Photovoltaic Environmental Performance and Reliability (PEPER) Project Objectives: Monitor performance of grid-tied PV systems Report Energy Yields and Degradation Rates Evaluate new PV system technologies Principal Investigator for Part 1: Alex Cronin Students: Adria Brooks, Tucker Bundgard, Alex Hickey, Daniel Cormode, Deanna Lewis, Nick Davidson, Ryan Price, Vincent Lonij, Steve Pulver Collaborators: Tucson Electric Power, AZRISE, Biosphere 2, SOLON Corporation, NREL, University of Arizona Graduate College, Science Foundation Arizona, NASA Space Grant Consortium

TEP PV test yard 4350 E. Irvington Rd.

utility grade AC kwh meter and custom DC current and voltage monitors

Sunpower system DC current and voltage monitors

Data loggers from JK microsystems

Tours: we’ve had over 1,500 visitors since 2009, And given public lectures to over 6,000 people

AC Output every minute shown for 2 days: Data on-line at:

Daily output from a 1.5 kW PV system Y f = 5.3 h/day = 1935 h/yr Y f = “final yield” is defined in IEC standard

TF

Comparison of final yields in 6 places

Degradation Rates for 20 PV systems Steve Pulver, Daniel Cormode, Alex Cronin, Dirk Jordan, Sarah Kurtz, Ryan Smith, “Measuring Degradation Rates Without Irradiance Data”, 35th IEEE Photovoltaics Specialists Conference, Honolulu, HI (2010). Reference:

Temperature and DC Voltage

DC Voltage vs Temperature

Measured Efficiency for 9 systems

Niket Thakkar, Alex Cronin, Daniel Cormode, Vincent Lonij, “A Simple Nonlinear Model for the Effect of Partial Shade”, 35th IEEE Photovoltaics Specialists Conference, Honolulu, HI (2010). Reference: Mutual Shading  Large de-rating

S1 S2 model S1 S2 model Niket Thakkar, Alex Cronin, Daniel Cormode, Vincent Lonij, “A Simple Nonlinear Model for the Effect of Partial Shade”, 35th IEEE Photovoltaics Specialists Conference, Honolulu, HI (2010). Reference:

S1 S2 model Niket Thakkar, Alex Cronin, Daniel Cormode, Vincent Lonij, “A Simple Nonlinear Model for the Effect of Partial Shade”, 35th IEEE Photovoltaics Specialists Conference, Honolulu, HI (2010). Reference:

Niket Thakkar, Alex Cronin, Daniel Cormode, Vincent Lonij, “A Simple Nonlinear Model for the Effect of Partial Shade”, 35th IEEE Photovoltaics Specialists Conference, Honolulu, HI (2010). Reference: Extrapolations using our non-linear model of mutual shading. Shade de-rating Optimized kwh/acre

Heuristic for mutual shading: get a clear view of the sky from the bottom of each module.

Plans Publish yield and efficiency statistics for PV models Evaluate PV Performance Models: CEC 5-parameter model Sandia / King Model PVsyst / PVUSA SAM (NREL) Model Collaborate more with NREL, SANDIA, SunPower, Semprius, SolFocus, Solindra, SOLON, Global Solar, TEP and Biosphere2

Photovoltaic Environmental Performance and Reliability (PEPER) Project Objectives: Monitor performance of grid-tied PV systems Report Energy Yields and Degradation Rates Evaluate new PV system technologies Principal Investigator for Part 1: Alex Cronin Students: Adria Brooks, Tucker Bundgard, Alex Hickey, Daniel Cormode, Deanna Lewis, Nick Davidson, Ryan Price, Vincent Lonij, Steve Pulver Collaborators: Tucson Electric Power, AZRISE, Biosphere 2, SOLON Corporation, NREL, University of Arizona Graduate College, Science Foundation Arizona, NASA Space Grant Consortium

Photovoltaic Environmental Performance and Reliability (PEPER) Project Objectives: High-quality Irradiance data Atmospheric Science and Power Forecasting Principal Investigator for Part 2: Bill Conant Students: Anna Woschuitz Collaborators: Tucson Electric Power, NREL

Photovoltaic Environmental Performance and Reliability (PEPER) Project Objectives: Develop an accurate temperature measurement system for monitoring modules at the TEP Yard; Evaluate the performance of TF and concentrator modules at TEP Principal Investigator for Part 3: Raymond K. Kostuk, Jose Castro Students: Derek Zhang Collaborators: Prism Solar Technologies, Global Solar

Comparison of Temperature Sensors Thermocouple: A junction of two different metals which produce a voltage related to the temperature of the junction. Currently at TEP Useful range: −200 °C to °C Thermistor: Generally made of ceramic or polymers, the resistance varies with temperature Useful range: −90 °C to 130 °C Greater precision

Thermistor on GSE 45W modules

Thermistor Temperature Measurement Vs (+5V) High precision, low temperature coefficient resistor: Rc Vout

Concentration Test Setup Xenon Arc Lamp Collimating Lens Homogenizing Optics PV Cell Under Test Solar simulator: 300W Xenon-arc lamp with AM1.5 filter Flash I-V curve obtained with source meter Temperature is maintained at 25 ˚ C Irradiance referenced with calibrated silicon detectors Irradiance Distribution on PV Cell Concentrating Lens

Concentration Test Results

Plans Use Global Solar Cells with Prism Concentrators Maximize yields by harnessing efficiency non-linearities UA Students working at Global Solar and Prism Solar Tech. Calibrate thermistor sensors for high accuracy temperature measurements;