Tehachapi Energy Storage Project
The Tehachapi Energy Storage Project (TSP) is an operating lithium-ion battery energy storage system used for grid energy storage  located at the Monolith Substation  of Southern California Edison in Tehachapi, CA.  At the time of commissioning in 2014, it was the largest lithium-ion battery system operating in North America and one of the largest in the world.                  The TSP system can supply 32 Megawatt-hours of electricity, corresponding to 8 Megawatts of power for four continuous hours, which is sufficient for power between 1,600 and 2,400 homes.  The amount of energy stored at TSP is equivalent to that stored in more than 2,000 hybrid electric vehicles.  TSP is considered to be a modern-day energy storage pioneer with significant accomplishments that have proven the viability of utility-scale energy storage using lithium-ion technology.  While originally envisioned as a research and development project,   TSP continues operation today as a distribution-level resource for Southern California Edison. 
|Tehachapi Energy Storage Project|
Overhead View of Tehachapi Energy Storage Project, Tehachapi, CA
|Location||Tehachapi, Kern County, CA|
Latitude and Longitude:
|Owner(s)||Southern California Edison|
|Operator(s)||Southern California Edison|
|Nameplate capacity||8 MW|
|Storage capacity||32 MWh|
The TSP system was one of the first to demonstrate the assembly of a large quantity of lithium-ion batteries into a single operating system on the order of Megawatts of power and tens of Megawatt-hours of energy to provide electric grid support. The project uses automotive-grade batteries and demonstrates the synergies between batteries for the automotive and electric grid sectors.  The TSP system was designed and evaluated using an application-driven approach.  Energy storage for the wind farms at Tehachapi Pass have been extensively studied before, including the impacts of energy storage at Monolith Substation.  As Edison International, parent company of Southern California Edison (SCE), describes, there is a continued interest in energy storage from utilities, along with a view that there will be technical innovations to help with managing the grid in a more efficient and reliable manner.  The history of seismic activity in Kern County,   including damage to substation structures,  created some system design challenges. Since commissioning in 2014, the area has experienced not only seismic activity,  but also flash floods and subsequent mudslides.    The TSP system is constructed of 608,832 lithium-ion battery cells that are enclosed into 10,872 modules of 56 cells each and then stacked in 604 racks.   A bi-directional inverter or Power Conversion System (PCS) provides the DC to AC conversion during battery discharging and AC to DC conversion for battery charging.  The batteries are housed in a 6,300 square foot building.   
|Specifications for Mini-System and Full System |
|Mini-System at Pomona, CA||Full System at Tehachapi, CA|
|Footprint||77 square feet||6300 square foot building|
|Power||30 kW||8 MW|
|Energy||116 kWh||32 MWh|
|Inverter||One Mini-Cabinet||Two 40-foot containers|
TSP is an example of commercially-available, large-scale energy storage for electric grid applications   and part of the increasing fleet of energy storage systems.  The deployment of TSP has been part of the key foundation in developing energy storage in California  and for increasing grid reliability overall.  TSP is also providing improved integration and opportunities for better operation of renewable energy resources.  During 2009 to 2014, more than 120 grid energy storage projects were commissioned, marking a significant turning point for grid batteries.  The TSP system had a significant role in this as a large, utility-owned system providing multiple energy services using commercially available products.  One key lesson learned is the importance of subscale testing by the electric utility prior to full system deployment so that the safety and operational controls and features could be fully evaluated.   This was the first known use of a subscale system by an entity other than a manufacturer or integrator to facilitate full scale testing, commissioning, and ongoing operations.  Some of the additional lessons learned included: the challenges related to outage scheduling, challenges with interconnection agreements, benefits of component validation testing at the factories, and preparing detailed step-by-step test plans in advance.  In 2014, TSP was one of the large-scale energy storage projects in the interconnection queue for the California Independent System Operator (CAISO) with planned benefits including firming renewable generation, frequency regulation, spin/non-spin replacement reserves, ramp management, and energy price arbitrage.  The TSP system was tested using eight core tests performed by the grid operator or under market control.  Both the utility and system provider gained important perspectives and insights during the design, construction, commissioning, and operating of the TSP system.    
To evaluate the 13 operational uses, SCE defined eight tests that were designed to measure the ability of TSP to respond to the following system needs or signals: 1) Provide steady state voltage regulation at the local Monolith 66 kV bus 2) Provide steady state voltage regulation at the local Monolith 66 kV bus while performing any other tests 3) Charge during periods of high wind and discharge during low wind under SCE system operator control 4) Charge during off-peak periods and discharge during on-peak periods under SCE system operator control 5) Charge and discharge seconds-to-minutes as needed to smooth intermittent generation in response to a real-time signal 6) Respond to CAISO control signals to provide frequency response 7) Respond to CAISO control signals to provide spin/non-spin reserves 8) Follow a CAISO market signal for energy price. 
|Tehachapi Operational Uses and Tests |
|Increased System Reliability||4||X|
|Deferred Transmission Investment||5||X||X|
|Optimized Renewable-Related Transmission||6||X||X|
|System||System Capacity/Resource Adequacy||7||X||X|
|Renewable Integration (firming & shaping)||8||X|
|ISO Market||Frequency Regulation||10||X|
|Deliver Ramp Rate||12||X||X|
|Energy Price Arbitrage||13||X|
The final project report for the United States Department of Energy after system deployment concludes that TSP is a modern-day energy storage pioneer, achieving a number of significant accomplishments that have proven the viability of utility-scale energy storage using lithium-ion technology.  These accomplishments included: 
- The largest lithium-ion battery energy storage system in North America, in terms of energy capacity (32 MWh), at the time of commissioning in 2014.
- The first battery energy storage system in California specifically designed and operated as a dual-use asset, supporting utility transmission/distribution functions and operating in the competitive power market.
- The first known use of a subscale or Mini-System by an entity other than a manufacturer or integrator, to facilitate full scale testing, commissioning, and ongoing operations.
- The first battery energy storage system integrated with SCE’s systemwide Supervisory Control and Data Acquisition (SCADA) system providing high-level visibility and control to grid operators.
- The first battery energy storage system to be operated by SCE and one of the first to be interconnected, certified, and operated in the CAISO market.
- The first modern, large-scale, lithium-ion battery energy storage system installed in an SCE substation and connected to the regional transmission network.
- Serving as the foundation for subsequent SCE energy storage procurements.
Since the start of market operations in 2016, TSP has been listed in the Monthly Electric Generator Inventory of the U.S. Energy Information Administration (EIA) as an electric generator.  During that same time period, the EIA began publishing more detailed energy storage information in its Annual Electric Generator Report, including battery capacity, charge and discharge rates, storage technology types, reactive power ratings, storage enclosure types, and expected usage applications.  The operation of the TSP system has been described as a real-life example of grid-connected energy storage   and some of the initial testing included storing wind energy at night and delivering it during the day when customers need it.  The California Independent System Operator (CAISO), a grid system operator, has shared its operating experiences of TSP internationally with other grid operators as part of continued close collaborations.  CAISO has specific roles for energy storage in the energy market and TSP is an example of a Non-Generator Resource.  Non-Generator Resources in the CAISO energy market seamlessly inject and absorb energy at different times.  The ongoing operation of the TSP system continues to provide grid services in the energy matket and lessons learned for grid energy storage systems.  
One of the major benefits of the TSP system is the wide range of studies and analyses performed by multiple organizations to address various aspects of the energy market. Operational information has been used as part of developing incentives for distributed energy storage for California, New York, Hawaii, and several other states.  The Energy Management System (EMS) and EMS structure for TSP have been studied in order to develop and determine the technical, market, and regulatory requirements for energy storage systems.  The University of California, Riverside has used TSP for the stochastic valuation of energy storage in wholesale power markets to determine optimal power dispatch sequences.  The findings from this study include: 1) System performance is heavily affected by roundtrip effiency and power-to-energy ratio, 2) The optimal power-to-energy ratio for wholesale power market is much higher than the nominal configuration of 1-to-4 typically used in existing energy storage projects, 3) The majority of revenues are from frequency regulation services.  In a separate analysis, the University of California, Riverside used real market data from TSP in order to develop an optimal supply and demand bidding, scheduling, and deployment design framework based on the day-ahead and real-time market prices, location, size, efficiency, lifetime, and charge and discharge rates.  The topic of used and second-use batteries is also examined and analysis shows that by using one of the proposed bidding methods, TSP could still be profitable even after losing half of its energy capacity.  Based on the studies described above, the University of California, Riverside performed another analysis for the scenarios where battery systems are investor-owned and independently-operated and participating in existing markets.  The study proposes a new optimization framework to coordinate the operation of large, price-maker, and geographically dispersed energy storage systems in a nodal transmission-constrained energy market.  The Edison Electric Institute (EEI), which represents all investor-owned utilities in the United States, has described how TSP has capabilities to provide nearly instantaneous maximum capacity for renewables ramping, which minimizes needs for traditional backup generators.  The European Commission performs an ongoing analysis of energy storage systems, including TSP, and has global collaborations with technical experts to exchange and to learn about operating details, challenges, and best practices. 
An official ribbon-cutting ceremony, site tour, and presentation of a certificate of recognition from the California State Senate were held on September, 24, 2014.     The ceremony speakers included Doug Kim (Director of Advanced Technology, Southern California Edison), Zack Scrivner (Supervisor, Kern County Board of Supervisors), Dr. Imre Gyuk (Energy Storage Program Manager, United States Department of Energy), Dr. Seokhwan Kwak (Vice President of Marketing, LG Chem), and Romeo Agbalog (Office of State Senator, Jean Fuller - 18th District).  Tours of the control room, battery room, and inverter enclosures were provided.     Upon commissioning, TSP was selected to be a Finalist for the 2014 Innovation Award for Energy Storage North America (ESNA).  TSP is a member of the ESNA Hall of Fame.  The 2018 and 2019 Economic Round Table Reports from the Greater Antelope Valley Economic Alliance include TSP as a highlight in the Renewable Energy sections.   Kern County, CA describes TSP as a key feature in its renewable energy portfolio  for storing energy from solar power and wind power and improving grid flexibility and reliability.  Building upon TSP, Kern County continues to cultivate energy storage as providing economic development opportunities for 2020 and beyond.  In 2019, the U.S. Department of Energy featured TSP in Success Stories Spotlight: Solving Industry’s Energy Storage Challenges. 
- Eyer, Jim; Corey, Garth (February 2010). "Sandia National Laboratories: Energy Storage for the Electricity Grid: Benefits and Market Potential Assessment Guide" (PDF).
- "Huntington Digital Library - Monolith Substation".
- "Tehachapi, CA - Official Website | Official Website". www.liveuptehachapi.com. Retrieved 2020-05-13.
- Edison International. "SCE Unveils Largest Battery Energy Storage Project in North America". Edison International. Retrieved 2020-05-10.
- Wesoff, Eric. "The Biggest Battery in North America Gets Unveiled by SCE Today". www.greentechmedia.com. Retrieved 2020-05-10.
- Barnwell, Jack (September 23, 2014). "SCE to unveil major project on Sept. 24". Tehachapi News. Retrieved 2020-05-12.
- BakersfieldNow Staff (2014-09-23). "Large battery-energy storage project unveiled in Tehachapi". KBAK - BakersfieldNow - Channel 58. Retrieved 2020-05-11.
- Smirnoff, Nick. "Grand Opening of the Tehachapi Energy Storage Project". The Loop Newspaper. Retrieved 2020-05-12.
- Hull, Dana (2014-09-24). "Southern California Edison bets big on lithium ion for the nation's largest energy storage project". San Jose Mercury News: SiliconBeat. Retrieved 2020-05-14.
- Staff, S. I. (2014-09-25). "SCE Opens Tehachapi Energy Storage Project". Solar Industry. Retrieved 2020-05-12.
- "SoCal Edison opens 32 MWh battery energy storage project, largest in North America; batteries from LG Chem". Green Car Congress. September 24, 2014.
- "SCE Unveils Largest Battery Energy Storage Project in North America". T&D World News. October 8, 2014.
- Ayre, James (2014-09-28). "Tehachapi Energy Storage Project -- SoCal Edison Opens Largest Energy Storage Project In North America". CleanTechnica. Retrieved 2020-05-14.
- Van Burkleo, Jennifer (2014-09-25). "Largest battery energy storage in North America now operational". Power Engineering. Retrieved 2020-05-13.
- Lee, Bang-Sil (October 30, 2014). "North America's largest ESS for power generation ... Global Stage 'Turnkey Operator' Leadership". Dong-A Ilbo.
- Trabish, Herman (September 24, 2014). "SoCal Edison unveils largest battery storage system in U.S." Utility Dive.
- "Largest North America Battery Energy Storage System Opens". In Compliance Magazine. 2014-10-02. Retrieved 2020-05-16.
- "LG Chem operating energy storage system in California". Korea JoongAng Daily. September 25, 2014.
- "VIDEO: LG Chem switches on 32 MWh energy storage system in California". POWERGrid International. 2014-09-26. Retrieved 2020-05-13.
- "North America's Largest Battery Energy Storage System Now Operational". www.businesswire.com. 2014-09-24. Retrieved 2020-05-12.
- Loving, Bill. "SCE Unveils Largest Battery for Storing Electricity in North America". Energized by Edison. Retrieved 2020-05-10.
- McFerron, Whitney (October 14, 2014). "Giant Battery Unit Aims at Wind Storage Holy Grail: Commodities". Bloomberg.
- Pinsky, Naum; O'Neill, Lori (2017-03-31). "Tehachapi Wind Energy Storage Project - Technology Performance Report #3". U.S. Department of Energy – National Energy Technology Laboratory. doi: 10.2172/1349233.
- Gaillac, Loïc; Castaneda, Juan; Edris, Abdel-Aty; Elizondo, David; Wilkins, Carl; Vartanian, Charlie; Mendelsohn, David (May 2012). "Tehachapi Wind Energy Storage Project: Description of operational uses, system components, and testing plans". IEEE PES T&D 2012: 1–6. doi: 10.1109/TDC.2012.6281676.
- Business Roundtable (April 22, 2015). "Edison International" (PDF). Business Roundtable 2015 Sustainability Report: Create, Grow, Sustain: Leading By Example.
- "Energy Storage | Edison International". Southern California Edison. Retrieved 2020-05-10.
- Silverstein, Ken (2014-10-12). "Electric cars have batteries. Why not power plants?". Christian Science Monitor. ISSN 0882-7729. Retrieved 2020-05-16.
- Rittershausen, Johannes; McDonagh, Mariko. "Moving Energy Storage from Concept to Reality: Southern California Edison's Approach to Evaluating Energy Storage" (PDF). Southern California Edison.
- Muljadi, E.; Butterfield, C.P.; Yinger, R.; Romanowitz, H. (January 5–8, 2004). "Energy Storage and Reactive Power Compensator in a Large Wind Farm" (PDF). 42nd AIAA Aerospace Sciences Meeting and Exhibit.
- Strassel, Kim (March 26, 2015). "ECO:nomics: Developing Better Energy Storage". The Wall Street Journal.
- Editor, Claudia Elliott. "Now & Then: Remembering the quake of 1952". Tehachapi News. Retrieved 2020-05-17.CS1 maint: extra text: authors list ( link)
- "Kern County Earthquake". scedc.caltech.edu. Retrieved 2020-05-17.
- United States Earthquakes. U.S. Department of the Interior, Geological Survey. 1963.
- "United States Geological Survey (USGS) Earthquakes". earthquake.usgs.gov. Retrieved 2020-05-17.
- The Bakersfield Californian Media. "Highway 58 to remain closed at least through weekend". The Bakersfield Californian. Retrieved 2020-05-17.
- Czajka, Edward (October 17, 2015). "HWY58 Mudslide View from Drone".
- "Storm Watch: Hwy 58 still closed due to mudslide". ABC 23: KERO: Bakersfield. October 16, 2015.
- Southern California Edison. "California Public Utilities Commission: SCE Energy Storage Experience TSP & ISGD Program". California Public Utilities Commission.
- O'Neill, Lori (October 2012). "SCE tests one of the world's biggest batteries". Kern Business Journal October/November 2012 (posted at Issuu). Retrieved 2020-05-16.
- "Tehachapi Storage Project". Edison International: Newsroom.
- "Tehachapi Storage Project B-Roll". Edison International: Newsroom. Retrieved 2020-05-14.
- Bender, Donald; Byrne, Raymond; Borneo, Daniel (June 2015). "Sandia National Laboratories Report: ARRA Energy Storage Demonstration Projects: Lessons Learned and Recommendations" (PDF).
- McMahon, Richard; Infante, Lola (2017-05-22). "Harnessing the Potential of Energy Storage". Power Engineering. Retrieved 2020-05-10.
- Silverstein, Ken (April 21, 2017). "Energy Storage And Demand Response Propel California Forward On Earth Day". Forbes. Retrieved 2020-05-10.
- Nikolewski, Rob (2016-08-29). "Energy storage is taking on a greater role in the power grid. But how big can it get?". San Diego Union-Tribune. Retrieved 2020-05-14.
- Magill, Bobby (January 13, 2015). "California Takes Lead In Developing Energy Storage". Climate Central.
- Mora, Manuel Avendaño. "Energy Storage for Enhancing Grid Reliability" (PDF). University of California, Riverside: 2019 Energy Storage Technologies and Applications Conference.
- Yan, Joseph (March 12, 2015). "Reliability and Affordability: Challenges and Opportunities of Integrating Renewables" (PDF). Center for Ultra-Wide-Area Resilient Electric Energy Transmission Networks (CURRENT), a National Science Foundation (NSF) Engineering Research Center: Strategic Planning Meeting, March 12-13, 2015.
- Hart, David; Sarkissian, Alfred (June 2016). "Deployment of Grid-Scale Batteries in the United States" (PDF). George Mason University - Prepared for Office of Energy Policy and Systems Analysis - U.S. Department of Energy.
- Irwin, Mark (November 12, 2014). "Tehachapi Energy Storage Project (segment from The Future of Energy Storage)". Kern County Energy Summit 2014.
- "California ISO: Fast Facts: Large Scale Energy Storage Pilots" (PDF). 2014.
- Davis, Grant (September 21–24, 2015). "Tehachapi Wind Energy Storage Project" (PDF). U.S. DOE/OE Energy Storage Program Peer Review, EESAT 2015 Technical Conference.
- Irwin, Mark (November 12, 2014). "The Future of Energy Storage". Kern County Energy Summit 2014.
- Gaillac, Loic; Fok, Kevin (June 2014). "Tehachapi Wind Energy Storage Project | Energy Storage Association 24th Annual Conference". Energy Storage Association 24th Annual Conference. Retrieved 2020-05-13.
- Gaillac, Loic; Fok, Kevin (April 2015). "Energy Storage: New Capabilities for the Electric Grid – The Tehachapi Energy Storage Project". Next Generation Batteries 2015.
- "Preliminary Monthly Electric Generator Inventory (based on Form EIA-860M as a supplement to Form EIA-860)". United States Energy Information Administration. Retrieved 2020-05-24.
- "Batteries perform many different functions on the power grid - Today in Energy - U.S. Energy Information Administration (EIA)". www.eia.gov. Retrieved 2020-05-24.
- Wu, Fu-Bao; Yang, Bo; Ye, Ji-Lei, eds. (2019-01-01), "Chapter 6 - Application of energy storage technology in grid-connected new energy power generation", Grid-scale Energy Storage Systems and Applications, Academic Press, pp. 203–241, doi: 10.1016/b978-0-12-815292-8.00006-x, ISBN 978-0-12-815292-8, retrieved 2020-05-10
- Vadari, Mani,. Smart grid redefined : transformation of the electric utility. Boston. ISBN 978-1-63081-478-6. OCLC 1039931187.CS1 maint: extra punctuation ( link) CS1 maint: multiple names: authors list ( link)
- Ifill, Gwen; O'Brien, Miles (2015-12-15). "How building a better battery would change the game for renewable energy". PBS NewsHour. Retrieved 2020-05-14.
- California Independent System Operator (CAISO); Renewables Grid Initiative (October 2019). "Energy Storage: Perspectives from California and Europe, Discussion Paper – October 2019" (PDF). California Independent System Operator.
- "California ISO - Storage". California Independent System Operator. Retrieved 2020-05-13.
- Kristov, Lorenzo (March 17, 2017). "The Role of Energy Storage in the Future Electricity System". Presentation for Portuguese National Committee of CIGRE.
- Rollo, Jay; Sands, Marco. "Lessons from the Energy Storage Trenches". DISTRIBUTECH International 2020. Retrieved 2020-05-10.
- Enslin, Johan; Fok, Kevin. "Energy Storage Experiences in California". DISTRIBUTECH International 2020. Retrieved 2020-05-12.
- Breslau, Lindsay; Croweak, Michael; Witt, Alan (2017-10-24). "Batteries Included: Incentivizing Energy Storage". Sustainable Development Law & Policy. 17 (2).
- Byrne, Raymond H.; Nguyen, Tu A.; Copp, David A.; Chalamala, Babu R.; Gyuk, Imre (2018). "Energy Management and Optimization Methods for Grid Energy Storage Systems". IEEE Access. 6: 13231–13260. doi: 10.1109/ACCESS.2017.2741578. ISSN 2169-3536.
- Yu, Nanpeng (May 3–5, 2016). "Stochastic Valuation of Energy Storage Systems" (PDF). IEEE/PES Transmission and Distribution Conference and Exposition.CS1 maint: date format ( link)
- Yu, Nanpeng; Foggo, Brandon (March 18, 2017). "Stochastic valuation of energy storage in wholesale power markets" (PDF). Energy Economics. 64 (2017): 177–185.
- Mohsenian-Rad, Hamed (January 2016). "Optimal Bidding, Scheduling, and Deployment of Battery Systems in California Day-Ahead Energy Market". IEEE Transactions on Power Systems. 31 (1): 442–453. doi: 10.1109/TPWRS.2015.2394355. ISSN 0885-8950.
- Mohsenian-Rad, Hamed (January 2016). "Coordinated Price-Maker Operation of Large Energy Storage Units in Nodal Energy Markets". IEEE Transactions on Power Systems. 31 (1): 786–797. doi: 10.1109/TPWRS.2015.2411556. ISSN 0885-8950.
- Edison Electric Institute (October 2018). "U.S. Electric Company Investment and Innovation in Energy Storage" (PDF). Edison Electric Institute.
- Schledde, Dominik (August 15, 2018). "Support to R&D Strategy for battery based energy storage: Technical analysis of ongoing projects (D12)" (PDF). European Commission Directorate General Energy.
- "Ribbon-Cutting for Southern California Edison Tehachapi Energy Storage Project". From Edison International: Energy Storage. September 24, 2014.
- "Energy Storage North America 2014 Post-Show Report". Energy Storage North America 2014 Post-Show Report. Retrieved 2020-05-15.
- "Energy Storage North America Hall of Fame". Energy Storage North America. Retrieved 2020-05-15.
- "2018 Economic Round Table Report" (PDF). Greater Antelope Valley Economic Alliance. 2018.
- "2019 Economic Round Table Report" (PDF). Greater Antelope Valley Economic Alliance. 2019.
- Meredith, Kasey. "KEDC's Economic Summit highlights Kern's best assets". The Bakersfield Californian. Retrieved 2020-05-14.
- "Market Overview". Kern Economic Development Corporation. 2019–2020. Retrieved 2020-05-10.CS1 maint: date format ( link)
- Jackson, Cara. "What's up in town? Art, hospital news and economic growth tackled at EDC meeting". Tehachapi News. Retrieved 2020-05-23.
- U.S. Department of Energy Office of Technology Transitions (July 2019). "Solving Challenges in Energy Storage" (PDF).