Adiabatic compressed air energy storage technology

Graphical AbstractView Large Image Figure ViewerDownload Hi-res image Download (PPT)For decades, technical literature has appraised adiabatic compressed air energy storage (ACAES) as a potential long-duration solution. However, it not reached the expected performance indicators and widespread implementation. Here, we reflect on design requirements specific challenges for each ACAES component. We use evidence from recent numerical, theoretical, experimental studies to define technology-readiness level (TRL). Lastly, discuss promising new directions future technology development. For Adiabatic is frequently suggested alternative bulk electricity storage, alongside more established technologies such pumped hydroelectric and, recently, high-capacity batteries, but yet no viable plant exists. At first sight, this appears surprising, given that consistently refers its solution fact two diabatic (DCAES) plants exist at utility scale (Huntorf, Germany Macintosh Alabama, USA), with over 80 years of combined operation. In article, aspects main components constitute (CAES) system, fundamental differences between how they operate in contexts, need be overcome become option future. These are grounded thermodynamics consistent pilot plants, where information been made available. Finally, suggest adopting whole systems philosophy would maximize chances successful demonstration worthwhile areas research both simulation studies. Any CAES system charged by using drive compressors, resulting heat. DCAES, heat extracted exchangers (HEX) dissipated (being low grade therefore value), whereas pressurized stored dedicated pressure vessel, herein referred high-pressure (HP) store. Crucially, there transfer charging discharging processes. To discharge released HP store heated combustion chamber natural gas finally expanded through turbines generating electricity. This process illustrated lower section 1. The conceptually similar DCAES (Figure 1, upper section) different management. ACAES, compression used reheat prior expansion, removing additional fuel necessitating thermal (TES). might some degree, dramatically changes nearly all common constituent components. Equation 1 gives isentropic work, ?W, which required compress an mass ?m inlet temperature, pi Ti, respectively, outlet po single stage:?W?m={ho?hicpTi[(popi)??1??1]perfectgasapproximation.(Equation 1) ho?hi denotes change enthalpy inlet-to-outlet state, cp capacity constant pressure, dh=cpdT perfect approximation (simplifying ideal model assuming heats), ? ratio heats (??1.4 dry standard conditions). reversible, accordingly, also work available expansion (available opposite sign). Studying several apparent. First, unless controlled constant, or significant overcompression, final will variable. increasing during leads variable temperatures, effect mirrored discharging. Second, processes strictly coupled because without supplemental input, full can only recovered when temperature same (i.e., Tie=Toc=(popi)??1?). Therefore, maximum efficiency, must reverse path TES should preserve temperatures. true case external source independently supply specified decoupling Third, minimized staging cooling back ambient stages (minimum attained equal stages). limit intercooling N stages, becomes ?W?m=?n=1NcpTi[(popi)??1N??1], approaches isothermal ?W?m=RTilog(popi) N??. observations lead crucial systems, highlighting conceptual similarity simply swapping highly misleading. reality, switch means turbomachinery completely reengineered. As result second third observations, greater number interstage fewer high example, Huntorf 20 axial (pressure 1.05) 6 radial 1.8), accomplished just stages.1Jafarizadeh H. Soltani M. Nathwani J. Assessment under enhanced modifications.Energy Convers. Manag. 2020; 209: 112662https://doi.org/10.1016/j.enconman.2020.112662Crossref Scopus (24) Google Scholar Conversely, charge-discharge coupling turnaround operational principle—the turbine lowered compressor temperatures increased. go against general trends compressors losses tend increase higher management challenging, turbines, yield power extraction (gas above 1,200K now common). Furthermore, sliding another limiting factor efficiency even idealized components.2Barbour E.R. Pottie D.L. Eames P. Why option?.iScience. 2021; 24: 102440https://doi.org/10.1016/j.isci.2021.102440Abstract Full Text PDF PubMed (5) Although issue less affected due larger allowing smaller individual variation, fixed highlights challenge researchers face designing ACAES. adiabatic, high-pressure-ratio required. predicted long-duration, high-power role perhaps favors machines, aerodynamic limits make simultaneous high-mass-flow machines very challenging design, typically requiring transonic flow provide necessary compression. It noted that, although manufacturers do display models able reach ratios rates, does mean “on-stock” suitable Rather, indicates family adapted, optimized, designed specifically application. learn development efficient (LTT) other applications, particularly geothermal production, (PTES), low-grade heat-to-power organic Rankine cycle (ORC) systems. present time, LTT limited. Adapting steam applications possibility proposed literature, these generally levels significantly than their equivalent.3Giovannelli A. Tamasi L. Salvini C. Performance analysis industrial expander Compressed Air Energy Storage systems.Energy Rep. 6: 341-346https://doi.org/10.1016/j.egyr.2019.08.066Crossref (6) compression-expansion major HEX. 2 defines HEX effectiveness, ?—the actual rate Q? theoretical Q?MAX—as generalized balance (neglecting environment).?=Q?Q?MAX=Ch(Th,i?Th,o)CMIN(Th,i?Tc,i)=Cc(Tc,o?Tc,i)CMIN(Th,i?Tc,i)(Equation 2) CMIN=MIN[m?ccc,m?hch] minimum flowrate (the product fluid flow), m?c m?h rates cold hot fluids, cc ch respective capacities. Tc,i Th,i Tc,o Th,o clear achieve close balanced m?ccc=m?hch) effectiveness. classical methodologies, high-HEX effectiveness ?>0.9 achieved severely unbalanced conditions (CMIN/CMAX?1). instance, aftercooler utilizing water coolant ?=0.9 moderate surface area; however, normal around five times condition, leading small (20K, comparison 100K air). imbalance allows equipment compactness, typical core volumes ?0.5m3, reducing pumping saving space. contrast, if 95% condition imposed, volume 6-fold still capable reaching 0.75–0.8. case, reversibility superior.4Kays W.M. London A.L. Compact Heat Exchangers (Third edition). Krieger Publishing Company, 1998Google (unbalanced) example plant, requires approach. primary finding appropriate trade-off reversibility, cost. stores exergy (1) (2) TES. former, capacity. criteria thermomechanical integrity tightness lifetime shared conventional DCAES. well documented aboveground underground storage. behavior properly integrated into (e.g., Wang et al.,5Wang S. Zhang X. Yang Zhou Y. Experimental study storage.Energy. 2016; 103: 182-191https://doi.org/10.1016/j.energy.2016.02.125Crossref (99) reports importance Barbour al.2Barbour associated fluctuation analytically addressed). Recent outlined thermodynamic benefits isobaric storage; variable-volume adds complexity explore trade-off. critical part seamlessly Over half generated currently operation combustion, input. maintain after until reintroduced expansion. Thermal huge range domestic vast parallel field. Specific relate (and potentially pressures) involved large-capacity requirements, simultaneously mechanically strong, efficient, cheap. Moreover, (due isochoric storage) imposes avoiding internal mixing consequent losses. Aspects discussed sections summarized 2. Numerous examples found i.e., round trip 50%–75%.6Mucci Bischi Briola Baccioli Small-scale storage: control strategy via dynamic modelling.Energy 243: 114358https://doi.org/10.1016/j.enconman.2021.114358Crossref Scholar,7Chen Arabkoohsar Zhu T. Nielsen M.P. Development micro-compressed based experiments.Energy. 197 (2020.117152)https://doi.org/10.1016/j.energy.2020.117152Crossref (28) Within these, subcomponents exchangers, turbines) “black-box” models, inputs considering component detailing. approach useful describing operating principles, omits important limitations and/or challenges. unrealistic predictions indicators. Papers specify exist;8Sciacovelli Li Chen Wu Garvey Ding Dynamic (A-CAES) – link performance.Appl. Energy. 2017; 185: 16-28https://doi.org/10.1016/j.apenergy.2016.10.058Crossref (139) rather custom-designed paper,2Barbour derive providing reference specifying target this. highlighted illustrates assumptions regarding many papers misleading, unique requirements. consider optimized remains lack publications covering heavily consideration across system. likely reason disparity simulated measured current time. Most limited studying components, conducting analysis. TICC-500 rare published, comprehensive study. round-trip (RTE) 22.6%, 41%.5Wang decrease was attributed transient TES, anticipated Nevertheless, provides strong foundation full-system prototypes. 2016, ALACAES published results located Switzerland, reporting estimated RTE 63%–74%.9Geissbühler Becattini V. Zanganeh G. Zavattoni Barbato Haselbacher Steinfeld Pilot-scale advanced Part 1: description tests sensible thermal-energy storage.J. Storage. 2018; 17: 129-139https://doi.org/10.1016/j.est.2018.02.004Crossref (86) neglecting leakages, simulating (with 85%) introducing 90% turbine, unsuitable included. Disregarding estimate, aim investigate cavern packed-bed rock-filled Both performed satisfactorily reduced pressures. majority academic have undertaken small-scale pressures, yielding difficult scale-up. misleading metrics often presented, peak-instantaneous (defined within narrow range) total consumed energy). A proportion occurred commercial settings, accompanied optimistic, opaque, claims. part-EU-funded project ADELE, originally intended produce world’s large-scale claimed proven 70% technically feasible,10Zunft al.Electricity BMWi-project Adele-ING.in: International ETG Congress. 2017: 1-5Google ever built details were published. Canadian company Hydrostor operates recently announced received substantive grants R&D plants. available, presented Ebrahimi al.11Ebrahimi Carriveau R. Ting D.S.-K. McGillis Conventional grid connected underwater facility.Appl. 2019; 242: 1198-1208https://doi.org/10.1016/j.apenergy.2019.03.135Crossref (34) suggests (which proof concept) efficiency. Notably, employs mitigate Other well-funded ventures previously optimistic claims, Lightsail SustainX, failed any since discontinued. Two notable mentioned extensive review al.,12Wang Lu K. Ma Dooner Miao D. Overview Technology Development.Energies. 10: 991https://doi.org/10.3390/en10070991Crossref (125) claiming efficiencies 55% 60% 1.5 10 MW respectively; supporting references provided defunct. publications, projects, milestones 3. Despite (TRL) high, (we TRL 8 adoption), low. experiment5Wang sole prototype mainstream literature. Furthermore , developing failed, despite funding, leaving little way documentation lessons learned. Hence, 3–4 appropriate. puts PTES, unproven option, arguably below liquid (LAES), demonstrator facility UK University Birmingham, UK. surprising simpler layout PTES LAES DCAES; discussed, shown 3A, announcements could improve ACAES; dependent success dissemination 3B shows time writing. established, level. avenues explore. particular, adoption whole-system approach, relating feasible designs black-box generic models) hugely valuable. then accurately achievable subsequently viability. terms development, higher-outlet-temperature lower-inlet-temperature vital. includes description, analytical prediction, CFD, scales. Isobaric interesting avenue pressure. focus real conditions. Full-plant prototypes settings advance state knowledge surrounding symbiotic concepts, reversible challenge. Overall, clean cost-effective method future, strongly recommend funding bodies support further private sector better raising capital, short horizons investors want return investment makes option. failures thus far yielded learned contributed uncertainty technology. commitment transparent most worthwhile, unverifiable claims influence awards. articles blindly repeat scrutiny. If fulfill protagonist market, tackle key outstanding been, so far, mainly overlooked. D.L.P. supported scholarship Loughborough University. authors declare competing interests.