October 15, 2012 PV & Storage Workshop PV and Storage Integration strawman proposals & discussion John Adams Principal Engineer

2 Tab X ERCOT Public/Confidential/Restr icted Inverter based technologies to provide: PSS/E dynamic model for the inverter with associated parameters. PSCAD dynamic model for the inverter with associated parameters Expected fault characteristics of the inverter with full energy available. Full Interconnection Studies (FIS) shall include three phase fault at Point of Interconnect (POI) with which ERCOT can analyze voltage ride-through. Inverters are to provide 95% of reactive requirement within 0.5 seconds after a step voltage change from 100% of nominal to 90% of nominal. Full Interconnection Studies (FIS) shall demonstrate that voltage recovery after a fault is dampened within 6 seconds of the end of the event.

3 Tab X ERCOT Public/Confidential/Restr icted Photovoltaic technologies to provide: To accommodate solar energy forecasts fixed position solar farms shall provide ERCOT their latitude, longitude, alignment of solar panels, and placement angle off horizontal. Solar farms of over 100 MW capacities shall supply Total Sky Imager (1) and transfer sky images to ERCOT once every 30 seconds to facilitate short term cloud impact on energy production. Metrologic data at 30 second intervals as follows: Air temperature Back of panel temperature Wind speed Wind direction Global horizontal Irradiance For concentrated PV installations, in addition to the above, direct normal Irradiance shall be telemetered. (1) From “Benefits of Near-Term Cloud Location Forecasting for Large Solar PV”, a Thesis presented to the Faculty of California Polytechnic State University by Timothy Robert Rudd, August 2011.

4 Tab X ERCOT Public/Confidential/Restr icted Storage based to provide: Registration of maximum MW delivery capability Registration of maximum MWH capacity Registration of maximum MW charge rate. Registration of Transition time from Charging => Discharge and Discharge => Charge Telemeter current available power capability (MW) Telemeter current available energy availability (MWH) Telemeter maximum rate of power delivery or charging change (dP/dt) (MW/minute – telemetry represents delivery if current state is delivering power, and charging if current state is charging) Telemeter status including new statuses: Charging, On_reg_Charging, On_NS_Charging. Telemeter transition time from current state (Charging or Discharging) to other state (Discharging or Charging)

Discussion?