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I am writing a program to evaluate the hourly energy output from PV in various cities in the US. For simplicity, I have them in a dictionary (tmy3_cities) so that I can loop through them. To read the code, I followed the TMY to Power Tutorial off Github. Rather than showing the whole loop, I have only added the code that reads and shifts the time by 30-min.

Accordingly, the code taken from the tutorial works for all of the TMY3 files except for Houston, Atlanta, and Baltimore (HAB, for simplicity). All of the tmy3 files were downloaded from NREL and renamed for my own use. The error I get in reading these three files is related to the datetime, and it essentially comes down to a "ValueError: invalid literal for int() with base 10: '1' after some traceback.

Rather than looping into the same problem, I entered each file into the reader individually, and sure enough, only the HAB tmy3 files give errors.

Secondly, I downloaded the files again. This, obviously had no impact.

In a lazy attempt to bypass the issue, I copied and pasted the date and time columns from working tmy3 files (e.g., Miami) into the non-working ones (i.e., HAB) via excel.

I am not sure what else to do, as I am still fairly new to Python and coding in general.

#The dictionary below is not important to the problem below, but is 
provided only for some clarification.
tmy3_cities = {'miami': 'TMY3Miami.csv',
        'houston': 'TMY3Houston.csv',
        'phoenix': 'TMY3Phoenix.csv',
        'atlanta': 'TMY3Atlanta.csv',
        'los_angeles': 'TMY3LosAngeles.csv',
        'las_vegas': 'TMY3LasVegas.csv',
        'san_francisco': 'TMY3SanFrancisco.csv',
        'baltimore': 'TMY3Baltimore.csv',
        'albuquerque': 'TMY3Albuquerque.csv',
        'seattle': 'TMY3Seattle.csv',
        'chicago': 'TMY3Chicago.csv',
        'denver': 'TMY3Denver.csv',
        'minneapolis': 'TMY3Minneapolis.csv',
        'helena': 'TMY3Helena.csv',
        'duluth': 'TMY3Duluth.csv',
        'fairbanks': 'TMY3Fairbanks.csv'}

#The code below was taken from the tutorial.
pvlib_abspath = os.path.dirname(os.path.abspath(inspect.getfile(pvlib)))

#This is the only section of the code that was modified.
datapath = os.path.join(pvlib_abspath, 'data', 'TMY3Atlanta.csv')

tmy_data, meta = pvlib.tmy.readtmy3(datapath, coerce_year=2015)
tmy_data.index.name = 'Time'

# TMY data seems to be given as hourly data with time stamp at the end
# Shift the index 30 Minutes back for calculation of sun positions
tmy_data = tmy_data.shift(freq='-30Min')['2015']

print(tmy_data.head())

I would expect each tmy3 file that is read to produce its own tmy_data DataFrame. Please comment if you'd like to see the whole

Osvaldo
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  • Have you tried reading directly from the NREL website? I have no trouble reading Houston (Bush Intercontinental), Atlanta, and Baltimore files directly from the website. e.g. `dataatl, metadataatl = pvlib.iotools.read_tmy3('https://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/data/tmy3/722190TYA.CSV', coerce_year=2015)`. Maybe an issue between when you download and when you read. – Will Holmgren Apr 09 '19 at 22:45
  • Hello Will! Thanks for the quick response. Your suggestion fixed the issue for both Atlanta and Houston; however, I now get a new error for Baltimore: 'ValueError: day is out of range for month'. I am currently searching the website to see if anyone else has run into this error. – Osvaldo Apr 10 '19 at 20:40

0 Answers0