Review of Voltage and Frequency Grid Code Specifications for Electrical Energy Storage Applications
2. Overview of Grid Codes
2.1. Voltage Adopted by National Electricity Transmission
2.2. Normal and Critical Frequencies with Intervals Specified in Grid Codes
2.3. The Requirements of Great Britain (GB) Grid Code to Generating Units
2.4. Comprehensive Analysis of the Different Grid Code Requirements to Generating Units
2.5. Recent Updates to Grid Codes Relevant to Electrical Energy Storage (EES)
3. Electrical Energy Storage and Grid Code: Realisation and Restriction
- Cho et al.  studied a hybrid EES system including Li-ion batteries and supercapacitors, which can exploit their high energy and power capabilities to handle long-term and short-term changes, respectively. The battery can be used to cover the slow and relatively large frequency fluctuation, while the supercapacitor has been designed to weaken the fast and relatively small frequency fluctuation. The study has shown that the system can effectively regulate the frequency in meeting the power grid regulations while smoothing the net variability.
- Wojcik et al. and Li et al. [53,54] implemented technical feasibility studies of a conventional power plant (or a combined-cycle power plant, refer to Li et al.) integration with a TES facility, respectively. From the simulation study, with the proposed TES facility operation, the main generation units in power plants can run close to their design conditions with high load factors, which can improve the power plant efficiency and get flexible grid operation and in turn potentially support the Grid Code realization. The possible candidate points for TES heat extraction and release in the whole system were evaluated [53,54]. The results demonstrate that the concept is feasible. The studies can provide guides for the TES system design which can bring the minimal influence on the original power plant operation.
- Vaca built on established techniques for sizing EES to complement wind generators in providing frequency support . With the consideration of using hybrid EES, a 60 MW wind farm integration with a combination of VRB flow batteries and supercapacitors has been applied to verify the idea via the provision of Primary, Secondary and High frequency responses as defined in GB Grid Code .
- Ammar and Joós proposed a supercapacitor EES system which can be a solution to the voltage flicker resulting from the wind power integration . The study has been implemented by a 2 MW doubly fed induction generator with a 25 kV power network. The results indicated that the supercapacitor energy storage system has a superior capability to the reactive power control, which can guarantee the operation of the wind power generation unit under the Grid Code requirements .
- Guo et al.  developed a Superconducting Fault-Current Limiter-Magnetic Energy Storage (SFCL-MES) concept. The authors studied its technical benefits, i.e., enhancing the LVRT capability and smoothing the output power of the Doubly Fed Induction Generator (DFIG). With considering the LVRT Grid Code specification issued by Germany EON, the simulation study under grid fault was carried out. From the study, connecting the SFCL-MES in series with the stator can have a good LVRT performance to DFIGs.
- Serban et al.  proposed grid support strategies that can be used to alleviate grid frequency–voltage variations. In the designed system, the distributed power generators were represented by an energy storage converter, with the capacity to discharge and charge the EES element, primarily for grid support purposes. For grid support enhancement, the proposed strategy was combined with reactive power-voltage control to attempt to correct frequency and voltage deviations for the grid stabilization purpose. A single-phase 6 kVA four-quadrant EES converter was used for the simulation and experimental studies to validate the proposed grid support strategies .
- Bignucolo et al.  focused on the regulating functions required to storage units by Grid Codes to the low-voltage networks in the European area. The study shows that the dangerous operating conditions may arise in low-voltage networks when dispersed generators and storage systems are present. The interface protection systems based on passive relays can be effective in networks with a limited penetration level of dispersed generation and storage systems.
- Le and Santoso  investigated the CAES dynamic reactive capability used to stabilise wind farms under grid fault conditions (e.g., grid short-circuit events and FRT). It is desirable for wind farms to have enhanced fault-withstanding capability. Two modes were studied: motor mode with leading power factor and synchronous condenser mode . Through the study of a 60 MW wind farm and two types of wind turbines (i.e., stall-regulated and doubly fed induction-generator-based wind turbines), the authors concluded that the CAES performance is comparable to that of the Static Var Compensator (SVC) in most situations and the CAES could be more effective if utilised for the wind farm with stall-regulated wind turbines .
- A dedicated Cableway Storage System (CSS) concept was recently presented in [61,62], which has potential to provide ancillary services in the grid for supporting the Grid Code realization (e.g., voltage regulation). The principle of CSS is based on the transportation of some heavy masses, i.e., converting and storing electricity in the form of gravitational energy. Its mechanical and electrical drive models have been introduced [61,62] and a simulation study to a 1.8 MW CSS system had been implemented to analyse the system performance.
- Bignucolo et al.  studied the integration of lithium-ion battery storage systems in hydroelectric plants for supplying Primary Control Reserve required by the Grid Code specification. The simulation study of the overall system was carried out to quantitatively analyse the plant dynamic response in the case of network frequency contingencies and to study the technical benefits brought by such integration system to grid stability. A case study to the technical-economic analysis, based on data from an existing hydropower plant and the Italian context, was presented in , mainly on the investment profitability.
- Bignucolo et al.  also studied the impact of Grid Code requirements on distributed generation in Low Voltage (LV) networks with islanding detection. The effects on the interface protection performance of generators’ stabilizing functions are analysed. In the study, EES systems have been directly connected to the LV network. The impact on the anti-islanding protection effectiveness has been specifically concerned. Via the simulation study, the authors concluded that raising the distributed generation, with introducing stabilizing functions and connecting compensating units to regulate the end-users power factor, may increase the risk of failure of present loss-of-main protections .
- The adjustable speed pump storage technology has been adopted in Japan, Europe and some other countries/areas. With the solid state electrical devices using IGBT and PWM techniques, the excitation systems can utilize the rotational energy storage of the rotor in milliseconds. In this case, the rotor of an adjustable speed machine is equivalent to a rapid response flywheel. The whole pump storage system thus can alleviate the fluctuations of power and frequency. A major benefit of such technology is the tuning of the grid frequency to provide grid stability and frequency regulation . The benefits also include the system efficiency improvement and operational flexibility. The features and the practical experience by Toshiba relevant to using this technology have been introduced in .
- UltraBattery as a kind of hybrid energy storage device has been newly developed. It contains both supercapacitors and lead-acid batteries in common electrolytes. The white paper published by Smart Storage Pty Ltd. described this type of technology with the test data showing the key benefits and its applications . The innovation of UltreBattery technology is the introduction of an asymmetric supercapacitor inside a lead-acid battery for enhancing power management and reducing negative plate sulphation. The white paper claimed that the benefits of UltreBattery include long-life, high efficiency, cell voltage stability, etc. . The current and potential applications of UltreBattery technology to grid applications, such as frequency regulation, ramp-rate control and spinning reserve, were described in .
- Altair Nanotechnologies (Altairnano), based in Anderson, India, developed a lithium-titanate battery energy storage system which can provide grid ancillary services including frequency/voltage regulation . The structure of this EES system can be considered as a combination of a battery and a supercapacitor. The company claimed that: (1) the system can provide the frequency regulation on a second dispatch basis; and (2) it has an outstanding ability, i.e., three times the power capabilities compared to most types of batteries .
- Siemens has developed a new product named SVC PLUS FS using power intensive supercapacitors, which can be used for supporting both frequency and voltage grid regulation . The simulation study had been implemented in the Ireland transmission grid and the results indicate that: (1) the active power response from the device is very fast; and (2) using SVC PLUS FS, the frequency nadir in the simulation can be improved by approximately 0.1 Hz, which is similar behaviour to using a battery system for frequency stabilization but more cost-effective .
- PJM Interconnection LLC (PJM) is a part of the Eastern Interconnection in the US grid. As of 2016, there is a total of approximately 250 MW of battery storage systems installed by PJM [69,70]. The systems have been used to provide grid frequency/voltage regulation and power quality services. For instance, a Li-ion battery EES facility (32 MW, 8 MWh) has been in communalized operation since 2011, in conjunction with a 98 MW wind power generation plant in West Virginia, US [69,70]. PJM also uses flywheels for frequency regulation applications. For example, a Beacon produced flywheel facility (20 MW, 5 MWh) has been operated by PJM in Pennsylvania, US .
- In the UK, the companies Highview and Viridor were awarded funding to build a 5 MW liquid air storage system alongside Viridor’s landfill gas generation plant for recycling waste energy, in Greater Manchester, UK. This pre-commercial demonstrator aims to test several services including providing energy/power balance and supporting voltage/frequency regulation [71,72]. In addition, there are some EES facilities in operation in the UK grid to support the national Grid Code realization, e.g., a ABB power networks EES facility (200 kW, 200 kWh) for fault voltage support, compensation of the intermittency wind power generation and spinning reserve , a large power flywheel EES facility (totally up to 400 MW) located at Culham, U.K. to provide on-site power and frequency regulation services with the duration of second level [42,74].
- In Japan, there are five pumped storage EES plants with approximately 7000 MW in operation, which can provide the applications for the Grid Code realization, including voltage support, frequency regulation, spinning reserve and black start . The technology of adjustable speed of rotors has been adopted.
- In China, the EES technologies including pumped storage, Li-ion batteries, and VRB flow batteries have been adopted in the operational EES facilities/plants to provide grid and distribution frequency regulation services. Some of them are direct grid-connection and others have been operated on-site alongside the existing fossil-fuelled power plants or renewable power generation. For instance, a VRB flow battery facility (2 MW, 8 WMh) combines with a total of 14 MW of Li-ion batteries at Zhangbei National Wind and Solar Energy Storage and Transmission Demonstration plant , and the demonstrated applications are mainly on the renewable integration with grids, frequency regulation, and voltage (ramping) support.
- Advanced Rail Energy Storage (ARES) LLC initially developed a new technology to storage the gravitational energy by a closed low-friction automated steel rail network system [77,78]. The electric traction-drive shuttle trains transport massive heavy masses (e.g., ballasts or concretes) between two storage yards at different elevations. Such type of utility-scale electrical energy storage systems could be designed to provide grid security and reliability based on the Grid Code requirements. The company claimed that the overall cycle (round-trip) efficiency can reach approximate 80% [77,78]. The construction of the first commercial project is currently on-going, which has a capacity of 50 MW, located in Tehachapi, California [77,78].
4. Technology Recommendations
- The EES technologies which are suitable for supporting Primary and Secondary (Frequency) Response/Control and High Frequency Response in the grids are limited to those having instant/fast response time with small-to-medium scales of energy ratings. With the EES development, hybrid EES will be one of the promising technologies. Via Hybrid EES, the technologies with large-scale energy ratings (e.g., PHS, CAES, and TES) or relatively slow response time (e.g., fuel cells and liquid air storage) will have chances to provide the above frequency regulation services. To other applications for supporting Grid Code realization, e.g., LVRT voltage support, hybrid EES also has great potential, because it can utilize different technologies’ strengths to optimize the system static and dynamic performance. Thus, it is essential to enhance the R&D in hybrid EES with relevant technologies, e.g., system integration and optimal control for hybrid EES.
- EES facilities/devices can not only directly connect to the grids, but can also install inside or close to the existing fossil-fuelled power plants and renewable power generation. From the study, CAES and TES can be considered as good candidates to be implemented in the power plants. Compressed air energy or thermal energy can be extracted from Brayton cycle, Rankine cycle or others for storage purpose, and then the stored energy can flow back to the power plant cycles when needed. Some of the existing facilities in the power plants, such as air compressors, can be cost-effectively used in “a shared base” for both the original thermodynamic cycles and the energy storage process. The technology on this topic still needs practical experience for validation.
- From the study, it is found that, compared to the well-developed electrical power system analysis software, although EES has been recognized as an important component in power systems, the available options of software for EES dynamic modelling especially to CAES, TES, flow batteries and fuel cells is relatively weak. A software tool in dynamic modelling and control of components, subsystems and complete EES systems with different technologies should be essential for providing the feasibility study and the guidelines for planning and implementing test systems and demonstration projects. The specific software tool for EES systems is also quite useful for the studies of the optimal control of EES systems and their power system applications regarding the Grid Code realization and evolution.
- Technology breakthrough to different types of EES technologies is necessary. To provide services in relation to Grid Codes, the EES performance for meeting or evaluating the grid specifications on the active power output (e.g., Figure 1), the minimum frequency response (e.g., Figure 2), the FRT/LVRT characteristics (e.g., Figure 3 and Figure 6) and other requirements need further study, improve and optimize. In addition, from the view of energy/power saving with EES propagation in the grids, the cycle efficiencies of EES technologies especially to CAES, TES, fuel cells and liquid air storage must be improved. One approach is the intelligent concept (or system) design, such as adiabatic CAES, i.e., the integration of CAES and TES (the cycle efficiency can be improved from 42% to ~70%, [2,4]); another way is to develop the innovative efficient energy conversion components or to improve the existing energy conversion units in the concerned EES systems.
Conflicts of Interest
- The Office of Gas and Electricity Markets (Ofgem), UK Government. Available online: https://www.ofgem.gov.uk/licences-industry-codes-and-standards/industry-codes/electricity-codes/grid-code (accessed on 19 April 2018).
- Luo, X.; Wang, J.; Dooner, M.; Clarke, J. Overview of current development in electrical energy storage technologies and the application potential in power system operation. Appl. Energy 2015, 137, 511–536. [Google Scholar] [CrossRef]
- Robyns, B.; Saudemont, C.; Hissel, D.; Roboam, X.; Sareni, B.; Pouget, J. Electrical Energy Storage in Transportation Systems; Electrical Engineering Series; Wiley Publishing: Hoboken, NJ, USA, 2016. [Google Scholar]
- Amirante, R.; Cassone, E.; Distaso, E.; Tamburrano, P. Overview on recent developments in energy storage: Mechanical, electrochemical and hydrogen technologies. Energy Convers. Manag. 2017, 132, 372–387. [Google Scholar] [CrossRef]
- Gopstein, A.M. Energy Storage & the Grid—From Characteristics to Impact [Point of View]. Proc. IEEE 2012, 100, 311–316. [Google Scholar] [CrossRef]
- Whittingham, M.S. History, Evolution, and Future Status of Energy Storage. Proc. IEEE 2012, 100, 1518–1534. [Google Scholar] [CrossRef]
- Etxegarai, A.; Eguia, P.; Torres, E.; Buigues, G.; Iturregi, A. Current procedures and practices on grid code compliance verification of renewable power generation. Renew. Sustain. Energy Rev. 2017, 71, 191–202. [Google Scholar] [CrossRef]
- Etxegarai, A.; Eguia, P.; Torres, E.; Iturregi, A.; Valverde, V. Review of grid connection requirements for generation assets in weak power grids. Renew. Sustain. Energy Rev. 2015, 41, 1501–1514. [Google Scholar] [CrossRef]
- Al-Shetwi, A.Q.; Sujod, M.Z.; Ramli, N.L. A review of the fault ride through requirements in different Grid Codes concerning penetration of PV system to the electric power network. ARPN J. Eng. Appl. Sci. 2015, 10, 9906–9912. [Google Scholar]
- Transmission System Operator for UK, Grid Code, Issue 5, Revision 21, UK Nationalgrid. 2017. Available online: http://www2.nationalgrid.com/UK/Industry-information/Electricity-codes/Grid-code/The-Grid-code/ (accessed on 19 April 2018).
- Christiansen, W.; Johnsen, D.T. Analysis of Requirements in Selected Grid Codes. Technical Report. 2006. Available online: http://0-bibing.us.es.fama.us.es/proyectos/abreproy/70370/fichero/24.+Analysis+of+the+requirements+in+selected+Grid+Codes.pdf (accessed on 19 November 2017).
- Rajský, F.; Donsión, M.P. Comparison of transmission and distribution systems in the Czech Republic and Spain. In Proceedings of the International Conference on Renewable Energies and Power Quality, Santander, UK, 12–14 March 2008; Volume 1, pp. 485–492. [Google Scholar]
- National Development and Reform Commission, the Grid Operation Code DL/T 1040, China. 2007. Available online: http://www.doc88.com/p-6911574628424.html (accessed on 16 December 2017).
- Rated Voltage Levels of China National Grid, EEPW Website. 8 December 2016. Available online: http://www.eepw.com.cn/article/201612/341323.htm (accessed on 16 February 2018).
- Electricity Transmission, Australian Energy Regulator Published, Australian Government Website. Available online: https://www.aer.gov.au/system/files/Chapter%205%20%20Electricity%20transmission%202009.pdf (accessed on 16 February 2018).
- A Dictionary on Electricity, Project Report, a Joint Project of CIGRE and AHEF, Electricity in Australia. Available online: http://www.ewh.ieee.org/r10/nsw/subpages/history/electricity_in_australia.pdf (accessed on 18 February 2018).
- Austrian Power Grid, Transmission System Operator for Austria. Available online: http://www.apg.at (accessed on 22 February 2018).
- Technische und Organisatorische Regeln Für Betreiber und Benutzer von Netzen, Hauptabschnitt D4: Parallelbetrieb von Erzeugungsanlagen mit Verteilernetzen, E-control, Ver 2.1. 2013. Available online: https://www.e-control.at/documents/20903/26585/TOR_D4_V2_1_040913.pdf/1908f104-70d8-4511-b2ce-2e10ac3e9e50 (accessed on 26 February 2018).
- Compania Naţională de Transport al Energiei Electrice Transelectrica S.A. Codul Tehnical Retelei Electrice de Transport, Aprobat Prin Ordinul ANRE nr. 2004. Available online: http://www.transelectrica.ro/documents/10179/33158/cod_ret_ro.pdf/5cf5bb39-2efb-48f7-9ebc-491dfdb7d6e0 (accessed on 2 March 2018).
- E.ON Netz GmbH, Annexe EON HV Grid Connection Requirements. Technical Report. 2006. Available online: http://www.pvupscale.org/spip.php?article13 (accessed on 7 May 2017).
- Hirst, E. U.S. Transmission Capacity: Present Status and Future Prospects. Technical Report; 2004. Available online: https://www.energy.gov/sites/prod/files/oeprod/DocumentsandMedia/transmission_capacity.pdf (accessed on 7 May 2017).
- Edison Electric Institute (EEI). State Generation & Transmission Siting Directory. 2013. Available online: http://www.pvupscale.org/IMG/pdf/D4_2_DE_annex_A-3_EON_HV_grid_connection_requirements_ENENARHS2006de.pdf (accessed on 8 May 2017).
- EirGrid, EirGrid Grid Code Version 6.0. 2015. Available online: http://www.eirgridgroup.com/site-files/library/EirGrid/GridCodeVersion6.pdf (accessed on 9 May 2017).
- Documentation Technique de Reference, RTE—Transmission System Operator for France. 2012. Available online: http://clients.rte-france.com/htm/fr/mediatheque/telecharge/reftech/03-05-13_complet.pdf (accessed on 9 October 2017).
- Andersen, F.M.; Jensen, S.G.; Larsen, H.V.; Meibom, P.; Ravn, H.; Skytte, K.; Togeby, M. Analysis of Demand Response in Denmark. Risø National Laboratory, 2006. Available online: http://www.ea-energianalyse.dk/reports/511_Analyses_of_Demand_Response_in_Denmark.pdf (accessed on 15 August 2017).
- Walloon Energy Commission. Grid Code for the Local Transmission System Operator; Walloon Energy Commission: Wallonia, Belgium, 2007. [Google Scholar]
- Cronin, T. An overview of grid requirements in Denmark and the DTU advanced grid test facility in Osterid. In Proceedings of the 1st International Workshop on Grid Simulator Testing of Wind Turbine Drivetrains, Boulder, CO, USA, 13–14 June 2013. [Google Scholar]
- Berndt, H.; Hermann, M.; Kreye, H.D.; Reinisch, R.; Scherer, U.; Vanzetta, J. TransmissionCode 2007: Network and System Rules of the German Transmission System Operators. 2007. Available online: https://www.bdew.de/internet.nsf/id/A2A0475F2FAE8F44C12578300047C92F/$file/TransmissionCode.pdf (accessed on 15 April 2017).
- Nordic Grid Code 2007—Nordic Collection of Rules. 2007. Available online: https://www.entsoe.eu/fileadmin/user_upload/_library/publications/nordic/planning/070115_entsoe_nordic_NordicGridCode.pdf (accessed on 16 May 2017).
- Energinet, the Danish Ministry of Energy, Utilities and Climate, Technical Regulation for Thermal Power Station Units of 1.5 MW and Higher: Regulation for Grid Connection TF 3.2.3, Version 5.1. 2008. Available online: http://www.energinet.dk/EN/Soeg/Sider/resultsNew.aspx?k=grid%20code (accessed on 16 May 2017).
- Published Regulation Network Codes, Commission Regulation (EU) 2016/631. Available online: https://electricity.network-codes.eu/network_codes/rfg/ (accessed on 5 April 2018).
- Hirth, L.; Ziegenhagen, I. Control Power and Variable Renewables: A Glimpse at German Data; Fondazione Eni Enrico Mattei Milano: Milano, Italy, 2013. [Google Scholar]
- Arias, I.M.I. Grid Codes Comparison. Master’s Thesis, Chalmers University of Technology, Göteborg, Sweden, 2006. [Google Scholar]
- Merino, J.; Mendoza-Araya, P.; Veganzones, C. State of the Art and Future Trends in Grid Codes Applicable to Isolated Electrical Systems. Energies 2014, 7, 7936–7954. [Google Scholar] [CrossRef]
- UK National Grid, GC0096: Energy Storage, Documents, Proposal and Workgroup. 12 January 2018. Available online: https://www.nationalgrid.com/uk/electricity/codes/grid-code/modifications/gc0096-energy-storage (accessed on 16 March 2018).
- Establishing a Network Code on Requirements for Grid Connection of Generators, Official Journal of the European Union, L112/1. 27 April 2016. Available online: https://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX%3A32016R0631 (accessed on 14 January 2018).
- EPRI-DOE. Handbook of Energy Storage for Transmission and Distribution Applications; EPRI-DOE: Palo Alto, CA, USA; Washington, DC, USA, 2003.
- Highview Power Storage: Secure, Clean Power. Highview Power. 2011. Available online: http://www.imeche.org/docs/default-source/2011-press-releases/Highview_2pager.pdf?sfvrsn=0 (accessed on 16 February 2017).
- Lawder, M.T.; Suthar, B.; Northrop, P.W.C.; De, S.; Hoff, C.M.; Leitermann, O.; Crow, M.L.; Santhanagopalan, S.; Subramanian, V.R. Battery Energy Storage System (BESS) and Battery Management System (BMS) for Grid-Scale Applications. Proc. IEEE 2014, 102, 1014–1030. [Google Scholar] [CrossRef]
- Renewable Energy Association. Energy Storage in the UK: An Overview. 2015. Available online: https://www.r-e-a.net/upload/rea_uk_energy_storage_report_november_2015_-_final.pdf (accessed on 28 December 2016).
- Pan, F.; Wang, Q. Redox Species of Redox Flow Batteries: A Review. Molecules 2015, 20, 20499–20517. [Google Scholar] [CrossRef] [PubMed]
- US Department of Energy Global Energy Storage Database. EFDA JET Fusion Flywheel. Available online: https://www.energystorageexchange.org/projects/852 (accessed on 26 September 2017).
- Sodium-Nickel-Chloride Battery, European Association for Storage of Energy. 2016. Available online: http://ease-storage.eu/wp-content/uploads/2016/07/EASE_TD_Electrochemical_NaNiCl2.pdf (accessed on 2 April 2018).
- Bignucolo, F.; Caldon, R.; Coppo, M.; Pasut, F.; Pettinà, M. Integration of Lithium-Ion Battery Storage Systems in Hydroelectric Plants for Supplying Primary Control Reserve. Energies 2017, 10, 98. [Google Scholar] [CrossRef]
- Budt, M.; Wolf, D.; Span, R.; Yan, J. A review on compressed air energy storage: Basic principles, past milestones and recent developments. Appl. Energy 2016, 170, 250–268. [Google Scholar] [CrossRef]
- Energy Storage Association. Frequency Regulation: Executive Summary & Discussion. Available online: http://energystorage.org/energy-storage/technology-applications/frequency-regulation (accessed on 26 April 2017).
- E.ON Netz GmbH. Grid Code—High and Extra High Voltage. April 2006. Available online: http://www.pvupscale.org/IMG/pdf/D4_2_DE_annex_A-3_EON_HV_grid_connection_requirements_ENENARHS2006de.pdf (accessed on 28 July 2016).
- Raju, M.; Khaitan, S.K. Modeling and simulation of compressed air storage in caverns: A case study of the Huntorf plant. Appl. Energy 2012, 89, 474–481. [Google Scholar] [CrossRef]
- Enhanced Frequency Response (EFR), UK National Grid. Available online: https://www.nationalgrid.com/uk/electricity/balancing-services/frequency-response-services/enhanced-frequency-response-efr (accessed on 8 April 2018).
- What is Enhanced Frequency Response and Which Are Its Benefits? Logicenergy Company. Available online: https://www.logicenergy.com/what-is-enhanced-frequency-response-and-which-are-its-benefits/ (accessed on 8 April 2018).
- Pratt, D. Battery Storage Dominates National Grid EFR Tender Results, Energy Storage News, Solar Media Limited. 26 August 2016. Available online: https://www.energy-storage.news/news/battery-storage-dominates-national-grid-efr-tender-results (accessed on 5 April 2018).
- Cho, Y.; Shim, J.W.; Kim, S.J.; Min, S.W.; Hur, K. Enhanced frequency regulation service using Hybrid Energy Storage System against increasing power-load variability. In Proceedings of the 2013 IEEE Power & Energy Society General Meeting, Vancouver, BC, Canada, 21–25 July 2013; pp. 1–5. [Google Scholar]
- Wojcik, J.; Wang, J. Technical feasibility study of thermal energy storage integration into the conventional power plant cycle. Energies 2017, 10, 205. [Google Scholar] [CrossRef]
- Li, D.; Hu, Y.; He, W.; Wang, J. Dynamic modelling and simulation of a combined-cycle power plant integration with thermal energy storage. In Proceedings of the 23rd International Conference on Automation & Computing, Huddersfield, UK, 7–8 September 2017. [Google Scholar]
- Vaca, S.M.; Patsios, C.; Taylor, P. Enhancing frequency response of wind farms using hybrid energy storage systems. In Proceedings of the 2016 IEEE International Conference on Renewable Energy Research and Applications (ICRERA), Paris, France, 14–17 October 2016; pp. 325–329. [Google Scholar]
- Ammar, M.; Joos, G. A short-term energy storage system for voltage quality improvement in distributed wind power. IEEE Trans. Energy Convers. 2014, 29, 997–1007. [Google Scholar] [CrossRef]
- Guo, W.; Xiao, L.; Dai, S. Enhancing Low-Voltage Ride-Through Capability and Smoothing Output Power of DFIG with a Superconducting Fault-Current Limiter–Magnetic Energy Storage System. IEEE Trans. Energy Convers. 2012, 27, 277–295. [Google Scholar] [CrossRef]
- Serban, E.; Ordonez, M.; Pondiche, C. Voltage and Frequency Grid Support Strategies Beyond Standards. IEEE Trans. Power Electron. 2017, 32, 298–309. [Google Scholar] [CrossRef]
- Bignucolo, F.; Cerretti, A.; Coppo, M.; Savio, A.; Turri, R. Effects of Energy Storage Systems Grid Code Requirements on Interface Protection Performances in Low Voltage Networks. Energies 2017, 10, 387. [Google Scholar] [CrossRef]
- Le, H.T.; Santoso, S. Operating compressed-air energy storage as dynamic reactive compensator for stabilising wind farms under grid fault conditions. IET Renew. Power Gener. 2013, 7, 717–726. [Google Scholar] [CrossRef]
- Bignucolo, F.; Lorenzoni, A. Transmission and distribution networks regulation through dedicated cableway plants. In Proceedings of the IEEE AEIT Annual Conference—From Research to Industry: The Need for a More Effective Technology Transfer, Trieste, Italy, 18–19 September 2014; pp. 1–6. [Google Scholar]
- Bignucolo, F.; Savio, A.; Raciti, A. Cableway Storage System regulation to supply ancillary services to the distribution and transmission network. In Proceedings of the IEEE 50th International Universities Power Engineering Conference (UPEC), Stoke on Trent, UK, 1–4 September 2015; pp. 1–6. [Google Scholar]
- Bignucolo, F.; Cerretti, A.; Coppo, M.; Savio, A.; Turri, R. Impact of Distributed Generation Grid Code Requirements on Islanding Detection in LV Networks. Energies 2017, 10, 156. [Google Scholar] [CrossRef]
- Energy Storage Association. Variable Speed Pumped Hydroelectric Storage. Available online: http://energystorage.org/energy-storage/technologies/variable-speed-pumped-hydroelectric-storage (accessed on 16 August 2017).
- Toshiba Corporation. Adjustable Speed Pumped Storage. Available online: http://www.toshiba.co.jp/thermal-hydro/en/hydro/products/pump/storage.htm (accessed on 18 July 2017).
- Smart Storage Pty Ltd. (Trading as Ecoult). White Paper—Public-Domain Test Data Showing Key Benefits and Applications of the UltraBattery. January 2014. Available online: http://www.ecoult.com/images/files/whitepapers/Ecoult_UltraBattery_White_Paper_General_Version.pdf (accessed on 23 August 2017).
- Altair Nanotechnologies Inc. Advanced Energy Storage Systems for Frequency Regulation. White Paper. Available online: http://en.escn.com.cn/Tools/download.ashx?id=130 (accessed on 12 June 2016).
- Spahic, E.; Pieschel, M.; Alvarez, R.; Kuhn, G.; Hild, V.; Beck, G.; Platt, N. Power Intensive Energy Storage and Multilevel STATCOM for Frequency and Voltage Grid Support, the Proceedings of CIGRE Session 2016. Available online: http://www.ptd.siemens.de/C4-110_CIGRE2016_SVCPLUSFS_final.pdf (accessed on 12 September 2017).
- Ecoult Energy Storage Solutions, Case Study: PJM Interconnection (PA, US) Regulation Services. Available online: http://www.ecoult.com/component/phocadownload/category/3-case-studies?download=3:ecoult-case-study_regulation-services_pjm-interconnection_pa_usa (accessed on 12 September 2017).
- Ecoult Energy Storage Solutions, Ecoult Megawatt Scale Energy Storage. Available online: https://www.parliament.nsw.gov.au/committees/DBAssets/InquiryOther/Transcript/8056/CSIRO%20attachment%201a%20-%20Hampton.PDF (accessed on 18 September 2017).
- Highview Power Storage. Pre-Commercial LAES Technology Demonstrator: Transforming Waste. Available online: http://www.highview-power.com/pre-commercial-laes-technology-demonstrator/ (accessed on 25 September 2017).
- US Department of Energy Global Energy Storage Database. Pre-Commercial Liquid Air Energy Storage Technology Demonstrator. Available online: https://www.energystorageexchange.org/projects/2163 (accessed on 25 September 2017).
- ABB Group. ABB Commissions Dynamic Energy Storage Installation in the UK. Available online: http://www.abb.com/cawp/seitp202/31c5b55bad616492c1257895002628e1.aspx (accessed on 26 September 2017).
- EUROfusion. JET Flywheels: Research for Tomorrow’s Energy Supply. Available online: https://www.euro-fusion.org/fusion/jet-tech/jets-flywheels/ (accessed on 26 April 2017).
- US Department of Energy Global Energy Storage Database. Available online: https://www.energystorageexchange.org/projects/ (accessed on 17 June 2017).
- The Electrical Energy Storage Magazine (EES International). Energy Storage in China. 2014. Available online: http://www.ees-magazine.com/energy-storage-in-china/ (accessed on 15 March 2017).
- Advanced Rail Energy Storage, ARES Nevada, Ares North America. Available online: https://s3.amazonaws.com/siteninja/multitenant/assets/21125/files/original/All_About_ARES_-_070616.pdf (accessed on 18 March 2018).
- Railway Solution for Grid-Scale Energy Storage, Ares North America. 12 May 2016. Available online: https://www.aresnorthamerica.com/article/8957-railway-solution-for-grid-scale-energy-storage (accessed on 18 March 2018).
|UK National Electricity Transmission Rated Voltage||Allowed Operating Range 1|
|400 kV||400 kV ± 5%|
|275 kV||275 kV ± 10%|
|132 kV||132 kV ± 10%|
|Below 132 kV||±6%|
|Country Names||Allowed Operating Voltages|
|Great Britain||400, 275, 132 kV and below|
|Germany||380, 220 and 110 kV; 155 kV for offshore grid-connection|
|Ireland||400, 220 and 110 kV|
|France||Extra High Voltage (400, 225 and 150 kV) and High Voltage (90 and 63 kV)|
|Italy||380, 220 and 150 kV|
|Belgium||70–30 and 380–150 kV|
|Denmark||400, 220, 150 and 132 kV|
|Austria||380, 220 and 110 kV|
|Romania||750, 400 and 220 kV|
|Poland||750, 400, 220 and 110 kV|
|Australia||500, 330, 275, 220, 132 and 66 kV|
|China||Extra High Voltage (1000, 750, 500 and 330 kV), High Voltage (220, 110 and 66 kV)|
|Country||Frequency Interval||Country||Frequency Interval|
|Great Britain||49.5–50.5 Hz||Ireland||49.8–50.2 Hz|
|Germany||49.5–50.5 Hz||Italy||49.9–50.1 Hz|
|France||49.5–50.5 Hz||Poland||49.5–50.5 Hz|
|Belgium||49.5–50.5 Hz||Denmark||49.9–50.1 Hz|
|Austria||49.5–50.5 Hz||Romania||49.5–50.5 Hz|
|Australia||49.75–50.25 Hz||China||49.8–50.2 Hz|
|Country||Critical Frequency Interval||Country||Frequency Interval|
|Great Britain||47.0–52.0 Hz||Ireland||47.0–52.0 Hz|
|Germany||47.0–52.0 Hz||Italy||47.5–51.5 Hz|
|France||47.0–52.0 Hz||Poland||47.0–52.0 Hz|
|Belgium||47.0–52.0 Hz||Denmark||47.5–51.0 Hz|
|Austria||47.5–51.5 Hz||Romania||47.0–52.0 Hz|
|Australia||47.0–52.0/55.0 Hz||China||48.0–51.0 Hz|
|51.5–52.0 Hz||Operation for a period at least 15 min is required for each time the frequency in this range.|
|51.0–51.5 Hz||Operation for a period at least 90 min is required for each time the frequency in this range.|
|49.0–51.0 Hz||Continuous operation is required.|
|47.5–49.0 Hz||Operation for a period at least 90 min is required for each time the frequency in this range.|
|47.0–47.5 Hz||Operation for a period at least 20 s is required for each time the frequency in this range.|
|Type of Frequency Response||Information|
|Primary (Frequency) Response||The minimum increase in the unit’s active power output provided within the duration of 10–30 s after the time of the start of the frequency fall (Figure CC.A.3.2 in )|
|Secondary (Frequency) Response||The minimum increase in the generating unit’s active power output provided within the duration of 30 s to 30 min after the start of frequency fall (Figure CC.A.3.2 in )|
|High Frequency Response||The reduction in the generating unit’s active power output in response to an increase in system frequency above the target frequency; it must provide within 10 s after the start of the frequency increase and must be maintained thereafter|
|Country||Type of Relevant Strategy||Response Time Relevant Information|
|GB||Primary (Frequency) Response||see Table 6|
|Secondary (Frequency) Response|
|High Frequency Response|
|Ireland||Primary Frequency Control||Taking place up to 30 s after a change in frequency and achieved by automatic corrective responses to frequency deviations|
|Secondary Frequency Control||Taking place from 5 s up to 10 min after the change in frequency and provided by a combination of automatic and manual actions|
|Operating Reserve||Primary Operating Reserve||Activate at the frequency minimum which occurs between 5 s and 15 s after an event|
|Secondary Operating Reserve||Available after 15 s from the start of the frequency fall and sustainable up to 90 s following an event|
|Tertiary Operating Reserve band 1||Available and sustainable over the period from 90 s to 5 min following an event|
|Tertiary Operating Reserve band 2||Available and sustainable over the period from 5 min to 20 min following an event|
|France, Italy||Primary Control||50% of active power increase within 15 s;|
100% of active power increase within 30 s;
100% of active power increase supplied for at least 15 min
|Secondary Control||Activate no later than 30 s after an event and its operation must end within 15 min|
|Tertiary Control||Activate during Secondary Control and maintain for no longer than 15 min|
|Germany||Primary Control||The generating unit be capable of activating 100% of active power within 30 s after an event and maintain supply for at least 15 min|
|Secondary Control||The generating unit be capable of activating 100% of active power evenly within 5 min|
|Minutes Reserve||The minutes reserve power must provide within 15 min; the delivery shall be made at a lead time of at least 7 ½ minutes at the beginning of the following quarter hour|
|Denmark||Primary Control||A frequency response of 18,000 MW/Hz is required|
|Control Reserve||If a rapid change of frequency to 49.9/50.1 Hz, the reserve shall be regulated within 2 to 3 min;|
If a frequency drop to 49.5 Hz, 50 % of the frequency controlled reserve shall be regulated upwards within 5 s; 100% of the reserve shall be regulated within 30 s
|China||Primary Frequency Control||Delay time within 3 s and the active power fully increasing within 15 s|
|Secondary Frequency Control||The active power normally increasing within 1 min|
|Technology||Power Rating (MW)||Response Time||Discharge Time||Cycle Efficiency (%)||Rated Energy (MWh)||Maturity|
|Large-scale CAES||up to 300 and more||4–12 min||1–24 h+||42–54, could up to 70||up to 2860||commercialized A-CAES demo|
|Small-scale CAES||up to 10–20||seconds to minutes||30 s–3 h||60–70, discharge 80+||0.002–0.0083||early commercialized|
|Flywheel||0.1–400 for multi units||<1 cycle, up to seconds||up to 15 min||85–95||up to 5||early commercialized|
|Lead-acid||up to 40||<1/4 cycle, milliseconds||seconds–10 h||63–80, possible to 90||0.0005–40||commercialized-mature|
|Li-ion||up to 50, maybe more||<1/4 cycle, milliseconds||minutes–hours||75–97||~0.004–10||demonstration|
|NaS||up to 50||–||seconds–hours||60–90||0.4–244.8||commercialized|
|NiCd||up to 40||<1/4 cycle, milliseconds||seconds–hours||60–83||6.75||commercialized|
|Na-NiCl2||Several MW||milliseconds||seconds–hours||75–95||Possible up to several MWh||demo/early commercialized|
|VRB||~0.03–3, possible 50||<1/4 cycle||seconds–24 h+||65–85||<60||demo/early commercialized|
|ZnBr||0.05–10||<1/4 cycle||seconds–10 h+||65–80||0.1–4||demonstration|
|PSB||up to 15||20 ms||seconds–10 h+||60–75||–||developing|
|Capacitor||up to 0.05||<1/4 cycle, milliseconds||milliseconds–1 h||60–70+||–||commercialized|
|Super-capacitor||up to ~0.3||<1/4 cycle, milliseconds||milliseconds–1 h||84–97||0.0005||developing-demonstration|
|SMES||0.1–10||<1/4 cycle, milliseconds||milliseconds–30 min||95–98||up to 0.015||demo-early commercialized|
|Solar fuel||could up to 10, developing 20||–||1–24 h+||30, possible up to ~50||–||developing|
|Hydrogen Fuel cell||up to ~60||seconds to minutes||seconds to 24 h+||up to ~70||0.312, developing 39||developing-demonstration|
|Thermal storage||up to 300||not for rapid response||up to 24 h+||30–60, could higher||–||demo-early commercialized|
|Liquid air Storage||10–50, could up to 200||minutes||several hours||30–40, 55–80 (waste heat)||2.5||developing-demonstration|
|Type of Frequency Control (Response) Strategy||Grid Code Specifications to Response Time and Duration [10,28,31,37]||Available and Promising EES Options (the Maturity Getting the Demonstration Stage at Least) [2,4,37,40]|
|GB: Primary (Frequency) Response||GB: the minimum increase in active power output within the duration of 10–30 s after the time of the start of frequency fall||Available: Flywheels (up to seconds, up to ~20 MW/5 MWh);|
Lead-acid, Li-ion, NaS and NiCd batteries (milliseconds, up to ~50 MW/40 MWh);
VRB and ZnBr flow batteries (milliseconds, up to ~50 MW/60 MWh);
SMES (milliseconds, short storage duration, up to 10 MW/0.015 MWh);
Promising: Hybrid EES (at least one fast response technology needs to be used in hybrid EES)
|Germany: Primary Control||Germany: the generating unit be capable of activating 100% of active power within 30 s after an event and maintain supply for at least 15 min|
|GB: Secondary (Frequency) Response||GB: the minimum increase in active power output within the duration of 30 s to 30 min after the time of start of frequency fall||Besides the technologies listed for Primary (Frequency) Response/Control, the below technologies have potentials:|
Fuel cells (seconds to minutes, up to ~60 MW)
(seconds, up to 10–20 MW)
|Germany: Secondary Control||Germany: the generating unit be capable of activating 100% of active power evenly within 5 min|
|GB: High Frequency Response||GB: the minimum decrease in active power output within the duration of 10 s after the time of the start of the frequency increase and maintained thereafter||Available EES options could be the same as the technology candidates which can provide Primary (Frequency) Response/Control. However, if the EES has two separate processes for charging and discharging, it requires a particular attention.|
|Germany: Minutes Reserve||Germany: the minutes reserve power must provide within 15 min; the delivery shall be made at a lead time of at least 7 ½ minutes at the beginning of the following quarter hour||Besides the technologies listed for Primary (Frequency) Response/Control, the below could provide this service if they working on their standby modes:|
PHS (minutes, up to 5000 MW/8000 MWh);
CAES (minutes, ~300 MW/2860 MWh);
TES (minutes, up to 300 MWh)
|Ancillary Service Application Areas||Application Characteristics and Specifications||Experienced and Promising EES Technology Options|
|Low voltage ride-through||A few MW to 10 MW, response time (~milliseconds), discharge duration (~minutes)||Flywheels, batteries, flow batteries, SMES, hybrid EES|
|Voltage regulation and control||Up to a few of MW, response time (milliseconds), discharge duration (up to minutes)||Batteries, flow batteries, SMES, flywheels, hybrid EES|
|Grid fluctuation suppression||MW level, response time (milliseconds), duration (up to ~minutes)||batteries, flywheels, flow batteries, SMES, hybrid EES|
|Enhanced frequency response||Delivering 1–50 MW of response within 1 s to frequency deviations, duration at rated power for at least 30 min||batteries, flywheels; possible flow batteries, SMES, hybrid EES|
|Spinning reserve||MW level, response time (up to a few seconds), discharge duration (30 min to a few hours)||Batteries, small-scale CAES, flywheels, flow batteries, SMES, fuel cells, hybrid EES|
|Load following||MW level (up to hundreds of MW), response time (up to ~1 s), duration (minutes to a few hours)||batteries, flow batteries, SMES, fuel cells, hybrid EES|
© 2018 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).
Share and Cite
Luo, X.; Wang, J.; Wojcik, J.D.; Wang, J.; Li, D.; Draganescu, M.; Li, Y.; Miao, S. Review of Voltage and Frequency Grid Code Specifications for Electrical Energy Storage Applications. Energies 2018, 11, 1070. https://doi.org/10.3390/en11051070
Luo X, Wang J, Wojcik JD, Wang J, Li D, Draganescu M, Li Y, Miao S. Review of Voltage and Frequency Grid Code Specifications for Electrical Energy Storage Applications. Energies. 2018; 11(5):1070. https://doi.org/10.3390/en11051070Chicago/Turabian Style
Luo, Xing, Jihong Wang, Jacek D. Wojcik, Jianguo Wang, Decai Li, Mihai Draganescu, Yaowang Li, and Shihong Miao. 2018. "Review of Voltage and Frequency Grid Code Specifications for Electrical Energy Storage Applications" Energies 11, no. 5: 1070. https://doi.org/10.3390/en11051070