Demonstration of Essential Reliability Services by a 300-MW Solar
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Demonstration of Essential Reliability Services by a 300-MW Solar Photovoltaic Power Plant Clyde Loutan, Peter Klauer, Sirajul Chowdhury, and Stephen Hall California Independent System Operator Mahesh Morjaria, Vladimir Chadliev, Nick Milam, and Christopher Milan First Solar Vahan Gevorgian National Renewable Energy Laboratory NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Technical Report NREL/TP-5D00-67799 March 2017 Contract No. DE-AC36-08GO28308 Demonstration of Essential Reliability Services by a 300- MW Solar Photovoltaic Power Plant Clyde Loutan, Peter Klauer, Sirajul Chowdhury, and Stephen Hall California Independent System Operator Mahesh Morjaria, Vladimir Chadliev, Nick Milam, and Christopher Milan First Solar Vahan Gevorgian National Renewable Energy Laboratory Prepared under Task No. ST6S.1010 NREL is a national laboratory of the U.S. Department of Energy Office of Energy Efficiency & Renewable Energy Operated by the Alliance for Sustainable Energy, LLC This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. National Renewable Energy Laboratory Technical Report 15013 Denver West Parkway NREL/TP-5D00-67799 Golden, CO 80401 March 2017 303-275-3000 • www.nrel.gov Contract No. DE-AC36-08GO28308 NOTICE This report was prepared as an account of work sponsored by an agency of the United States government. Neither the United States government nor any agency thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States government or any agency thereof. This report is available at no cost from the National Renewable Energy Laboratory (NREL) at www.nrel.gov/publications. Available electronically at SciTech Connect http:/www.osti.gov/scitech Available for a processing fee to U.S. Department of Energy and its contractors, in paper, from: U.S. Department of Energy Office of Scientific and Technical Information P.O. Box 62 Oak Ridge, TN 37831-0062 OSTI http://www.osti.gov Phone: 865.576.8401 Fax: 865.576.5728 Email: [email protected] Available for sale to the public, in paper, from: U.S. Department of Commerce National Technical Information Service 5301 Shawnee Road Alexandria, VA 22312 NTIS http://www.ntis.gov Phone: 800.553.6847 or 703.605.6000 Fax: 703.605.6900 Email: [email protected] Cover Photos by Dennis Schroeder: (left to right) NREL 26173, NREL 18302, NREL 19758, NREL 29642, NREL 19795. NREL prints on paper that contains recycled content. Acknowledgments We thank and acknowledge the substantial contributions to this work provided by the staff of First Solar’s corporate office, located in Tempe, Arizona, during the planning and implementation stages of this project. The authors also thank Dr. Guohui Yuan of the U.S. Department of Energy’s Solar Energy Technologies Office for his continuous support of this project. iii This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications. List of Acronyms ACE Area control error AGC Automatic generation control APC Active power control BAAL Balancing Authority ACE Limit BA Balancing authority CAISO California Independent System Operator FERC Federal Energy Regulatory Commission FFR Fast frequency response NERC North American Electric Reliability Corporation NREL National Renewable Energy Laboratory PFR Primary frequency response POI Point of interconnection PPC Power plant controller PV Photovoltaic ROCOF Rate of change of frequency RPS Renewable portfolio standard SCADA Supervisory Control and Data Acquisition iv This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications. Executive Summary The California Independent System Operator (CAISO), First Solar, and the National Renewable Energy Laboratory (NREL) conducted a demonstration project on a large utility-scale photovoltaic (PV) power plant in California to test its ability to provide essential ancillary services to the electric grid. With increasing shares of solar- and wind-generated energy on the electric grid, traditional generation resources equipped with automatic governor control (AGC) and automatic voltage regulation controls—specifically, fossil thermal—are being displaced. The deployment of utility-scale, grid-friendly PV power plants that incorporate advanced capabilities to support grid stability and reliability is essential for the large-scale integration of PV generation into the electric power grid, among other technical requirements. A typical PV power plant consists of multiple power electronic inverters and can contribute to grid stability and reliability through sophisticated “grid-friendly” controls. In this way, PV power plants can be used to mitigate the impact of variability on the grid, a role typically reserved for conventional generators. In August 2016, testing was completed on First Solar’s 300-MW PV power plant, and a large amount of test data was produced and analyzed that demonstrates the ability of PV power plants to use grid-friendly controls to provide essential reliability services. These data showed how the development of advanced power controls can enable PV to become a provider of a wide range of grid services, including spinning reserves, load following, voltage support, ramping, frequency response, variability smoothing, and frequency regulation to power quality. Specifically, the tests conducted included various forms of active power control such as AGC and frequency regulation; droop response; and reactive power, voltage, and power factor controls. This project demonstrated that advanced power electronics and solar generation can be controlled to contribute to system-wide reliability. It was shown that the First Solar plant can provide essential reliability services related to different forms of active and reactive power controls, including plant participation in AGC, primary frequency control, ramp rate control, and voltage regulation. For AGC participation in particular, by comparing the PV plant testing results to the typical performance of individual conventional technologies, we showed that regulation accuracy by the PV plant is 24–30 points better than fast gas turbine technologies. The plant’s ability to provide volt-ampere reactive control during periods of extremely low power generation was demonstrated as well. The project team developed a pioneering demonstration concept and test plan to show how various types of active and reactive power controls can leverage PV generation’s value from being a simple variable energy resource to a resource that provides a wide range of ancillary services. With this project’s approach to a holistic demonstration on an actual, large, utility- scale, operational PV power plant and dissemination of the obtained results, the team sought to close some gaps in perspectives that exist among various stakeholders in California and nationwide by providing real test data. v This report is available at no cost from the National Renewable Energy Laboratory at www.nrel.gov/publications. Table of Contents 1 Introduction ........................................................................................................................................... 1 2 PV Power Plant Description ................................................................................................................ 9 3 AGC Participation Tests for First Solar’s 300-MW PV Power Plant .............................................. 13 3.1 Description and Rationale for AGC Tests ................................................................................... 13 3.2 AGC Test Results ........................................................................................................................ 15 4 Frequency Droop Control Tests ........................................................................................................ 23 4.1 Rationale and Description of Frequency Droop Tests ................................................................ 23 4.2 Droop Test Results ...................................................................................................................... 25 4.2.1 Droop Tests during Underfrequency Event .................................................................... 25 4.2.2 Frequency Droop Tests during Overfrequency Event .................................................... 31 5 Reactive Power and Voltage Control Tests ..................................................................................... 34 5.1 Rationale and Description of Reactive Power Tests ................................................................... 34 5.2 Results of Reactive Capability Power Tests ...............................................................................