ercot solar modeling – etwg meeting
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ERCOT Solar Modeling – ETWG Meeting. April 30, 2013. Project Overview. Objective : Produce 20 years of high-quality hourly solar production data for several different solar technologies in all 254 Texas counties - PowerPoint PPT PresentationTRANSCRIPT
ERCOT Solar Modeling – ETWG Meeting
April 30, 2013
Project Overview
▫ Objective: Produce 20 years of high-quality hourly solar production data for several different solar technologies in all 254 Texas counties
▫ Methodology: Utilize National Solar Radiation Database (NSRDB) Class I and Class II weather station data and solar production modeling software to generate 4,452 individual datasets with 8,760 points each
Agenda
▫ Origin and quality of raw data▫ How solar production modeling software
works▫ Weather station-county grouping▫ Summary of results▫ Quality assurance and statistical analysis▫ Q&A
Project Overview
Project Overview
Task 1: Collect Data
Meteorological Data Required for Solar Simulations
Entry UnitsDry-bulb temperature °CDew-point temperature °CRelative humidity %Wind speed m/sWind direction degAtmospheric pressure mbarGlobal horizontal radiation W/m²Direct normal radiation W/m²Diffuse horizontal radiation W/m²
System Advisory Model (SAM) Weather Data Documentation- 12/7/2011
National Solar Radiation Database (NSRDB)
▫ 20 years (1991-2010) of measured/modeled solar radiation data with accompanying meteorological fields for weather stations across the US
▫ Solar radiation data generated by the NREL Meteorological-Statistical Model (METSTAT) and a State University of New York (SUNY) developed model based on satellite data
▫ Weather data from National Climate Data Center (NCDC)
NSRDB
▫ Four levels of data-filling methods– Short-term interpolation - up to 5 hour gaps and
gaps at night – Medium-term filling - gaps up to 24 hours– Long-term filling - gaps up to 1 year– Last-ditch filling - gaps greater than a year– Level of data filling required determines Class of
weather station
NSRDB▫ Class I Stations
– Complete period of record (all hours 1991–2010) for solar and key meteorological fields
– Highest-quality solar modeled data (16 sites in Texas)
▫ Class II Stations– Complete period of record but significant periods of
interpolated, filled, or otherwise lower-quality input data for the solar models (37 in Texas).
▫ Class III Stations– Have some gaps in the period of record but have at least 3 years
of data that might be useful for some applications (36 in Texas)
National Solar Radiation Database (NSRDB) 1991-2010 User’s Manual
Class I / II Weather Stations in TX
Red = Class I White = Class II
URS GIS Dept.
53 Class I/II NSRDB Weather Stations in TX
NSRDB Meteorological Data•20 years (1991-2010) of hourly meteorological and solar radiation data for 53 weather stations in and around Texas, including:–Dry-bulb temperature–Dew-point temperature–Relative humidity–Wind speed–Wind direction–Atmospheric pressure–Global horizontal radiation–Direct normal radiation–Diffuse horizontal radiation
TMY Algorithm
Typical Meteorological Data (TMY)•TMY files for 53 weather stations (Class I & II)•Composed of 12 typical meteorological months (January through December) that are concatenated to form a single year.•One TMY file contains a single representative year (8,760 data points).
Statistical analysis selects 12 “typical” months from 20-year data set to complete one full
year
Raw Data for this Project
Data Conversion▫ NSRDB data conversion process
– National Renewable Energy Laboratory (NREL) System Advisor Model (SAM) requires weather data in TMY2, TMY3 or EPW format
– URS converted NCDC-formatted NSRDB data to the TMY3 format for use as an input to SAM. The conversion process was automated using Bash shell scripts and Unix programming languages, including AWK and SED.
– Result was 21 TMY3-formatted meteorological data files for each of the 53 Class I/II weather stations (1,113 TMY3 files total)
Project Overview
National Renewable Energy Laboratory (NREL) System Advisor Model (SAM)
NREL SAM
▫ Available for free at NREL SAM website:– https://sam.nrel.gov/– URS used most recent version (2013.1.15)– Selected for many reasons over other options:• Transparency/replicability of study results• Flexibility in raw data sourcing• Ability to run automated scripts for fast data processing
Solar Technologies
▫ Fixed tilt crystalline silicon▫ Single-axis tracking (SAT)▫ Residential rooftop (fixed C-Si)▫ Concentrating Solar Power (CSP)
Fixed Tilt Crystalline Silicon (C-Si)
▫ Majority of PV arrays composed of C-Si cells▫ Lowest initial cost per watt▫ Polycrystalline efficiency: 13-16%▫ Monocrystalline efficiency: 14-20%▫ Ideally oriented due south with slope (tilt) of
modules equal to latitude
Single-Axis Tracker (SAT)▫ Increase the energy produced by a solar array by
tracking the sun from east to west diurnally▫ Tilt of SAT systems are usually kept flat, normal to the
zenith, and have a total east-west tracking range of 90°.
▫ SAT systems are designed to maximize land use without causing self-shading
Rooftop Residential▫ Utilize the same components of a fixed-tilt system,
but is constrained to the orientation of the building roof
▫ Typically range from 2kW to 16kW
Concentrating solar power (CSP)▫ Utilize concentrated solar radiation to generate
thermal energy, which is used to power a conventional electricity producing steam turbine generator
▫ Two primary types of plants: parabolic troughs and power towers
▫ URS elected to model a parabolic trough type CSP plant
Solar Radiation Levels across US
CSP Resource in Texas
Final Datasets
▫ Individual models configured in SAM for each technology type– Fixed tilt C-Si = 1MW– SAT = 1MW– Residential = 10kW– CSP = 50MW
▫ 20° selected for slope of fixed tilt system – most typical installation in Texas
Project Overview
Station-County Grouping
▫ US DOE used algorithms to define “zones of influence” around Class I/II weather stations at 10km2 blocks
Station-County Grouping
Station-County Grouping
Final Model Result Datasets
▫ Each of 1,113 TMY3 files fed into each model using automated script
▫ Output was 4,452 individual solar production model results containing 8,760 rows
▫ Post-production of data to generate total hourly AC output zeroing out any overnight consumption
▫ Results for each of four technologies available for any county in Texas based on associated weather station
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsLufkin Angelina Co (722446)
PVSAT PVFT RES CSP
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsAustin Mueller Muni AP (UT) (722540)
PVSAT PVFT RES CSP
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsBrownsville/So Padre Island Intl AP (722500)
PVSAT PVFT RES CSP
Model results normalized to 50 MW to match CSP system
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsDallas Ft. Worth Intl AP (722590)
PVSAT PVFT RES CSP
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsLubbock Intl AP (722670)
PVSAT PVFT RES CSP
20-Year Production Model Results
0
20,000
40,000
60,000
80,000
100,000
120,000
140,000
160,000
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
MW
h
20-Year Annual Electricity Production Model ResultsEl Paso Intl AP (722700)
PVSAT PVFT RES CSP
Project Overview
Data Quality & Statistical Analysis
▫ Final datasets reviewed for data quality and alignment with typical production profiles using URS internal technical review (ITR) process
0
100
200
300
400
500
600
700
800
900
1000
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46 49 52 55 58 61 64 67 70 73 76 79 82 85 88 91 94 97 100
103
106
109
112
115
118
121
124
127
130
133
136
139
142
145
148
151
154
157
160
163
166
Austin Mueller production model results – PVFT (blue), SAT (red) – 7/1/10 – 7/8/10
Statistical Variability Calculations
▫ Purpose: calculate the likelihood that a solar plant will generate a certain amount of electricity in any given year
▫ Exceedance probabilities (P50 & P90) can be calculated by fitting the dataset to a standard probability distribution and determining value from the cumulative distribution function (CDF).
▫ P50/P90 calculations prepared for six stations across TX using 20 years of production model results
Exceedance Probabilities
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
2,000 2,050 2,100 2,150 2,200 2,250 2,300 2,350 2,400MWh
Lubbock Intl AP (722670)
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
1,600 1,700 1,800 1,900 2,000 2,100MWh
Dallas Ft Worth Intl AP (722590)
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
2,100 2,200 2,300 2,400 2,500MWh
El Paso Intl AP (722700)
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
1,600 1,700 1,800 1,900 2,000 2,100MWh
Lufkin Angelina Co (722446)
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
1,600 1,700 1,800 1,900 2,000 2,100MWh
Austin Mueller Muni AP (UT) (722540)
0.0000.1000.2000.3000.4000.5000.6000.7000.8000.9001.000
1,600 1,700 1,800 1,900 2,000 2,100MWh
Brownsville/So Padre Intl AP (722500)
Weather Station Variance Analysis
▫ Graph below shows the % variance in total annual production model estimates between the Class I station shown and a nearby Class I or II station
▫ Many Class II stations relied upon inferior statistically derived cloud cover data prior to 1998 when satellite imagery data was introduced
-15.0%
-10.0%
-5.0%
0.0%
5.0%
10.0%
15.0%
1991 1992 1993 1994 1995 1996 1997 1998 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010
DFW Intl Airport Houston Bush Intl AP San Antonio Intl AP Austin Mueller AP (UT) Lubbock Intl AP
Angle of Incidence and SAT
▫ During winter months, SAT systems have “dip” in production during middle of day due to angle of incidence
SAT production model results - Odessa (blue), Nacogdoches (red) – 1/1/10 – 1/2/10
Angle of Incidence and SAT
Black & Veatch Solar Diagnostics Presentation
2011 Data
▫ Kevin contacted Michael Milligan at NREL to ask about availability of 2011 NCDC format NSRDB hourly solar data with the filled meteorological fields for the Class I & II weather stations in Texas
▫ No reliable 2011 meteorological data acquired in time for this project
