Accept albedo in weather input to ModelChain.run_model method (#1478)

* permit albedo to be a Series

* work on modelchain

* fix tests

* shh stickler, docstrings

* improve coverage

* improve coverage correctly

* finalize coverage, stickler

* whatsnew

* from review

* don't mutate inputs

* get_irradiance in tracking.py

* shh stickler

* shh stickler

* improvements from review

* update whatsnew

* Apply suggestions from code review

Co-authored-by: Kevin Anderson <kevin.anderson@nrel.gov>

* docstring improvements

* Apply suggestions from code review

Co-authored-by: Will Holmgren <william.holmgren@gmail.com>

* Update pvlib/tests/test_irradiance.py

Co-authored-by: Will Holmgren <william.holmgren@gmail.com>

* from review

* one more

* more use of fixture, add Array.get_irradiance test

* more decimal places

* spacing

* line length

* write albedo from system.arrays to ModelChainResult

Co-authored-by: Kevin Anderson <kevin.anderson@nrel.gov>
Co-authored-by: Will Holmgren <william.holmgren@gmail.com>

Author: 3 people

docs/sphinx/source/whatsnew/v0.9.2.rst

@@ -8,6 +8,10 @@ Deprecations
 
 Enhancements
 ~~~~~~~~~~~~
+* albedo can now be provided as a column in the `weather` DataFrame input to
+  :py:method:`pvlib.modelchain.ModelChain.run_model`. (:issue:`1387`, :pull:`1478`)
+* albedo is now available as an input to :py:meth:`pvlib.pvsystem.PVSystem.get_irradiance`
+  and :py:meth:`pvlib.pvsystem.Array.get_irradiance`. (:pull:`1478`)
 * :py:func:`pvlib.iotools.read_surfrad` now also accepts remote files
   with https links in addition to files on the SURFRAD FTP server
   (:pull:`1459`)
@@ -20,14 +24,15 @@ Enhancements
 * Add support for `PEP517 <https://peps.python.org/pep-0517/>`_ & `PEP518 <https://peps.python.org/pep-0518/>`_
   with setuptools build backend. (:pull:`1495`)
 
+
 Bug fixes
 ~~~~~~~~~
 * :py:func:`pvlib.irradiance.get_total_irradiance` and
   :py:func:`pvlib.solarposition.spa_python` now raise an error instead
-  of silently ignoring unknown parameters (:pull:`1437`)
+  of silently ignoring unknown parameters. (:pull:`1437`)
 * Fix a bug in :py:func:`pvlib.solarposition.sun_rise_set_transit_ephem`
   where passing localized timezones with large UTC offsets could return
-  rise/set/transit times for the wrong day in recent versions of ``ephem``
+  rise/set/transit times for the wrong day in recent versions of ``ephem``.
   (:issue:`1449`, :pull:`1448`)
 * :py:func:`pvlib.iotools.read_tmy3` is now able to accept midnight
   timestamps as either 24:00 (which is the standard) as well as 00:00.
@@ -68,6 +73,7 @@ Contributors
 * Naman Priyadarshi (:ghuser:`Naman-Priyadarshi`)
 * Chencheng Luo (:ghuser:`roger-lcc`)
 * Prajwal Borkar (:ghuser:`PrajwalBorkar`) 
+* Cliff Hansen (:ghuser:`cwhanse`)
 * Kevin Anderson (:ghuser:`kanderso-nrel`)
 * Cliff Hansen (:ghuser:`cwhanse`)
 * Jules Chéron (:ghuser:`jules-ch`)

pvlib/clearsky.py

@@ -960,8 +960,8 @@ def bird(zenith, airmass_relative, aod380, aod500, precipitable_water,
         Extraterrestrial radiation [W/m^2], defaults to 1364[W/m^2]
     asymmetry : numeric
         Asymmetry factor, defaults to 0.85
-    albedo : numeric
-        Albedo, defaults to 0.2
+    albedo : numeric, default 0.2
+        Ground surface albedo. [unitless]
 
     Returns
     -------

pvlib/irradiance.py

@@ -304,7 +304,7 @@ def beam_component(surface_tilt, surface_azimuth, solar_zenith, solar_azimuth,
 def get_total_irradiance(surface_tilt, surface_azimuth,
                          solar_zenith, solar_azimuth,
                          dni, ghi, dhi, dni_extra=None, airmass=None,
-                         albedo=.25, surface_type=None,
+                         albedo=0.25, surface_type=None,
                          model='isotropic',
                          model_perez='allsitescomposite1990'):
     r"""
@@ -344,7 +344,7 @@ def get_total_irradiance(surface_tilt, surface_azimuth,
     airmass : None or numeric, default None
         Relative airmass (not adjusted for pressure). [unitless]
     albedo : numeric, default 0.25
-        Surface albedo. [unitless]
+        Ground surface albedo. [unitless]
     surface_type : None or str, default None
         Surface type. See :py:func:`~pvlib.irradiance.get_ground_diffuse` for
         the list of accepted values.
@@ -1872,7 +1872,7 @@ def gti_dirint(poa_global, aoi, solar_zenith, solar_azimuth, times,
         applied.
 
     albedo : numeric, default 0.25
-        Surface albedo
+        Ground surface albedo. [unitless]
 
     model : String, default 'perez'
         Irradiance model.  See :py:func:`get_sky_diffuse` for allowed values.

pvlib/modelchain.py

@@ -268,7 +268,7 @@ class ModelChainResult:
     _per_array_fields = {'total_irrad', 'aoi', 'aoi_modifier',
                          'spectral_modifier', 'cell_temperature',
                          'effective_irradiance', 'dc', 'diode_params',
-                         'dc_ohmic_losses', 'weather'}
+                         'dc_ohmic_losses', 'weather', 'albedo'}
 
     # system-level information
     solar_position: Optional[pd.DataFrame] = field(default=None)
@@ -366,6 +366,10 @@ class ModelChainResult:
     """DatetimeIndex containing a copy of the index of the input weather data.
     """
 
+    albedo: Optional[PerArray[pd.Series]] = None
+    """Series (or tuple of Series, one for each array) containing albedo.
+    """
+
     def _result_type(self, value):
         """Coerce `value` to the correct type according to
         ``self._singleton_tuples``."""
@@ -1339,6 +1343,17 @@ def _prep_inputs_solar_pos(self, weather):
             **kwargs)
         return self
 
+    def _prep_inputs_albedo(self, weather):
+        """
+        Get albedo from weather
+        """
+        try:
+            self.results.albedo = _tuple_from_dfs(weather, 'albedo')
+        except KeyError:
+            self.results.albedo = tuple([
+                a.albedo for a in self.system.arrays])
+        return self
+
     def _prep_inputs_airmass(self):
         """
         Assign airmass
@@ -1471,11 +1486,17 @@ def prepare_inputs(self, weather):
 
         Parameters
         ----------
-        weather : DataFrame, or tuple or list of DataFrame
+        weather : DataFrame, or tuple or list of DataFrames
             Required column names include ``'dni'``, ``'ghi'``, ``'dhi'``.
-            Optional column names are ``'wind_speed'``, ``'temp_air'``; if not
+            Optional column names are ``'wind_speed'``, ``'temp_air'``,
+            ``'albedo'``.
+
+            If optional columns ``'wind_speed'``, ``'temp_air'`` are not
             provided, air temperature of 20 C and wind speed
-            of 0 m/s will be added to the DataFrame.
+            of 0 m/s will be added to the ``weather`` DataFrame.
+
+            If optional column ``'albedo'`` is provided, albedo values in the
+            ModelChain's PVSystem.arrays are ignored.
 
             If `weather` is a tuple or list, it must be of the same length and
             order as the Arrays of the ModelChain's PVSystem.
@@ -1494,7 +1515,7 @@ def prepare_inputs(self, weather):
         Notes
         -----
         Assigns attributes to ``results``: ``times``, ``weather``,
-        ``solar_position``, ``airmass``, ``total_irrad``, ``aoi``
+        ``solar_position``, ``airmass``, ``total_irrad``, ``aoi``, ``albedo``.
 
         See also
         --------
@@ -1507,6 +1528,7 @@ def prepare_inputs(self, weather):
 
         self._prep_inputs_solar_pos(weather)
         self._prep_inputs_airmass()
+        self._prep_inputs_albedo(weather)
 
         # PVSystem.get_irradiance and SingleAxisTracker.get_irradiance
         # and PVSystem.get_aoi and SingleAxisTracker.get_aoi
@@ -1531,6 +1553,7 @@ def prepare_inputs(self, weather):
             _tuple_from_dfs(self.results.weather, 'dni'),
             _tuple_from_dfs(self.results.weather, 'ghi'),
             _tuple_from_dfs(self.results.weather, 'dhi'),
+            albedo=self.results.albedo,
             airmass=self.results.airmass['airmass_relative'],
             model=self.transposition_model
         )
@@ -1724,16 +1747,32 @@ def run_model(self, weather):
         Parameters
         ----------
         weather : DataFrame, or tuple or list of DataFrame
-            Irradiance column names must include ``'dni'``, ``'ghi'``, and
-            ``'dhi'``. If optional columns ``'temp_air'`` and ``'wind_speed'``
+            Column names must include:
+
+            - ``'dni'``
+            - ``'ghi'``
+            - ``'dhi'``
+
+            Optional columns are:
+
+            - ``'temp_air'``
+            - ``'cell_temperature'``
+            - ``'module_temperature'``
+            - ``'wind_speed'``
+            - ``'albedo'``
+
+            If optional columns ``'temp_air'`` and ``'wind_speed'``
             are not provided, air temperature of 20 C and wind speed of 0 m/s
             are added to the DataFrame. If optional column
             ``'cell_temperature'`` is provided, these values are used instead
-            of `temperature_model`. If optional column `module_temperature`
-            is provided, `temperature_model` must be ``'sapm'``.
+            of `temperature_model`. If optional column ``'module_temperature'``
+            is provided, ``temperature_model`` must be ``'sapm'``.
 
-            If list or tuple, must be of the same length and order as the
-            Arrays of the ModelChain's PVSystem.
+            If optional column ``'albedo'`` is provided, ``'albedo'`` may not
+            be present on the ModelChain's PVSystem.Arrays.
+
+            If weather is a list or tuple, it must be of the same length and
+            order as the Arrays of the ModelChain's PVSystem.
 
         Returns
         -------