A123 Systems: Advanced Battery Energy Storage for Renewable Integration

A123 Systems Advanced Battery Energy Storage for Renewable Integration Charles Vartanian Neil Bentley Member A123 Systems cvartaniana123systemscom Abstract This paper outlines A123s early ground breaking grid battery systems that are in commercial service today at multiMW scale Key characteristics of A123s NanophosphateTM Liion battery are described Then the current use of A123s MWscale battery systems for Frequency Regulation is described The paper then discusses how these characteristics and capabilities implemented in A123s current multiMW scale battery systems will be extended and applied for renewable integration in two Government funded smart grid demonstration projects 1 our Michigan funded Smart Grid Storage demo of PV integration with Detroit Edison and 2 our DoE funded Tehachapi Wind Integration project with Southern California Edison Index TermsAdvanced batteries Ancillary services Energy storage Frequency regulation Renewable energy Renewable integration INTRODUCTION As of late 2010 A123 Systems has deployed over 36 MWs of advanced battery based grid connected energy storage systems These systems use A123s proprietary NanophosphateTM Liion battery chemistry Characteristics of this battery chemistry allow creation of batterybased systems capable of dynamic exchange of real power with the connected grid and thus expand the range of applications and values beyond conventional catch and release temporal shifting of energy as already done successfully at significant scale today with pumped hydro storage The enhanced characteristics of advancedbattery based grid systems that allow creation of new expanded functionality include very high efficiency very high cycle life and scalability Today grid applications leveraging these advanced battery characteristics include Frequency Regulation The same characteristics that allow for use of batteries at multiMW scale for Frequency Regulation can also be applied to an emerging grid challenge integration of intermittent renewable generation Study of one major US market has identified an indirect opportunity for storage to support integration of more renewable energy ie supporting more renewables by meeting the electric systems expected increase in required Frequency Regulation capacity as the proportion of intermittent renewable resources versus traditional resources increases A123s own grid simulation studies show that there are additional gridsupportive benefits relevant to renewable integration specifically increased system stability through use of large scale multiMW dynamicallyresponsive energy storage systems Underlying all of A123s energy storage products is our NanophosphateTM battery cathode Key resulting attributes of A123s advanced iron phosphate Liion battery include high power safety and life While this paper focuses on system level applications a few metrics for our NanophsophateTM battery help illustrate how the characteristics of our battery enable our kW to multiMW scale grid storage systems POWER at the cell level our batteries can fully discharge and charge at over a 10C rate or fully charge or discharge within 6 minutes SAFETY the Nanophosphate TM cell releases relatively less oxygen when exposed to elevated temperatures therefore poses lower fire risk relative to other Liion chemistries In an independent report published by Sandia National Labs Pete Roth states the significant reduction in cell heating rates for the nanophosphate material is attributable to the lack of oxygen decomposition from the cathode material 1 LIFE is measured both in cycles and shelf life An indicative measures of A123 batterys high life are 8000 full depth of discharge cycles and 20 year calendar life under specified conditions A123 cylindrical 26650 products delivers over 8000 cycles at 1C1C and 100DOD with little impedance growth and calendar life projecting 10 years in automotive and grid environments 9781612847887112600 2011 IEEE 0 20 40 60 80 100 120 0 20 40 60 80 100 120 0 2000 4000 6000 8000 10000 12000 DC Impedance initial Discharge Capacity initial Cycle Number 1C1C 100 depth of discharge DOD cycling Fig 1 Cycle life of A123 cylindrical cell on 1C1C 100 DOD cycling I A123S SMART GRID STABILIZATION SYSTEM Since 2008 A123 has deployed over 20 MW of advanced battery systems The systems in commercial operation today are owned and operated by our developer partner AES Storage Recent deployed projects are comprised of multi unit arrays of A123s Smart Grid Stabilization System SGSS Fig 2 shows a portion of a 12 MW array of A123s SGSS units that went into commercial service in 2009 Fig 2 photo of multiple SGSS units operating in a 12 MW grid storage system Fig 3 is an artist rendering of a single SGSS unit Fig3 Artist rendering of an A123 SGSS Unit The basic characteristics of each SGSS unit include 1 2 MW power and 500 kWh energy capacity 2 20ms response time for power output changes in response to control signals 3 System roundtrip efficiency near 90 4 Cyclelife ranging from near 10000 to multiple 100000s depending on actual Wh throughput Wh throughput is proportional to the average depth of discharge per cycle and the number of cycles per time period A Ancillary Service Our grid systems that have been deployed todate are used for Frequency Regulation and Spinning Reserves In deregulated US wholesale markets these are defined Ancillary Services and are procured through bidbased market mechanisms Ancillary Services are defined in the FERC Open Access Transmission Tariff ProForma Tariff 2 In simplified terms Spinning Reserves is a form of back up where a system is synchronized to the grid but doesnt deliver power unless called upon typically after a system outage event Frequency Regulation requires power capacity to be continuously varied across a defined power MW range the marketcleared bid capacity in response to an Automatic Generator Control AGC signal An AGC signal for a unit performing Frequency Regulation will typically raise and lower the power output in inverse proportion to the deviation of system frequency from nominal 60Hz in the US Since electrical grids continuously oscillate bidirectionally plus and minus around the nominal system frequency under normal conditions this allows implementation of storage based grid systems including mechanical as well as battery based grid systems that exchange energy bidirectionally with the grid frequently enough to remain in continuous service despite limited energy capacity Thus our SGSS can be implemented with a powertoenergy ratio of 41 to perform this service with an efficient amount of battery capacity Fig 4 is a conceptual simplified diagram of momentto moment varying power output required when a grid resource is performing Frequency Regulation This graphic points out the similarity between the varying output level for Frequency Regulation and a hybrid electric vehicle Fig 4 Conceptual illustration of varying power output for Frequency Regulation cycling around an average plant power output value Fig 5 is another conceptual illustration of Frequency Regulation for one of the deregulated markets in the US the California Independent System Operator CAISO Fig 5 CAISOs Regulation Requirement Illustration1 The following CAISO description of Regulation is informative for its clear identification that sufficient Regulation resources are needed to meet reliability standards The CAISO shall maintain sufficient resources immediately responsive to AGC in order to provide sufficient Regulation service to allow the CAISO Balancing Authority Area to meet NERC2 and WECC3 reliability standards 1 4 p79 2 North American Electric Reliability Corporation 3 Western Electricity Coordination Council including any requirements of the NRC by continuously balancing Generation to meet deviations between actual and scheduled Demand and to maintain Interchange Schedules4 As of late 2010 A123 has shipped 36 MW of grid storage systems for commercial service primarily for provision of Ancillary Services Over the next several years A123 will be working with US utility partners for government cofunded demonstration of our proven battery technology for a several advanced applications including renewable integration Two of our upcoming demonstration projects are described next II MPSC SMART GRID DEMO FOR PV INTEGRATION In November of 2009 A123 was awarded a grant by the Michigan Public Service Commission MPSC under the LIEEF established as part of 2000 PA 141 MCL 46010d6 With this grant A123 and partner DTE Energy will demonstrate the technical and economic benefits of combining a fast response Liion battery system with a large photovoltaic array More specifically the project will design manufacture and install a 500kW 250kWh battery system which leverages the successfully commercially deployed SGSS in conjunction with a groundbased 500kW photovoltaic PV system5 within the State of Michigan The system will be integrated with and dispatchable by Detroit Edisons Distributed Resource System Operations Center DRSOC Fig 6 Conceptual highlevel one line drawing of MPSC Smart Grid Demo for PV Integration The system will be installed at the distribution level on a circuit of sufficient interest eg circuit loading under peak loading for the selected program demonstration items CustomerRelated Benefits VAR Support Power Factor Penalty Avoidance Peak Shaving DistributionRelated Benefits Frequency Regulation 4 Blacklines for NonGeneration Resources Fourth Replacement CAISO Tariff Section 8231 Regulation Service CAISO P18 May 18 2010 5 Photovoltaic system primarily funded under a separate grant administered by MPSC under 2008 PA 295 Voltage Support PV Output Shifting PV Output Leveling Demand Response o Grid Support o Distribution Circuit Peak Shaving These demonstration services will be evaluated for their ability to deliver energy savings and other system benefits Service Benefit Optimize customer energy production and utilization Customer energy charge savings Lower energy losses for utility Lower environmental impact across energy chain Manage net power flow between customer and utility Customer demand charge savings Better utility system capacity factor asset utilization Noninterference wutility protection systems Simpler interconnection for customer wunidirectional flow Balance voltage at utility interface Reduce reactive power requirement from utility Lower utility energy loss by reducing reactive power flow Customer reactive power penalty charge avoidance Improve power quality at customer facility Frequency Regulation Lower fuel use and emissions for the aggregate bulk grid system per unit of Frequency Regulation delivered by battery System installation and operation is scheduled to begin in June 2011 The system will be operated under controlled and monitored conditions for approximately 1 year At the conclusion of the MPSC demonstration the system will become part of DTEs Community Energy Storage DOE Smart Grid Demonstration program DEOE0000229 and operate through 2014 III DOE SMART GRID DEMO FOR WIND INTEGRATION A The Tehachapi Wind Integration Demonstration A123s 32 MWh Liion battery system In 2008 the DoE Office of Electricity issued their funding announcement for Smart Grid Storage demonstrations FoA 36 In partnership with Southern California Edison SCE A123 applied to and was selected via this solicitation to implement and demonstrate a 32MWh A123 Liion battery system for wind integration as implemented on the utility side of the bulk network transmission system in the Tehachapi wind farm area of Southern California The intent is to use proven underlying battery storage and inverter technology in grid storage applications that are not yet common practice nor fully commercialized The A123 battery system to be deployed in 2012 and demonstrated by SCE and A123 under monitored conditions for 2 years will be an 8 MW battery system with 4 hour duration capacity The battery capacity will be interfaced to the grid with an MVArated inverter with real and reactive power capacity Figure 6 below is a conceptual rendering of the planned system Fig 6 Conceptual illustration of A123s Tehachapi Battery System This demonstration system will be operated under controlled and monitored conditions for a 2 year period during which 13 functionalities within three general groupings will be executed and measured TransmissionRelated Uses Voltage Support Grid Stabilization Decreased Transmission Losses Diminished Congestion Increased System Reliability Load Shed Deferral Deferred Transmission Investment Optimize Size and Cost of Renewable EnergyRelated Transmission SystemRelated Uses Provide System Capacity Resources Adequacy Renewable Energy Integration Smoothing Wind Generation OutputShifting ISO MarketRelated Uses Frequency Regulation SpinNonSpin Replacement Reserves Deliver Ramp Rate Energy Price Arbitrage Prior to the 2014 conclusion of the DoE funded test and demo period the project team will submit its findings to the California Public Utility Commission providing input that will be used to determine if ongoing operation of this system will return adequate value to SCEs rate payers to justify its ongoing operation as a utility TD rate based asset B Storage to Improve Dynamic Stability early power system simulations to support the Tehachapi demo project The CAISO used grid simulation studies including dynamic stability to assess the impacts of meeting Californias 20 Renewable Portfolio Standard 4 No serious transient stability or posttransient stability problems were identified in the referenced CAISO 20 RPS study report But the referenced report also noted Spain has recognized the potential problem of large amounts of wind integration in regard to stability conditions under system fault6 Dynamic stability simulations that A123 performed earlier in 2008 to evaluate storages capacity to support very high wind penetration in California 5 is consistent with the CAISO report citations above A123s own dynamic simulations of high wind penetration scenario in California did not identify any stability criteria violations but there were results for faultoutage simulation cases for which adding storage capacity with frequency droop response significantly improved the modeled systems frequency response to an outage When comparing with versus without storage scenarios the with dynamically controlled frequency droop control storage scenarios had superior frequency recovery as illustrated in the graphics in Fig 7a and Fig 7b below 6 4 p108 Fig7a Declining bus frequencies in a dynamic simulation run for a highwind scenario without storage added to the modeled grid Fig7b Damped and stable bus frequencies in a dynamic simulation run for the same highwind scenario but with storage added to the modeled grid Improving postoutage system frequency recovery absent reliability criteria violation wont justify the deployment of storage But if storage is deployed for any other reason like Frequency Regulation market participation the added frequency responsive storage will support the integration of relatively more intermittent renewable resources into the shared electrical system IV CONCLUSION As of late 2010 A123 has shipped 36 MW of grid energy storage systems These systems have been deployed for commercial service using A123s independently tested and proven NanophosphateTM advanced Liion batteries that have been used in commercial hand tool and transportation applications for over 5 years These grid storage systems are in service today providing Ancillary Services including Frequency Regulation and Spinning Reserves in open deregulated electricity markets in the US and internationally A123 is extending the application of our existing commercial grid storage systems for delivery of an expanded set of functionalities that will support the integration of renewable resources reliably into electric networks and grids Towards that end we have embarked on two government co funded demonstrations that will demonstrate a range of storage applications that will support and facilitate PV and wind generation integration These projects also benefit from the participation of industry leading utilities Detroit Edison and Southern California respectively These utilities operational experience and real world challenges provide an ideal context for the development and demonstration of expanded use of energy storage technology for enhancement of grid performance We anticipate that the upcoming demonstration projects modeling and demonstration of grid storage system functionalities that support integrating intermittent renewable resources will help the wider power industry better understand how and where energy storage will effectively contribute to meeting the challenge of integrating intermittent renewable resources that will green our energy consumption but offer significant grid operating challenges REFERENCES 1 Peter Roth Thermal Ramp Abuse Test Evaluation of Baseline A213 Cells Sandia National Laboratories 9072007 p6 2 FERC Order 888A Promoting Wholesale Competition Through Open Access Nondiscriminatory Transmission Services by Public Utilities Recovery of Stranded Costs by Public Utilities and Transmitting Utilities Appendix B Pro Forma Tariff httpwwwfercgovlegalmajordreglanddocsrm958p4000txt 3 CA Executive OrderS1408 Office of the Governor Nov 17 2008 4 C Loutan and D Hawkins Principal Investigators Integration of Renewable Resources Transmission and operating issues and recommendations for integrating renewable resources on the California ISOcontrolled grid CAISO Nov 2007 5 S Hamilton Batteries are Key to Wind Integration TD World December 2008