HYBRID HYDROPOWER-STORAGE UNITS FOR GREATER OPERATIONAL FLEXIBILITY THE PROPOSED RESEARCH IS TO INVESTIGATE THE AUGMENTATION OF STANDARD HYDROELECTRIC GENERATION UNITSWITH FAST-ACTING ENERGY STORAGE TO CREATE A HYBRID HYDROELECTRIC GENERATION UNIT, WHICH WILL BE CAPABLE OF FASTER RESPONSE, GREATER VOLTAGE AND REACTIVE POWER SUPPORT, AND GREATER FREQUENCY REGULATION FOR ACCOMMODATING LARGER PENETRATIONS OF RENEWABLES AND MODERN INVERTER-BASED LOADS ON THE GRID. THIS PROJECT PROPOSES THE CONSTRUCTION OF A 200 KW LAB-BASED HYBRID HYDROELECTRIC GENERATION UNIT THAT WILL SERVE AS A TESTBED FOR PERFORMANCE ANALYSIS AND MODEL VALIDATION. ONCE THE MODEL IS VALIDATED, IT WILL BE INTEGRATED INTO A HIGH-RESOLUTION REAL-TIME WIDE-AREA GRID MODEL TO INVESTIGATE THE BENEFITS AND ISSUES ARISING FROM LARGE-SCALE INTEGRATION OF HYBRID UNITS. THE LAB-BASED TESTBED WILL BE USED TO INVESTIGATE SYSTEM PERFORMANCE, AND FOR MODEL VALIDATION. THE MODELS WILL THEN BE USED IN A TRANSIENT HIGH-RESOLUTION MODEL OF THE WESTERN INTERCONNECT UNDER SEVERAL TEST-CONDITIONS: THE SUDDEN LOSS OF LARGE-SCALE GENERATION TO TEST SYSTEM FREQUENCY RESPONSE AND RECOVERY, AND SCENARIOS WITH LARGE-SCALE PENETRATION OF WIND AND SOLAR, ESPECIALLY WITH LARGESCALE SOLAR ON PARTLY-CLOUDY DAYS, IN WHICH CONDITIONS CAUSE LARGE AND FAST FLUCTUATIONS IN POWER. A COMPREHENSIVE TECHNO-ECONOMIC ANALYSIS AND MARKET PLAN DEVELOPMENT WILL QUANTIFY COSTS AND BENEFITS, AND ILLUMINATE PATHS TO MARKET AND IMPLEMENTATION OF THE PROJECT OUTCOMES.