -40 °C (68% of its room-temperature capacity). Consequently, the HC-based full cells demonstrated impressive rechargeability and high energy density above 100 Wh kg-1cathode at -40 °C, representing a significant advancement in the development of PIBs.

Rechargeable Potassium‐Ion Full Cells Operating at −40 °C

AbstractPotassium‐ion batteries (PIBs) are promising for cryogenic energy storage. However, current researches on low‐temperature PIBs are limited to half cells utilizing potassium metal as an anode, and realizing rechargeable full cells is challenged by lacking viable anode materials and compatible electrolytes. Herein, a hard carbon (HC)‐based low‐temperature potassium‐ion full cell is successfully fabricated for the first time. Experimental evidence and theoretical analysis revealed that potassium storage behaviors of HC anodes in the matched low‐temperature electrolyte involve defect adsorption, interlayer co‐intercalation, and nanopore filling. Notably, these unique potassiation processes exhibited low interfacial resistances and small reaction activation energies, enabling an excellent cycling performance of HC with a capacity of 175 mAh g−1 at −40 °C (68 % of its room‐temperature capacity). Consequently, the HC‐based full cells demonstrated impressive rechargeability and high energy density above 100 Wh kg−1cathode at −40 °C, representing a significant advancement in the development of PIBs.

Design and thermodynamic analysis of an advanced liquid air energy storage system coupled with LNG cold energy, ORCs and natural resources

Design and thermodynamic analysis of an advanced liquid air energy storage system coupled with LNG cold energy, ORCs and natural resources

Liquid CO2 and Liquid Air Energy Storage Systems: A Thermodynamic Analysis

Energy storage is a key factor to confer a technological foundation to the concept of energy transition from fossil fuels to renewables. Their solar dependency (direct radiation, wind, biomass, hydro, etc. …) makes storage a requirement to match the supply and demand, with fulfillment being another key factor. Recently, the most attention is directed toward the direct electrical storage inside batteries, probably driven by interest in the transportation sector, which today is the main focus in the transition path. On the contrary, for the generation of electrical energy and, more generally, for industrial sectors whose CO2 emissions are defined as hard-to-abate, electrical storage is not a feasible answer to many political and non-technological concerns. Therefore, other storage methods must be considered to address excess electricity, the most characteristics of which being both the capacity and rate of charging/delivering. Among the efforts under consideration, the liquid storage of gases at ambient conditions is certainly an interesting option. This is the case with air and CO2. The paper focused on the storage of CO2 in liquid form, comparing its performance with those of air liquefaction, which well-studied in the literature. The paper proposed a novel plant layout design for a liquid CO2 energy storage system that can improve the round-trip efficiency by up to 57%. The system was also compared to a liquid air energy storage unit considering a state-of-the-art level of technology for components, showing better efficiency but lower energy density. Finally, a sensitivity analysis was used to discuss the most relevant variables for a plant design. Particular focus was devoted to the discharging time of the plant, one of the most relevant variables that matches the energy demand.

A novel liquid air energy storage system integrated with a cascaded latent heat cold thermal energy storage

Liquid air energy storage system (LAES) is a promising Carnot battery's configuration that includes thermal energy storage systems to thermally connect the charge and discharge phases. Among them, the high grade cold storage (HGCS) is of paramount importance due to the waste cold recovery of the liquid air regasification process. As of now, most of the literature studies on LAES designed to store the cryogenic energy using sensible heat material and only few works (including one recently carried out by the authors) proposed the implementation of phase change materials (PCMs) as alternative promising solution. This paper goes a step further numerically investigating a novel configuration of the HGCS system utilizing a cascade of multiple PCMs in place of the single PCM HGCS. By enhancing the thermal buffer effect typical of PCM media, the cascaded HGCS augments both the capacity ratio of the charge phase (0.87 vs 0.81) and the utilization factor of the discharge phase (0.87% vs 0.80%). As a result, the novel LAES system based on cascaded PCMs is capable to achieve a liquefaction specific consumption of 0.27 kWhe/kgLA, increasing thus the liquefaction performance of the single PCM HGCS by 6%.

Self-recuperative liquid air energy storage system: A new sustainable approach for uninterrupted power supply

Liquid air energy storage (LAES) system is an emerging but promising candidate solution to the intermittency and weather/climate dependability issues of renewable energy. It is also envisioned as an energy vector for its multi-faceted potential applications, especially in the energy supply chain systems, and its ability to satisfy off-terrain demands. During low energy demand, the air is liquefied and later regasified to generate electricity when needed. However, the low round-trip efficiency of the conventional approaches (∼50%) is a challenge. The present study proposes a novel self-recuperative process whereby stored liquid air is used as a refrigerant instead of external mechanisms. Four slightly modifying configurations have been studied; the best case recuperates with the cold box and the compression heat during the discharging half cycle before power recovery. The case studies are simulated using Aspen HYSYS®. This excellent integration results in a round-trip efficiency of 75.8% and a specific energy consumption of 0.071 kWh/kgLA. The proposed process consumes 39.8 MW power, 58% less than the base case, resulting in 0.10 $/ton of levelized cost (production). The scheme opens up multiple pathways for liquid air, from further integration opportunities to its service in a continuous power generation mode as a transport medium and energy source in remote/off-grid locations. However, a dynamic and control strategy study should be conducted.

Liquid air energy storage system based on fluidized bed heat transfer

Liquid air energy storage (LAES) is a large-scale energy storage technology that has gained wide popularity due to its ability to integrate renewable energy into the power grid. Efficient cold/heat energy storage, which currently mainly includes solid-phase packed beds and liquid-phase fluids, is essential for the LAES system. However, the current heat/cold energy storage methods have limitations, such as the risk of flammability and explosion, the dynamic effect of the thermocline, and expensive investment. To address these limitations, a novel LAES based on fluidized bed heat transfer (FB-LAES) is proposed, and quartz sand is adopted as the heat/cold energy storage material. A thermodynamic model is developed, and the effects of heat exchanger design conditions and fluidization parameters on system performance are investigated, which indicates that the lower air-side/particle-side pressure drop and higher particle transport coefficient (PTC) favor the efficiency improvement of the FB-LAES system. The comparison demonstrates that the round-trip efficiency (RTE) of the FB-LAES system can reach 58.76% without stringent design conditions, while the RTE of the LAES system with traditional solid-phase (packed bed) and liquid-phase (methanol and propane) cold energy storage are 48.76% and 57.46%, respectively.

Multi-criteria evaluation and optimization of a novel thermodynamic cycle based on a wind farm, Kalina cycle and storage system: An effort to improve efficiency and sustainability

Although a liquid air energy storage system (LAESS) as a cutting-edge system can provide higher energy density, no geographical limitation and relatively low overall cost compared to similar technologies, low round-trip efficiency and immaturity of the technology are its main drawbacks. A new energy process based on a wind farm (WF), a thermodynamic process based on Kalina cycle, and a storage system based on LAESS technology is developed. Kalina cycle is employed to recover waste heat. A part of the thermal energy of the compression process is utilized to produce domestic hot water (DHW). The performance of the integrated process is investigated from the thermo-economic and optimization points of view. Additionally, the conceptual design of the wind farm has been developed for a specific region and according to three different wind turbines. The obtained results indicated that the electric round-trip efficiency and total cost rate of the system can be optimized by 6.7% and 8.4%, respectively, compared to the non-optimization state. It was also found that the payback time of the project under case II (WF+ KC-LAES) based on Enercon wind turbines can be lower by almost 2.34 and 3.43 years, respectively, compared to that Vestas and Windflow wind turbine.

Simulation and analysis of a peak regulation gas power plant with advanced energy storage and cryogenic CO2 capture

Flexible gas power plants are subject to energy storage, peak regulations, and greenhouse gas emissions. This study proposes an integrated power generation system that combines liquid air energy storage (LAES), liquefied natural gas (LNG) cold energy utilization, gas power systems, and CO2 capture and storage (CCS) technologies, named the LAES-LNG-CCS system. The off-peak electricity can be stored in liquid air. During the peak period, air and gas turbines generate supplementary electricity. Both LNG chemical energy and cold energy were considered: the former was used for gas power plants, and the latter was used for LAES regasification and CCS processes. Based on the thermodynamic analysis, we evaluated the effects of the recovery pressure, CCS pressure, and combustion temperature on the system power consumption and efficiency. The results demonstrated that the system recovery pressure, CCS pressure, and combustion temperature had the greatest effects on system power generation. Round-trip efficiency (RTE) was significantly affected by combustion temperature. The largest exergy loss occurred in the gas power plant. The optimal system operating ranges of the system recovery pressure, CCS pressure, and combustion temperature were 6−10 MPa, 0.53−0.8 MPa, and 1,503−1,773 K, where the RTEs and ηEx,RS reached 55%−58.98% and 74.6%−76%, respectively. The proposed system can simultaneously achieve the synergistic functions of large-scale energy storage, multilevel energy utilization, peak regulation, and carbon emission reduction. It can also be widely used in advanced distributed energy storage applications in the future.

Techno-economic assessment of an efficient liquid air energy storage with ejector refrigeration cycle for peak shaving of renewable energies

Among large-scale energy storage systems, liquid air energy storage (LAES) is one of a potential choices, storing off-peak electricity or power from renewable energy sources with high energy density in the form of liquid air in an artificial tank, not being dependent on geological attributes. However, this system suffers from low efficiency, therefore waste heat recovery and integration with other energy systems would enhance the performance of the system. In this research study, a combined cooling, heating, and power generation (CCHP) system is integrated with the LAES to not only enhance the efficiency of the LAES but also to satisfy the cooling and heating needs. Thus, the Organic Rankine cycle (ORC) coupling with the ejector refrigeration system is employed for this purpose. The energy and exergy analyses are employed considering the economic (3E analysis) performance of the introduced system to evaluate the outputs. results show that the system generates 34927 kWh of electricity, 424 kW cooling power, and 729 kW heating power in the peak time. The designed combined system is 13% more efficient in comparison to a stand-alone LAES system. About 5058 kWh exergy is destructed during discharging. Additionally, considering California as a case study the payback of 2.98 years was obtained for the designed system.

Improvement potential detection of integrated biomethane liquefaction and liquid air energy storage system

Biomethane (BM) is highly competitive bio-energy alternatives for lowering the dependency on fossil fuels globally. The form of BM that is most suitable for storage as well as shipping to far-flung areas of the world is liquefied biomethane (LBM). However, due to the significant power consumption by compressors used in BM liquefaction process (like natural gas), it is a cost- and energy-intensive operation. Additionally, because biomethane is created at atmospheric pressure, unlike ordinary natural gas, liquefaction requires more power consumption because the pressure at which BM is produced is much less than corresponding critical pressure. Therefore, an integrated system of liquid air energy storage (LAES) system discharging end and a biomethane liquefaction process is introduced that is both economical and efficient in terms of energy use. The sub-cooling and liquefaction processes of biomethane are aided by the cold-exergy of liquid air at the time of regasification mode of LAES, which eventually lowers the refrigeration cycle duty of LBM process. On the other hand, gaining the additional advantage, the expansion stage of liquid air is aided by the thermal exergy of a compressed mixed refrigerant (MR). On the basis of conventional exergy analysis, composite curves analysis, advanced exergy analysis, and sustainability index, the impacts of novel integration of LBM and LAES are estimated in this study. Conventional exergy analysis determines that 15.9 % of exergy destruction is decreased in the proposed LBM-LAES system having additional power production of 4529 kW using gas turbine. Results based on advanced exergy analysis conclude that avoidable, endogenous and exogenous portions of exergy destructions are decreased by 28.9 %, 39.9 % and 43 %, respectively; which implies the significant improvement potential. Composite curves analysis depicts that the efficiency of primary cryogenic heat exchanger is improved in the proposed integrated scheme. Additionally, the overall sustainability index is increased from 1.55 to 2.13 for LBM-LAES process.

A Novel Analysis of Energy Density Considerations and Its Impacts on the Cost of Electrical Energy Storage (EES) Plants

Geological restrictions and the low energy density of compressed air energy storage (CAES) plants constitute a technical and economic barrier to the enablement of variable and intermittent sustainable sources of energy production. Liquid air energy storage (LAES) and pumped thermal energy storage (PTES) systems offer a promising pathway for increasing the share of renewable energy in the supply mix. PTES remains under development while LAES suffers from low liquefaction unit efficiency, although it is at a higher technology readiness level (TRL) than PTES. The most significant element of large-scale EES is related to the discharge features of the power plants, especially the energy storage unit. Here, a novel multi-aspect equation, based on established codes and thermodynamic principles, is developed to quantify the required storage capacity to meet demand consistent with the design parameters and operational limitations of the system. An important conclusion of the application of the multi-aspect equation shows that liquid air storage systems instead of compressed air would reduce the space required for storage by 35 times. Finally, a cost equation was introduced as a function of the required storage volume. Calculations have demonstrated that the use of the novel cost equation, in lieu of the old one-aspect cost equation, for an LAES power plant with a production capacity of about 50 MW makes the costs of installing liquid air storage tanks against the total expenditure of the power plant about six times higher than what was reported in earlier research.

Performance improvement of air liquefaction processes for liquid air energy storage (LAES) using magnetic refrigeration system

It is essential to shift towards renewable energy for environmental concerns. Liquid air energy storage is an attractive option to store this energy in terms of energy savings, grid balancing and large-scale energy system with no geographical constraints. However, it has a low round trip efficiency, to which the energy intensity of air liquefaction is a major contributor. This study proposes novel configurations employing magnetic refrigeration pre-cooling for air liquefaction cycles (Linde-Hampson, Claude and Kapitza). The conventional and new liquefaction schemes are modeled and simulated on Aspen Hysys. The proposed schemes for the liquefaction step of the LAES process are assessed thermodynamically and economically based on specific energy consumption (SEC), exergy efficiency and levelized cost of product (LCOP). The results show that SEC for Linde-Hampson, Claude and Kapitza with AMR pre-cooling reduces by 11.20 %, 10.96 % and 7.24 %, respectively, compared with conventional air liquefaction cycles without precooling. Also, exergy efficiency for cycles with AMR pre-cooling increases by 1.03 %, 3.13 % and 2.12 %, respectively. It is found that Kapitza-AMR process gives the lowest value for LCOP of 7.62 US$/kgLAir as compared to 8.61 US$/kgLAir for the LH-AMR and 8.03 US$/kgLAir for the Claude-AMR process. A sensitivity analysis is also performed to study the effect of varying process parameters on performance of the active magnetic regenerator (AMR) pre-cooling section.