Solar Electricity Production from Fixed-Inclined and Sun-Tracking - PowerPoint PPT Presentation

Solar Electricity Production from Fixed-Inclined and Sun-Tracking c-Si Photovoltaic Modules Marcel Š úri in South Africa Tomá š Cebecauer Artur Skoczek Juraj Beták GeoModel Solar s.r.o http://geomodel.eu Bratislava, Slovakia SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [1]

About GeoModel Solar Expert consultancy • Solar resource assessment and meteo databases • PV yield assessment and performance modeling Development and operation of SolarGIS meteo database and real-time data services for: • Site selection and prefeasibility • Planning and project design • Monitoring and forecasting of solar power 20+ years on geoinformatics, 12 years in solar energy and PV http://geomodelsolar.eu SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [2]

Timeline 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 PVGIS SolarGIS Research and demonstration project Commercial database, Promotion of PV Professional software Public awareness in Europe Industrial applications by European Commission, by GeoModel Solar Joint Research Centre SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [3]

Contents 1. Introduction 2. Data • Solar radiation • Air temperature 3. PV simulation methods 4. Results • Fixed mounting at optimum angle • c-Si vs. thin films • One axis tracking options • Two axis tracking • Optimisations 5. Conclusions SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [4]

Sun-trackers vs. fixed mounting Fixed mounting: • Very robust, low risk • Optimum tilt: one angle or two (seasonal) angles • Low investment and maintenance • c-Si vs. thin films Sun-tracking: • High performance PV modules – options: • 1-axis: horizontal (NS, EW), vertical, inclined axis • 2-axis • Higher yields • Higher investment and maintenance costs • Optimization necessary Question: is it feasible/profitable to consider suntrackers in South Africa? SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [5]

Contents 1. Introduction 2. Data • Solar radiation • Air temperature 3. PV simulation methods 4. Results • Fixed mounting at optimum angle • c-Si vs. thin films • One axis tracking options • Two axis tracking • Optimisation 5. Conclusions SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [6]

Solar radiation – sources of information 1. Ground sensors • Pyranometers or photo cells • Installed on the site 2. Solar radiation models • Input: satellite & atmospheric data • Data are available globally SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [7]

Option 1: Ground (on-site) measurements ADVANTAGES LIMITATIONS High frequency measurements (sec. to min.) Sensor accuracy Higher accuracy, if properly managed and Need of regular maintenance and calibration controlled Data cleaning and management High costs for acquisition and operation Motivated personnel Quality has to be systematically guaranteed SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [8]

Errors in ground measurements Quality-control procedures Missing data Time shifts Unrealistic values Shading Misaligned and miscalibrated sensors SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [9]

Option 2: Solar models using satellite data ADVANTAGES LIMITATIONS Available everywhere (continuous coverage) Lower instantaneous accuracy for the point estimate (when compared to high Spatial resolution app. 4 x 4 km in South Africa quality ground measurements) Frequency of measurements 15 minutes Spatial and temporal consistency Calibration stability Availability ~99% History 18+ years Continuous and global geographical coverage Data sources: NOAA, ECMWF SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [10]

Resolution of the input data used in the SolarGIS model AOD: Atmospheric Optical Depth WV: Water Vapour MFG/MSG: Meteosat First/Second Generation Satellite-derived data capture regional details SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [11]

Typical uncertainty of ground-measured and satellite-derived solar data in Central Europe Global Horizontal Irradiation Pyranometers and photo cells Satellite ISO Classification Secondary Standard First Class Second Class WMO Classification High Quality Good Quality Mod. Quality RMSD hourly 3% 8% 20% 9-20% RMSD daily 2% 5% 10% 4-12% BIAS 1-3% (systematic deviation) ±2-3% bias depends on calibration and maintenance RMSD = Root Mean Square Deviation Bias: • Is natural for satellite-derived data and can be reduced/removed • It is challenging and costly to keep quality ground measurements at high standard This uncertainty for ground sensors can only be considred on condition of systematic and qualified maintenance of sensors, continuous operation, calibration and data quality control. SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [12]

Comparison of satellite and ground measured data Compared to ground measurements - satellite data : Uncertainty is higher for: • Lower resolution (area 4x4 km) • Variable cloudiness • Time step is 15 minutes (Meteosat MSG) • Low-light conditions • Low sun angle SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [13]

Air temperature Derived from NOAA NCEP GFS and CFSR models § Data available from 01/1994 up to present § Original resolution of 1 and 6 hours is interpolated to hourly or 15-minute values § Original grid cell resolution of 0.25 arc-degrees is post-processed to 1 km Air temperature SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [14]

Contents 1. Introduction 2. Data • Solar radiation • Air temperature and other data 3. PV simulation methods 4. Results • Fixed mounting at optimum angle • c-Si vs. thin films • One-axis tracking options • Two axis tracking • Optimisations 5. Conclusions SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [15]

Performance under STC (Standard Test Conditions): 1429 kWh/kWp Global irradiation Air temperature PV simulation models (module surface) Shading by terrain -0.0% Angular reflection -3.1% Performance outside -8.5% STC DC losses -6.5% ±2.5% -2.5% ±0.5% Inverters -1.0% ±0.5% AC and transformers -10.0% ±2.5% Availability -0.5% ±0.5% DC losses: mismatch, cabling, dirt, dust, snow, icing, self-shading, Output: 1141 kWh/kWp Simulations for a variety of PV modules (c-Si, CIS/CIGS, a-Si, … ) Simulations for fixed and tracking systems SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [16]

Simulation of c-Si and a-Si modules Energy yield and performance ratio Effectiveness Triple junction roof-integrated PR a-Si modules mounted horizontally Air temperature Free-standing c-Si modules mounted horizontally Air temprature and PR: Red: measured data (SUPSI) Black: simulated data (SolarGIS ) In collaboration with SUPSI DAADC ISAAC Lugano, Switzerland (Skoczek et al. 2011) ! SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [17]

Contents 1. Introduction 2. Data • Solar radiation • Air temperature and other 3. PV simulation methods 4. Results • Fixed mounting at optimum angle • c-Si vs. thin films • One-axis tracking options • Two axis tracking • Optimisation 5. Conclusions SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [18]

Base case: fixed mounting at optimum angle Optimum tilt: 24° to 36° Maximization of annual yield SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [19]

Base case: fixed mounting at optimum angle Optimum tilt: 24° to 36° Maximization of annual yield Optimum tilt: 22° to 34° if 0.5% annual losses allowed SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [20]

Annual yield: fixed mounting at an optimum tilt Annual energy yield of a PV system: 1500 to 2000 kWh/kWp c-Si modules SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [21]

Fixed mounting at an optimum angle Annual energy yield of a PV system: 1500 to 2000 kWh/kWp c-Si modules SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [22]

Fixed mounting: PV module technologies c-Si vs. thin films ¡ ¡ Durban ¡ Cape ¡Town ¡ Sasolburg ¡ Kimberley ¡ Upington ¡ Aggeneys ¡ c-­‑Si ¡ 1442 ¡ 1687 ¡ 1815 ¡ 1878 ¡ 1944 ¡ 1999 ¡ CIS/CIGS ¡ +1% ¡to ¡2% ¡ +1% ¡to ¡2% ¡ +1% ¡to ¡2% ¡ +1% ¡to ¡2% ¡ +1% ¡to ¡2% ¡ +1% ¡to ¡2% ¡ a-­‑Si ¡ +4% ¡to ¡7% ¡ +3% ¡to ¡5% ¡ +7% ¡to ¡9% ¡ +8% ¡to ¡10% ¡ +8% ¡to ¡10% ¡ +8% ¡to ¡10% ¡ SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [23]

Fixed mounting: one optimum angle vs. two seasonal angles ¡ ¡ Durban ¡ Cape ¡Town ¡ Sasolburg ¡ Kimberley ¡ Upington ¡ Aggeneys ¡ one ¡op>mum ¡ angle ¡ 1442 ¡ 1687 ¡ 1815 ¡ 1878 ¡ 1944 ¡ 1999 ¡ two ¡seasonal ¡ angles ¡ +2.9% ¡ +2.8% ¡ +3.8% ¡ +4.0% ¡ +4.0% ¡ +4.0% ¡ c-Si modules SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [24]