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

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

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Solar Electricity Production from Fixed-Inclined and Sun-Tracking c-Si Photovoltaic Modules Marcel ri in South Africa Tom Cebecauer Artur Skoczek Juraj Betk GeoModel Solar s.r.o http://geomodel.eu Bratislava, Slovakia SASEC

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [1]

http://geomodel.eu

Solar Electricity Production from Fixed-Inclined and Sun-Tracking c-Si Photovoltaic Modules in South Africa

Marcel Šúri Tomáš Cebecauer Artur Skoczek Juraj Beták GeoModel Solar s.r.o Bratislava, Slovakia

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [2]

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

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [3]

PVGIS

Research and demonstration project Promotion of PV Public awareness in Europe by European Commission, Joint Research Centre

SolarGIS

Commercial database, Professional software Industrial applications by GeoModel Solar 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011

Timeline

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SLIDE 4

SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [4]

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
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [5]

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?

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [6]

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
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [7]

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
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [8]

Option 1: Ground (on-site) measurements

ADVANTAGES LIMITATIONS High frequency measurements (sec. to min.) Higher accuracy, if properly managed and controlled Sensor accuracy Need of regular maintenance and calibration Data cleaning and management High costs for acquisition and operation Motivated personnel Quality has to be systematically guaranteed

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [9]

Errors in ground measurements

Quality-control procedures Missing data Time shifts Unrealistic values Shading Misaligned and miscalibrated sensors

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [10]

Option 2: Solar models using satellite data

ADVANTAGES LIMITATIONS Available everywhere (continuous coverage) Spatial resolution app. 4 x 4 km in South Africa Frequency of measurements 15 minutes Spatial and temporal consistency Calibration stability Availability ~99% History 18+ years Continuous and global geographical coverage Lower instantaneous accuracy for the point estimate (when compared to high quality ground measurements)

Data sources: NOAA, ECMWF

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [11]

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

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [12]

Typical uncertainty of ground-measured and satellite-derived solar data in Central Europe

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 (systematic deviation) 1-3% bias depends on calibration and maintenance ±2-3%

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.

Global Horizontal Irradiation

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [13]

Compared to ground measurements - satellite data:

  • Lower resolution (area 4x4 km)
  • Time step is 15 minutes (Meteosat MSG)

Comparison of satellite and ground measured data

Uncertainty is higher for:

  • Variable cloudiness
  • Low-light conditions
  • Low sun angle
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [14]

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

Air temperature

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [15]

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
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [16]

Global irradiation (module surface) Air temperature Inverters DC losses Angular reflection Shading by terrain Performance outside STC AC and transformers Availability

Performance under STC (Standard Test Conditions): 1429 kWh/kWp

  • 0.0%
  • 8.5%
  • 3.1%
  • 6.5% ±2.5%
  • 2.5% ±0.5%
  • 1.0% ±0.5%
  • 0.5% ±0.5%
  • 10.0% ±2.5%

Output: 1141 kWh/kWp

DC losses: mismatch, cabling, dirt, dust, snow, icing, self-shading, Simulations for a variety of PV modules (c-Si, CIS/CIGS, a-Si, …) Simulations for fixed and tracking systems

PV simulation models

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [17]

Simulation of c-Si and a-Si modules Energy yield and performance ratio

Air temprature and PR: Red: measured data (SUPSI) Black: simulated data (SolarGIS ) In collaboration with SUPSI DAADC ISAAC Lugano, Switzerland (Skoczek et al. 2011)

Triple junction roof-integrated a-Si modules mounted horizontally Free-standing c-Si modules mounted horizontally

!

PR Air temperature Effectiveness

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [18]

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
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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

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [20]

Optimum tilt: 24° to 36° Maximization of annual yield

Optimum tilt: 22° to 34° if 0.5% annual losses allowed

Base case: fixed mounting at optimum angle

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [21]

Annual yield: fixed mounting at an optimum tilt

Annual energy yield

  • f a PV system:

1500 to 2000 kWh/kWp c-Si modules

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [22]

Fixed mounting at an optimum angle

Annual energy yield

  • f a PV system:

1500 to 2000 kWh/kWp c-Si modules

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [23]

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% ¡

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [24]

Fixed mounting: one optimum angle

  • vs. two seasonal angles

¡ ¡ Durban ¡ Cape ¡Town ¡ Sasolburg ¡ Kimberley ¡ Upington ¡ Aggeneys ¡

  • ne ¡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

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [25]

Comparison of 1-axis and 2-axis tracking strategies

Durban Cape Town Sasolburg Kimberley Upington Aggeneys Fixed mounting, optimum 1442 1687 1815 1878 1944 1999 1 axis horizontal EW 2% 4% 3% 4% 4% 5% 1 axis horizontal NS 12% 23% 20% 23% 24% 26% 1 axis vertical 48 deg 20% 30% 26% 31% 31% 32% 1 axis inclined NS 30 deg 20% 30% 28% 31% 32% 34% 2 axis tracker 24% 34% 32% 36% 36% 39%

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [26]

One-axis tracking with North-tilted axis at 30 degrees

Gain in annual energy yield compared to fixed mounting: 20% to 35%

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [27]

Two-axis tracking

Gain in annual energy yield compared to fixed mounting: 25% to 40% About 4% more, compared to 1-aixs tracker with inclined axis

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [28]

Comparison 1-axis inclined vs. 2 axis trackers

Durban Cape Town Sasolburg Kimberley Upington Aggeneys Fixed mounting,

  • ptimum tilt

1442 kWh/kWp 1687 kWh/kWp 1815 kWh/kWp 1878 kWh/kWp 1944 kWh/kWp 1999 kWh/kWp Annual diffuse/global horizontal irradiation 44% 32% 33% 27% 26% 22% 1-axis tracker inclined at 30° +20% +30% +28% +31% +32% +34% 2 axis tracker +24% +34% +32% +36% +36% +39%

Table 1. Gain in PV electricity production for 1 axis and 2 axis tracker, when compared

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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [29]

What needs to be considered

  • Optimization of trackers field
  • Terrain
  • Minimizing self-shading
  • Optimization of moving behavior
  • Limitation of rotation axis
  • Backtracking
  • Intelligent tracking (forecasting)
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SLIDE 30

SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [30]

Contents

  • 1. Introduction
  • 2. Data
  • Solar radiation
  • Air temperature and other
  • 3. PV simulation methods
  • 4. Results
  • Fixed mounting
  • c-Si vs. thin films
  • One-axis tracking options
  • Two axis tracking
  • Optimisation
  • 5. Conclusions
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SASEC 2012, Stellenbosch, South Africa, 21-23 May 2012 [31]

Gain of tracking options (compared to fixed mounting optimum angle):

  • One-axis tracking:
  • horizontal East-West axis: +2 to 5%
  • horizontal North-South axis: +12 to 26%
  • vertical axis: 20 to 32%
  • inclined axis: 20 to 34%
  • Two axis tracking: +24 to 39%

For trackers: optimization needed! Gain from 2 seasonal angles: +3 to 4% How thin films compare to c-Si:

  • a-Si: +4 to 10%
  • CIS/CIGS: +1 to 2%

Conclusions

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