diff --git a/.github/workflows/pytest-remote-data.yml b/.github/workflows/pytest-remote-data.yml
index 66fda9cdea..9aa72b1514 100644
--- a/.github/workflows/pytest-remote-data.yml
+++ b/.github/workflows/pytest-remote-data.yml
@@ -96,7 +96,7 @@ jobs:
         shell: bash -l {0}  # necessary for conda env to be active
         env:
           # copy GitHub Secrets into environment variables for the tests to access
-          NREL_API_KEY: ${{ secrets.NRELAPIKEY }}
+          NLR_API_KEY: ${{ secrets.NRELAPIKEY }}
           SOLARANYWHERE_API_KEY: ${{ secrets.SOLARANYWHERE_API_KEY }}
           BSRN_FTP_USERNAME: ${{ secrets.BSRN_FTP_USERNAME }}
           BSRN_FTP_PASSWORD: ${{ secrets.BSRN_FTP_PASSWORD }}
diff --git a/.gitignore b/.gitignore
index c9d19f557d..0258b3975c 100644
--- a/.gitignore
+++ b/.gitignore
@@ -99,3 +99,8 @@ coverage.xml
 env
 results
 
+
+# Gas Town runtime
+.beads/
+.claude/
+.runtime/
diff --git a/docs/examples/bifacial/plot_irradiance_nonuniformity_loss.py b/docs/examples/bifacial/plot_irradiance_nonuniformity_loss.py
index cb0d4c4634..281f0954b5 100644
--- a/docs/examples/bifacial/plot_irradiance_nonuniformity_loss.py
+++ b/docs/examples/bifacial/plot_irradiance_nonuniformity_loss.py
@@ -47,7 +47,7 @@
 # described in Figure 1 (A), [1]_. We will cover this case for educational
 # purposes, although it can be achieved with the packages
 # `solarfactors <https://github.com/pvlib/solarfactors/>`_ and
-# `bifacial_radiance <https://github.com/NREL/bifacial_radiance>`_.
+# `bifacial_radiance <https://github.com/NatLabRockies/bifacial_radiance>`_.
 #
 # Here we set and plot the global irradiance level of each cell.
 
diff --git a/docs/examples/irradiance-decomposition/plot_diffuse_fraction.py b/docs/examples/irradiance-decomposition/plot_diffuse_fraction.py
index 7eb11a53f5..16b801b3c6 100644
--- a/docs/examples/irradiance-decomposition/plot_diffuse_fraction.py
+++ b/docs/examples/irradiance-decomposition/plot_diffuse_fraction.py
@@ -52,7 +52,7 @@
 # ----
 #
 # DISC :py:func:`~pvlib.irradiance.disc` is an empirical correlation developed
-# at SERI (now NREL) in 1987. The direct normal irradiance (DNI) is related to
+# at SERI (now NLR) in 1987. The direct normal irradiance (DNI) is related to
 # clearness index (kt) by two polynomials split at kt = 0.6, then combined with
 # an exponential relation with airmass.
 
@@ -216,5 +216,5 @@
 # correlations, which include additional variables such as airmass. These
 # methods seem to reduce DNI spikes over 1000 [W/m^2].
 #
-# .. _TMY3: https://www.nrel.gov/docs/fy08osti/43156.pdf
-# .. _NSRDB: https://www.nrel.gov/docs/fy12osti/54824.pdf
+# .. _TMY3: https://doi.org/10.2172/928611
+# .. _NSRDB: https://doi.org/10.2172/1054832
diff --git a/docs/examples/spectrum/average_photon_energy.py b/docs/examples/spectrum/average_photon_energy.py
index e4b8ef4cc7..57918da3b5 100644
--- a/docs/examples/spectrum/average_photon_energy.py
+++ b/docs/examples/spectrum/average_photon_energy.py
@@ -34,7 +34,7 @@
 from scipy.integrate import trapezoid
 from pvlib import spectrum, solarposition, irradiance, atmosphere
 
-lat, lon = 39.742, -105.18  # NREL SRRL location
+lat, lon = 39.742, -105.18  # SRRL location
 surface_tilt = 25
 surface_azimuth = 180  # south-facing system
 pressure = 81190  # at 1828 metres AMSL, roughly
@@ -194,5 +194,5 @@
 #        for the solar spectral influence on photovoltaic device performance."
 #        Energy 286 :doi:`10.1016/j.energy.2023.129461`
 # .. [4] Bird Simple Spectral Model: spectrl2_2.c
-#        https://www.nrel.gov/grid/solar-resource/spectral.html
-#        (Last accessed: 18/09/2024)
+#        https://www.nlr.gov/grid/solar-resource/spectral
+#        (Last accessed: 03/03/2026)
diff --git a/docs/sphinx/source/reference/iotools.rst b/docs/sphinx/source/reference/iotools.rst
index 1461534a4c..b2b306eaf1 100644
--- a/docs/sphinx/source/reference/iotools.rst
+++ b/docs/sphinx/source/reference/iotools.rst
@@ -179,7 +179,7 @@ A solar radiation network in the USA, run by NOAA.
 MIDC
 ^^^^
 
-A solar radiation network in the USA, run by NREL.
+A solar radiation network in the USA, run by NLR.
 
 .. autosummary::
    :toctree: generated/
diff --git a/docs/sphinx/source/reference/solarposition.rst b/docs/sphinx/source/reference/solarposition.rst
index dbe93d5392..f642ff411b 100644
--- a/docs/sphinx/source/reference/solarposition.rst
+++ b/docs/sphinx/source/reference/solarposition.rst
@@ -43,7 +43,7 @@ Functions for calculating sunrise, sunset and transit times.
    solarposition.sun_rise_set_transit_geometric
 
 
-The spa module contains the implementation of the built-in NREL SPA
+The spa module contains the implementation of the built-in NLR SPA
 algorithm.
 
 .. autosummary::
diff --git a/docs/sphinx/source/user_guide/extras/faq.rst b/docs/sphinx/source/user_guide/extras/faq.rst
index 29eeef7c2b..81b69731d9 100644
--- a/docs/sphinx/source/user_guide/extras/faq.rst
+++ b/docs/sphinx/source/user_guide/extras/faq.rst
@@ -126,7 +126,7 @@ The CEC table doesn't include my module or inverter, what should I do?
 ----------------------------------------------------------------------
 
 The CEC tables for module and inverter parameters included in pvlib are periodically
-copied from `SAM <https://github.com/NREL/SAM/tree/develop/deploy/libraries>`_,
+copied from `SAM <https://github.com/NatLabRockies/SAM/tree/develop/deploy/libraries>`_,
 so you can check the tables there for more up-to-date tables.
 
 For modules, if even the SAM files don't include the module you're looking for
diff --git a/docs/sphinx/source/user_guide/extras/nrel_nlr.rst b/docs/sphinx/source/user_guide/extras/nrel_nlr.rst
new file mode 100644
index 0000000000..6bb7a5cd8c
--- /dev/null
+++ b/docs/sphinx/source/user_guide/extras/nrel_nlr.rst
@@ -0,0 +1,30 @@
+.. _nrel_nlr:
+
+==============================
+NREL to NLR Rename (Dec 2025)
+==============================
+
+In December 2025, the U.S. Department of Energy renamed the
+**National Renewable Energy Laboratory (NREL)** to the
+**National Laboratory of the Rockies (NLR)**.
+
+
+Domain migration
+****************
+
+The lab's website moved from ``nrel.gov`` to ``nlr.gov``.  The ``nrel.gov``
+domain is expected to stop resolving on **May 29, 2026**.  The GitHub
+organization moved from ``github.com/NREL`` to ``github.com/NatLabRockies``.
+pvlib will update API and repository URLs as the migration progresses.
+
+
+When we use NREL vs NLR
+***********************
+
+- **NREL**: historical publications, citations, and algorithm references
+  (e.g. the NREL SPA) published under the original name.
+- **NLR**: the current organization, its software and data products,
+  and new ``nlr.gov`` URLs.
+
+Most existing pvlib code and docs say "NREL" because it appears in
+bibliographic citations.  These do not need to be updated.
diff --git a/docs/sphinx/source/user_guide/getting_started/installation.rst b/docs/sphinx/source/user_guide/getting_started/installation.rst
index 8212c5b251..955f5c9ac3 100644
--- a/docs/sphinx/source/user_guide/getting_started/installation.rst
+++ b/docs/sphinx/source/user_guide/getting_started/installation.rst
@@ -235,22 +235,22 @@ Alternatively, users may install all optional dependencies using
 
 .. _nrelspa:
 
-NREL SPA algorithm
+NLR SPA algorithm
 ------------------
 
 pvlib-python is distributed with several validated, high-precision, and
 high-performance solar position calculators. We strongly recommend using
 the built-in solar position calculators.
 
-pvlib-python also includes unsupported wrappers for the official NREL
-SPA algorithm. NREL's license does not allow redistribution of the
+pvlib-python also includes unsupported wrappers for the official NLR
+SPA algorithm. NLR's license does not allow redistribution of the
 source code, so you must jump through some hoops to use it with pvlib.
 You will need a C compiler to use this code.
 
-To install the NREL SPA algorithm for use with pvlib:
+To install the NLR SPA algorithm for use with pvlib:
 
 #. Download the pvlib repository (as described in :ref:`obtainsource`)
-#. Download the `SPA files from NREL <http://www.nrel.gov/midc/spa/>`_
+#. Download the `SPA files from NLR <http://www.nlr.gov/midc/spa/>`_
 #. Copy the SPA files into ``pvlib-python/pvlib/spa_c_files``
 #. From the ``pvlib-python`` directory, run ``pip uninstall pvlib``
    followed by ``pip install .``
diff --git a/docs/sphinx/source/user_guide/index.rst b/docs/sphinx/source/user_guide/index.rst
index af2a4cbb92..973ac0b025 100644
--- a/docs/sphinx/source/user_guide/index.rst
+++ b/docs/sphinx/source/user_guide/index.rst
@@ -34,4 +34,5 @@ This user guide is an overview and explains some of the key features of pvlib.
    :caption: Extras
 
    extras/nomenclature
+   extras/nrel_nlr
    extras/faq
diff --git a/docs/sphinx/source/whatsnew/v0.15.1.rst b/docs/sphinx/source/whatsnew/v0.15.1.rst
index 83b13d01f0..959edbaa19 100644
--- a/docs/sphinx/source/whatsnew/v0.15.1.rst
+++ b/docs/sphinx/source/whatsnew/v0.15.1.rst
@@ -56,6 +56,11 @@ Requirements
 
 Maintenance
 ~~~~~~~~~~~
+* Update all NREL references to NLR (National Laboratory of the Rockies)
+  following the laboratory rename and domain migration from ``nrel.gov``
+  to ``nlr.gov``. Rename ``NREL_API_KEY`` environment variable to
+  ``NLR_API_KEY``. See :ref:`nrel_nlr` for details.
+  (:issue:`2701`, :pull:`2705`)
 
 
 Contributors
diff --git a/docs/tutorials/tmy_to_power.ipynb b/docs/tutorials/tmy_to_power.ipynb
index ae8fa43eb0..47fa9b4648 100644
--- a/docs/tutorials/tmy_to_power.ipynb
+++ b/docs/tutorials/tmy_to_power.ipynb
@@ -70,11 +70,7 @@
   {
    "cell_type": "markdown",
    "metadata": {},
-   "source": [
-    "pvlib comes with a couple of TMY files, and we'll use one of them for simplicity. You could also load a file from disk, or specify a url. See this NREL website for a list of TMY files:\n",
-    "\n",
-    "http://rredc.nrel.gov/solar/old_data/nsrdb/1991-2005/tmy3/by_state_and_city.html"
-   ]
+   "source": "pvlib comes with a couple of TMY files, and we'll use one of them for simplicity. You could also load a file from disk, or specify a url. See this NLR website for a list of TMY files:\n\nhttps://nsrdb.nlr.gov/data-sets/archives"
   },
   {
    "cell_type": "code",
@@ -1515,13 +1511,7 @@
   {
    "cell_type": "markdown",
    "metadata": {},
-   "source": [
-    "Next, we will assume that the SAPM model is representative of the real world performance so that we can use scipy's optimization routine to derive simulated PVUSA coefficients. You will need to install scipy to run these functions.\n",
-    "\n",
-    "Here's one PVUSA reference:\n",
-    "\n",
-    "http://www.nrel.gov/docs/fy09osti/45376.pdf\n"
-   ]
+   "source": "Next, we will assume that the SAPM model is representative of the real world performance so that we can use scipy's optimization routine to derive simulated PVUSA coefficients. You will need to install scipy to run these functions.\n\nHere's one PVUSA reference:\n\nhttps://www.osti.gov/biblio/951223\n"
   },
   {
    "cell_type": "code",
diff --git a/pvlib/atmosphere.py b/pvlib/atmosphere.py
index dcd34da6bc..f17a8e5866 100644
--- a/pvlib/atmosphere.py
+++ b/pvlib/atmosphere.py
@@ -448,7 +448,7 @@ def bird_hulstrom80_aod_bb(aod380, aod500):
     References
     ----------
     .. [1] Bird and Hulstrom, "Direct Insolation Models" (1980)
-       `SERI/TR-335-344 <http://www.nrel.gov/docs/legosti/old/344.pdf>`_
+       `SERI/TR-335-344 <http://www.nlr.gov/docs/legosti/old/344.pdf>`_
 
     .. [2] R. E. Bird and R. L. Hulstrom, "Review, Evaluation, and Improvement
        of Direct Irradiance Models", Journal of Solar Energy Engineering
diff --git a/pvlib/bifacial/infinite_sheds.py b/pvlib/bifacial/infinite_sheds.py
index be9f426fdd..f99c536315 100644
--- a/pvlib/bifacial/infinite_sheds.py
+++ b/pvlib/bifacial/infinite_sheds.py
@@ -166,7 +166,7 @@ def _shaded_fraction(solar_zenith, solar_azimuth, surface_tilt,
        :doi:`10.1109/PVSC40753.2019.8980572`.
     .. [2] Kevin Anderson and Mark Mikofski, "Slope-Aware Backtracking for
        Single-Axis Trackers", Technical Report NREL/TP-5K00-76626, July 2020.
-       https://www.nrel.gov/docs/fy20osti/76626.pdf
+       :doi:`10.2172/1660126`
     """
     tan_phi = utils._solar_projection_tangent(
         solar_zenith, solar_azimuth, surface_azimuth)
diff --git a/pvlib/bifacial/loss_models.py b/pvlib/bifacial/loss_models.py
index 3582e8a6c9..4c6f0febf3 100644
--- a/pvlib/bifacial/loss_models.py
+++ b/pvlib/bifacial/loss_models.py
@@ -135,7 +135,7 @@ def power_mismatch_deline(
     --------
     `solarfactors <https://github.com/pvlib/solarfactors/>`_
         Calculate the irradiance at different points of the module.
-    `bifacial_radiance <https://github.com/NREL/bifacial_radiance>`_
+    `bifacial_radiance <https://github.com/NatLabRockies/bifacial_radiance>`_
         Calculate the irradiance at different points of the module.
 
     References
diff --git a/pvlib/clearsky.py b/pvlib/clearsky.py
index 8cc867e020..66b732e328 100644
--- a/pvlib/clearsky.py
+++ b/pvlib/clearsky.py
@@ -942,7 +942,7 @@ def bird(zenith, airmass_relative, aod380, aod500, precipitable_water,
     """
     Bird Simple Clear Sky Broadband Solar Radiation Model
 
-    Based on NREL Excel implementation by Daryl R. Myers [1, 2].
+    Based on NLR Excel implementation by Daryl R. Myers [1, 2].
 
     Bird and Hulstrom define the zenith as the "angle between a line to
     the sun and the local zenith". There is no distinction in the paper
@@ -953,7 +953,7 @@ def bird(zenith, airmass_relative, aod380, aod500, precipitable_water,
     was to compare existing clear sky models with "rigorous radiative
     transfer models" (RTM) it is possible that apparent zenith was
     obtained as output from the RTM. However, the implementation presented
-    in PVLIB is tested against the NREL Excel implementation by Daryl
+    in PVLIB is tested against the NLR Excel implementation by Daryl
     Myers which uses an analytical expression for solar zenith instead
     of apparent zenith.
 
@@ -1001,13 +1001,13 @@ def bird(zenith, airmass_relative, aod380, aod500, precipitable_water,
     .. [2] Daryl R. Myers, "Solar Radiation: Practical Modeling for Renewable
        Energy Applications", pp. 46-51 CRC Press (2013)
 
-    .. [3] `NREL Bird Clear Sky Model <http://rredc.nrel.gov/solar/models/
-       clearsky/>`_
+    .. [3] `Bird Clear Sky Model <http://www.nlr.gov/grid/solar-resource/
+       clearsky.html>`_
 
-    .. [4] `SERI/TR-642-761 <https://www.nrel.gov/docs/legosti/old/761.pdf>`_
+    .. [4] SERI/TR-642-761 :doi:`10.2172/6510849`
 
-    .. [5] `Error Reports <http://rredc.nrel.gov/solar/models/clearsky/
-       error_reports.html>`_
+    .. [5] `Error Reports <http://www.nlr.gov/grid/solar-resource/
+       clearsky-error-reports.html>`_
     """
     etr = dni_extra  # extraradiation
     ze_rad = np.deg2rad(zenith)  # zenith in radians
diff --git a/pvlib/inverter.py b/pvlib/inverter.py
index a6a80863eb..622fb9b958 100644
--- a/pvlib/inverter.py
+++ b/pvlib/inverter.py
@@ -117,7 +117,7 @@ def sandia(v_dc, p_dc, inverter):
        for Grid-Connected Photovoltaic Inverters", Sandia National
        Laboratories, Albuquerque, N.M., USA, SAND2007-5036, Sept. 2007.
        :doi:`10.2172/920449`
-    .. [2] System Advisor Model web page. https://sam.nrel.gov.
+    .. [2] System Advisor Model web page. https://sam.nlr.gov.
 
     See also
     --------
@@ -335,7 +335,7 @@ def adr(v_dc, p_dc, inverter, vtol=0.10):
 
 def pvwatts(pdc, pdc0, eta_inv_nom=0.96, eta_inv_ref=0.9637):
     r"""
-    NREL's PVWatts inverter model.
+    NLR's PVWatts inverter model.
 
     The PVWatts inverter model [1]_ calculates inverter efficiency :math:`\eta`
     as a function of input DC power :math:`P_{dc}`
@@ -414,7 +414,7 @@ def pvwatts(pdc, pdc0, eta_inv_nom=0.96, eta_inv_ref=0.9637):
 
 def pvwatts_multi(pdc, pdc0, eta_inv_nom=0.96, eta_inv_ref=0.9637):
     r"""
-    Extend NREL's PVWatts inverter model for multiple MPP inputs.
+    Extend NLR's PVWatts inverter model for multiple MPP inputs.
 
     DC input power is summed over MPP inputs to obtain the DC power
     input to the PVWatts inverter model. See :py:func:`pvlib.inverter.pvwatts`
diff --git a/pvlib/iotools/midc.py b/pvlib/iotools/midc.py
index c0dfd370eb..e2fe435125 100644
--- a/pvlib/iotools/midc.py
+++ b/pvlib/iotools/midc.py
@@ -1,4 +1,4 @@
-"""Functions to read NREL MIDC data.
+"""Functions to read NLR MIDC data.
 """
 import io
 
@@ -15,7 +15,7 @@
 #
 # In particular, these mappings coincide with the raw ddata files.
 # All site's field list can be found at:
-#     https://midcdmz.nrel.gov/apps/daily.pl?site=<SITE ID>&live=1
+#     https://midcdmz.nlr.gov/apps/daily.pl?site=<SITE ID>&live=1
 # Where id is the key found in this dictionary
 MIDC_VARIABLE_MAP = {
     'BMS': {
@@ -158,7 +158,7 @@ def _format_index_raw(data):
 
 
 def read_midc(filename, variable_map={}, raw_data=False, **kwargs):
-    """Read in National Renewable Energy Laboratory Measurement and
+    """Read in National Laboratory of the Rockies Measurement and
     Instrumentation Data Center weather data.  The MIDC is described in [1]_.
 
     Parameters
@@ -196,12 +196,12 @@ def read_midc(filename, variable_map={}, raw_data=False, **kwargs):
     :ref:`nomenclature`.
 
     Be sure to check the units for the variables you will use on the
-    `MIDC site <https://midcdmz.nrel.gov/>`_.
+    `MIDC site <https://midcdmz.nlr.gov/>`_.
 
     References
     ----------
-    .. [1] NREL: Measurement and Instrumentation Data Center
-        `https://midcdmz.nrel.gov/ <https://midcdmz.nrel.gov/>`_
+    .. [1] NLR: Measurement and Instrumentation Data Center
+        `https://midcdmz.nlr.gov/ <https://midcdmz.nlr.gov/>`_
     """
     data = pd.read_csv(filename, **kwargs)
     if raw_data:
@@ -248,13 +248,13 @@ def read_midc_raw_data_from_nrel(site, start, end, variable_map={},
     -----
     Requests spanning an instrumentation change will yield an error. See the
     MIDC raw data api page
-    `here <https://midcdmz.nrel.gov/apps/data_api_doc.pl?_idtextlist>`_
+    `here <https://midcdmz.nlr.gov/apps/data_api_doc.pl?_idtextlist>`_
     for more details and considerations.
     """
     args = {'site': site,
             'begin': pd.to_datetime(start).strftime('%Y%m%d'),
             'end': pd.to_datetime(end).strftime('%Y%m%d')}
-    url = 'https://midcdmz.nrel.gov/apps/data_api.pl'
+    url = 'https://midcdmz.nlr.gov/apps/data_api.pl'
     # NOTE: just use requests.get(url, params=args) to build querystring
     # number of header columns and data columns do not always match,
     # so first parse the header to determine the number of data columns
diff --git a/pvlib/iotools/psm4.py b/pvlib/iotools/psm4.py
index ecab84fd21..9eb760f382 100644
--- a/pvlib/iotools/psm4.py
+++ b/pvlib/iotools/psm4.py
@@ -1,9 +1,9 @@
 """
 Functions for reading and retrieving data from NSRDB PSM4. See:
-https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-aggregated-v4-0-0-download/
-https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-tmy-v4-0-0-download/
-https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-conus-v4-0-0-download/
-https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-full-disc-v4-0-0-download/
+https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-aggregated-v4-0-0-download/
+https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-tmy-v4-0-0-download/
+https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-conus-v4-0-0-download/
+https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-full-disc-v4-0-0-download/
 """
 
 import io
@@ -13,7 +13,7 @@
 from json import JSONDecodeError
 from pvlib import tools
 
-NSRDB_API_BASE = "https://developer.nrel.gov/api/nsrdb/v2/solar/"
+NSRDB_API_BASE = "https://developer.nlr.gov/api/nsrdb/v2/solar/"
 PSM4_AGG_ENDPOINT = "nsrdb-GOES-aggregated-v4-0-0-download.csv"
 PSM4_TMY_ENDPOINT = "nsrdb-GOES-tmy-v4-0-0-download.csv"
 PSM4_CON_ENDPOINT = "nsrdb-GOES-conus-v4-0-0-download.csv"
@@ -92,9 +92,9 @@ def get_nsrdb_psm4_aggregated(latitude, longitude, api_key, email,
     longitude : float or int
         in decimal degrees, between -180 and 180, east is positive
     api_key : str
-        NREL Developer Network API key
+        NLR Developer Network API key
     email : str
-        NREL API uses this to automatically communicate messages back
+        NLR API uses this to automatically communicate messages back
         to the user only if necessary
     year : int or str
         PSM4 API parameter specifing year (e.g. ``2023``) to download. The
@@ -130,9 +130,9 @@ def get_nsrdb_psm4_aggregated(latitude, longitude, api_key, email,
     Returns
     -------
     data : pandas.DataFrame
-        timeseries data from NREL PSM4
+        timeseries data from NLR PSM4
     metadata : dict
-        metadata from NREL PSM4 about the record, see
+        metadata from NLR PSM4 about the record, see
         :func:`pvlib.iotools.read_nsrdb_psm4` for fields
 
     Raises
@@ -145,8 +145,8 @@ def get_nsrdb_psm4_aggregated(latitude, longitude, api_key, email,
 
     Notes
     -----
-    The required NREL developer key, `api_key`, is available for free by
-    registering at the `NREL Developer Network <https://developer.nrel.gov/>`_.
+    The required NLR developer key, `api_key`, is available for free by
+    registering at the `NLR Developer Network <https://developer.nlr.gov/>`_.
 
     .. warning:: The "DEMO_KEY" `api_key` is severely rate limited and may
         result in rejected requests.
@@ -161,10 +161,10 @@ def get_nsrdb_psm4_aggregated(latitude, longitude, api_key, email,
 
     References
     ----------
-    .. [1] `NREL National Solar Radiation Database (NSRDB)
-       <https://nsrdb.nrel.gov/>`_
+    .. [1] `NLR National Solar Radiation Database (NSRDB)
+       <https://developer.nlr.gov/docs/solar/nsrdb/>`_
     .. [2] `NSRDB GOES Aggregated V4.0.0
-       <https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-aggregated-v4-0-0-download/>`_
+       <https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-aggregated-v4-0-0-download/>`_
     """
     # The well know text (WKT) representation of geometry notation is strict.
     # A POINT object is a string with longitude first, then the latitude, with
@@ -191,7 +191,7 @@ def get_nsrdb_psm4_aggregated(latitude, longitude, api_key, email,
         'utc': str(utc).lower(),
         'interval': time_step
     }
-    # request CSV download from NREL PSM4
+    # request CSV download from NLR PSM4
     if url is None:
         url = PSM4_AGG_URL
 
@@ -228,9 +228,9 @@ def get_nsrdb_psm4_tmy(latitude, longitude, api_key, email, year='tmy',
     longitude : float or int
         in decimal degrees, between -180 and 180, east is positive
     api_key : str
-        NREL Developer Network API key
+        NLR Developer Network API key
     email : str
-        NREL API uses this to automatically communicate messages back
+        NLR API uses this to automatically communicate messages back
         to the user only if necessary
     year : str, default 'tmy'
         PSM4 API parameter specifing TMY variant to download (e.g. ``'tmy'``
@@ -267,9 +267,9 @@ def get_nsrdb_psm4_tmy(latitude, longitude, api_key, email, year='tmy',
     Returns
     -------
     data : pandas.DataFrame
-        timeseries data from NREL PSM4
+        timeseries data from NLR PSM4
     metadata : dict
-        metadata from NREL PSM4 about the record, see
+        metadata from NLR PSM4 about the record, see
         :func:`pvlib.iotools.read_nsrdb_psm4` for fields
 
     Raises
@@ -282,8 +282,8 @@ def get_nsrdb_psm4_tmy(latitude, longitude, api_key, email, year='tmy',
 
     Notes
     -----
-    The required NREL developer key, `api_key`, is available for free by
-    registering at the `NREL Developer Network <https://developer.nrel.gov/>`_.
+    The required NLR developer key, `api_key`, is available for free by
+    registering at the `NLR Developer Network <https://developer.nlr.gov/>`_.
 
     .. warning:: The "DEMO_KEY" `api_key` is severely rate limited and may
         result in rejected requests.
@@ -299,10 +299,10 @@ def get_nsrdb_psm4_tmy(latitude, longitude, api_key, email, year='tmy',
 
     References
     ----------
-    .. [1] `NREL National Solar Radiation Database (NSRDB)
-       <https://nsrdb.nrel.gov/>`_
+    .. [1] `NLR National Solar Radiation Database (NSRDB)
+       <https://developer.nlr.gov/docs/solar/nsrdb/>`_
     .. [2] `NSRDB GOES Tmy V4.0.0
-       <https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-tmy-v4-0-0-download/>`_
+       <https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-tmy-v4-0-0-download/>`_
     """
     # The well know text (WKT) representation of geometry notation is strict.
     # A POINT object is a string with longitude first, then the latitude, with
@@ -329,7 +329,7 @@ def get_nsrdb_psm4_tmy(latitude, longitude, api_key, email, year='tmy',
         'utc': str(utc).lower(),
         'interval': time_step
     }
-    # request CSV download from NREL PSM4
+    # request CSV download from NLR PSM4
     if url is None:
         url = PSM4_TMY_URL
 
@@ -366,9 +366,9 @@ def get_nsrdb_psm4_conus(latitude, longitude, api_key, email, year,
     longitude : float or int
         in decimal degrees, between -180 and 180, east is positive
     api_key : str
-        NREL Developer Network API key
+        NLR Developer Network API key
     email : str
-        NREL API uses this to automatically communicate messages back
+        NLR API uses this to automatically communicate messages back
         to the user only if necessary
     year : int or str
         PSM4 API parameter specifing year (e.g. ``2023``) to download. The
@@ -403,9 +403,9 @@ def get_nsrdb_psm4_conus(latitude, longitude, api_key, email, year,
     Returns
     -------
     data : pandas.DataFrame
-        timeseries data from NREL PSM4
+        timeseries data from NLR PSM4
     metadata : dict
-        metadata from NREL PSM4 about the record, see
+        metadata from NLR PSM4 about the record, see
         :func:`pvlib.iotools.read_nsrdb_psm4` for fields
 
     Raises
@@ -418,8 +418,8 @@ def get_nsrdb_psm4_conus(latitude, longitude, api_key, email, year,
 
     Notes
     -----
-    The required NREL developer key, `api_key`, is available for free by
-    registering at the `NREL Developer Network <https://developer.nrel.gov/>`_.
+    The required NLR developer key, `api_key`, is available for free by
+    registering at the `NLR Developer Network <https://developer.nlr.gov/>`_.
 
     .. warning:: The "DEMO_KEY" `api_key` is severely rate limited and may
         result in rejected requests.
@@ -435,10 +435,10 @@ def get_nsrdb_psm4_conus(latitude, longitude, api_key, email, year,
 
     References
     ----------
-    .. [1] `NREL National Solar Radiation Database (NSRDB)
-       <https://nsrdb.nrel.gov/>`_
+    .. [1] `NLR National Solar Radiation Database (NSRDB)
+       <https://developer.nlr.gov/docs/solar/nsrdb/>`_
     .. [2] `NSRDB GOES Conus V4.0.0
-       <https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-conus-v4-0-0-download/>`_
+       <https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-conus-v4-0-0-download/>`_
     """
     # The well know text (WKT) representation of geometry notation is strict.
     # A POINT object is a string with longitude first, then the latitude, with
@@ -465,7 +465,7 @@ def get_nsrdb_psm4_conus(latitude, longitude, api_key, email, year,
         'utc': str(utc).lower(),
         'interval': time_step
     }
-    # request CSV download from NREL PSM4
+    # request CSV download from NLR PSM4
     if url is None:
         url = PSM4_CON_URL
 
@@ -504,9 +504,9 @@ def get_nsrdb_psm4_full_disc(latitude, longitude, api_key, email,
     longitude : float or int
         in decimal degrees, between -180 and 180, east is positive
     api_key : str
-        NREL Developer Network API key
+        NLR Developer Network API key
     email : str
-        NREL API uses this to automatically communicate messages back
+        NLR API uses this to automatically communicate messages back
         to the user only if necessary
     year : int or str
         PSM4 API parameter specifing year (e.g. ``2023``) to download. The
@@ -542,9 +542,9 @@ def get_nsrdb_psm4_full_disc(latitude, longitude, api_key, email,
     Returns
     -------
     data : pandas.DataFrame
-        timeseries data from NREL PSM4
+        timeseries data from NLR PSM4
     metadata : dict
-        metadata from NREL PSM4 about the record, see
+        metadata from NLR PSM4 about the record, see
         :func:`pvlib.iotools.read_nsrdb_psm4` for fields
 
     Raises
@@ -557,8 +557,8 @@ def get_nsrdb_psm4_full_disc(latitude, longitude, api_key, email,
 
     Notes
     -----
-    The required NREL developer key, `api_key`, is available for free by
-    registering at the `NREL Developer Network <https://developer.nrel.gov/>`_.
+    The required NLR developer key, `api_key`, is available for free by
+    registering at the `NLR Developer Network <https://developer.nlr.gov/>`_.
 
     .. warning:: The "DEMO_KEY" `api_key` is severely rate limited and may
         result in rejected requests.
@@ -574,10 +574,10 @@ def get_nsrdb_psm4_full_disc(latitude, longitude, api_key, email,
 
     References
     ----------
-    .. [1] `NREL National Solar Radiation Database (NSRDB)
-       <https://nsrdb.nrel.gov/>`_
+    .. [1] `NLR National Solar Radiation Database (NSRDB)
+       <https://developer.nlr.gov/docs/solar/nsrdb/>`_
     .. [2] `NSRDB GOES Full Disc V4.0.0
-       <https://developer.nrel.gov/docs/solar/nsrdb/nsrdb-GOES-full-disc-v4-0-0-download/>`_
+       <https://developer.nlr.gov/docs/solar/nsrdb/nsrdb-GOES-full-disc-v4-0-0-download/>`_
     """
     # The well know text (WKT) representation of geometry notation is strict.
     # A POINT object is a string with longitude first, then the latitude, with
@@ -604,7 +604,7 @@ def get_nsrdb_psm4_full_disc(latitude, longitude, api_key, email,
         'utc': str(utc).lower(),
         'interval': time_step
     }
-    # request CSV download from NREL PSM4
+    # request CSV download from NLR PSM4
     if url is None:
         url = PSM4_FUL_URL
 
@@ -640,16 +640,16 @@ def read_nsrdb_psm4(filename, map_variables=True):
     Returns
     -------
     data : pandas.DataFrame
-        timeseries data from NREL PSM4
+        timeseries data from NLR PSM4
     metadata : dict
-        metadata from NREL PSM4 about the record, see notes for fields
+        metadata from NLR PSM4 about the record, see notes for fields
 
     Notes
     -----
     The return is a tuple with two items. The first item is a dataframe with
     the PSM4 timeseries data.
 
-    The second item is a dictionary with metadata from NREL PSM4 about the
+    The second item is a dictionary with metadata from NLR PSM4 about the
     record containing the following fields:
 
     * Source
@@ -717,8 +717,8 @@ def read_nsrdb_psm4(filename, map_variables=True):
 
     References
     ----------
-    .. [1] `NREL National Solar Radiation Database (NSRDB)
-       <https://nsrdb.nrel.gov/>`_
+    .. [1] `NLR National Solar Radiation Database (NSRDB)
+       <https://developer.nlr.gov/docs/solar/nsrdb/>`_
     .. [2] `Standard Time Series Data File Format
        <https://web.archive.org/web/20170207203107/https://sam.nrel.gov/sites/default/files/content/documents/pdf/wfcsv.pdf>`_
     """
diff --git a/pvlib/iotools/tmy.py b/pvlib/iotools/tmy.py
index 28d20ffc2d..0527e2633c 100644
--- a/pvlib/iotools/tmy.py
+++ b/pvlib/iotools/tmy.py
@@ -161,7 +161,7 @@ def read_tmy3(filename, coerce_year=None, map_variables=True, encoding=None):
 
     .. admonition:: Midnight representation
 
-       The function is able to handle midnight represented as 24:00 (NREL TMY3
+       The function is able to handle midnight represented as 24:00 (NLR TMY3
        format, see [1]_) and as 00:00 (SolarAnywhere TMY3 format, see [3]_).
 
     .. warning:: TMY3 irradiance data corresponds to the *previous* hour, so
diff --git a/pvlib/irradiance.py b/pvlib/irradiance.py
index c67c1ca251..26e6f4d3b1 100644
--- a/pvlib/irradiance.py
+++ b/pvlib/irradiance.py
@@ -89,7 +89,7 @@ def get_extra_radiation(datetime_or_doy, solar_constant=1366.1,
        Engineers, 2005. :doi:`10.1061/9780784408056`
 
     .. [6] I. Reda, A. Andreas, "Solar position algorithm for solar
-       radiation applications" NREL Golden, USA. NREL/TP-560-34302,
+       radiation applications" NREL Golden, CO, USA. NREL/TP-560-34302,
        Revised 2008. :doi:`10.2172/15003974`
     """
 
@@ -1730,7 +1730,7 @@ def clearness_index_zenith_independent(clearness_index, airmass,
     max_clearness_index : numeric, default 2.0
         Maximum value of the clearness index. The default, 2.0, allows
         for over-irradiance events typically seen in sub-hourly data.
-        NREL's SRRL Fortran code used 0.82 for hourly data.
+        NLR's SRRL Fortran code used 0.82 for hourly data.
 
     Returns
     -------
@@ -1774,7 +1774,7 @@ def disc(ghi, solar_zenith, datetime_or_doy, pressure=101325,
 
     The original report describing the DISC model [1]_ uses the
     relative airmass rather than the absolute (pressure-corrected)
-    airmass. However, the NREL implementation of the DISC model [2]_
+    airmass. However, the NLR implementation of the DISC model [2]_
     uses absolute airmass. PVLib Matlab also uses the absolute airmass.
     pvlib python defaults to absolute airmass, but the relative airmass
     can be used by supplying `pressure=None`.
@@ -1828,7 +1828,7 @@ def disc(ghi, solar_zenith, datetime_or_doy, pressure=101325,
        Institute, 1987.
 
     .. [2] Maxwell, E. "DISC Model", Excel Worksheet.
-       https://www.nrel.gov/grid/solar-resource/disc.html
+       https://www.nlr.gov/grid/solar-resource/disc.html
 
     See Also
     --------
diff --git a/pvlib/ivtools/utils.py b/pvlib/ivtools/utils.py
index cde50655dc..91c862f88a 100644
--- a/pvlib/ivtools/utils.py
+++ b/pvlib/ivtools/utils.py
@@ -470,7 +470,7 @@ def astm_e1036(v, i, imax_limits=(0.75, 1.15), vmax_limits=(0.75, 1.15),
        ASTM E1036-15(2019), :doi:`10.1520/E1036-15R19`
     '''
 
-    # Adapted from https://github.com/NREL/iv_params
+    # Adapted from https://github.com/NatLabRockies/iv_params
     # Copyright (c) 2022, Alliance for Sustainable Energy, LLC
     # All rights reserved.
 
diff --git a/pvlib/pvsystem.py b/pvlib/pvsystem.py
index fe85359b99..5512f362ad 100644
--- a/pvlib/pvsystem.py
+++ b/pvlib/pvsystem.py
@@ -1561,7 +1561,7 @@ def calcparams_desoto(effective_irradiance, temp_cell,
         The energy bandgap at reference temperature in units of eV.
         1.121 eV for crystalline silicon. EgRef must be >0.  For parameters
         from the SAM CEC module database, EgRef=1.121 is implicit for all
-        cell types in the parameter estimation algorithm used by NREL.
+        cell types in the parameter estimation algorithm used by NLR.
 
     dEgdT : float
         The temperature dependence of the energy bandgap at reference
@@ -1569,7 +1569,7 @@ def calcparams_desoto(effective_irradiance, temp_cell,
         (e.g. -0.0002677 as in [1]_) or a DataFrame (this may be useful if
         dEgdT is a modeled as a function of temperature). For parameters from
         the SAM CEC module database, dEgdT=-0.0002677 is implicit for all cell
-        types in the parameter estimation algorithm used by NREL.
+        types in the parameter estimation algorithm used by NLR.
 
     irrad_ref : float, default 1000
         Reference irradiance in W/m^2.
@@ -1604,7 +1604,7 @@ def calcparams_desoto(effective_irradiance, temp_cell,
        photovoltaic array performance", Solar Energy, vol 80, pp. 78-88,
        2006.
 
-    .. [2] System Advisor Model web page. https://sam.nrel.gov.
+    .. [2] System Advisor Model web page. https://sam.nlr.gov.
 
     .. [3] A. Dobos, "An Improved Coefficient Calculator for the California
        Energy Commission 6 Parameter Photovoltaic Module Model", Journal of
@@ -1779,7 +1779,7 @@ def calcparams_cec(effective_irradiance, temp_cell,
         The energy bandgap at reference temperature in units of eV.
         1.121 eV for crystalline silicon. EgRef must be >0.  For parameters
         from the SAM CEC module database, EgRef=1.121 is implicit for all
-        cell types in the parameter estimation algorithm used by NREL.
+        cell types in the parameter estimation algorithm used by NLR.
 
     dEgdT : float
         The temperature dependence of the energy bandgap at reference
@@ -1787,7 +1787,7 @@ def calcparams_cec(effective_irradiance, temp_cell,
         (e.g. -0.0002677 as in [3]) or a DataFrame (this may be useful if
         dEgdT is a modeled as a function of temperature). For parameters from
         the SAM CEC module database, dEgdT=-0.0002677 is implicit for all cell
-        types in the parameter estimation algorithm used by NREL.
+        types in the parameter estimation algorithm used by NLR.
 
     irrad_ref : float, default 1000
         Reference irradiance in W/m^2.
@@ -1822,7 +1822,7 @@ def calcparams_cec(effective_irradiance, temp_cell,
        Energy Commission 6 Parameter Photovoltaic Module Model", Journal of
        Solar Energy Engineering, vol 134, 2012.
 
-    .. [2] System Advisor Model web page. https://sam.nrel.gov.
+    .. [2] System Advisor Model web page. https://sam.nlr.gov.
 
     .. [3] W. De Soto et al., "Improvement and validation of a model for
        photovoltaic array performance", Solar Energy, vol 80, pp. 78-88,
@@ -2084,7 +2084,7 @@ def retrieve_sam(name=None, path=None):
     Notes
     -----
     Files available at
-        https://github.com/NREL/SAM/tree/develop/deploy/libraries
+        https://github.com/NatLabRockies/SAM/tree/develop/deploy/libraries
 
     Examples
     --------
@@ -2889,7 +2889,7 @@ def scale_voltage_current_power(data, voltage=1, current=1):
 def pvwatts_dc(effective_irradiance, temp_cell, pdc0, gamma_pdc, temp_ref=25.,
                k=None, cap_adjustment=False):
     r"""
-    Implement NREL's PVWatts (Version 5) DC power model.
+    Implement NLR's PVWatts (Version 5) DC power model.
 
     Parameters
     ----------
@@ -2963,7 +2963,7 @@ def pvwatts_dc(effective_irradiance, temp_cell, pdc0, gamma_pdc, temp_ref=25.,
        Module Performance," In Proc. 33rd IEEE Photovoltaic Specialists
        Conference (PVSC), San Diego, CA, USA, 2008, pp. 1-6,
        :doi:`10.1109/PVSC.2008.4922586`.
-       Pre-print: https://docs.nrel.gov/docs/fy08osti/42511.pdf
+       Pre-print: :doi:`10.1109/PVSC.2008.4922586`
     """  # noqa: E501
 
     pdc = (effective_irradiance * 0.001 * pdc0 *
@@ -3004,7 +3004,7 @@ def pvwatts_losses(soiling=2, shading=3, snow=0, mismatch=2, wiring=2,
                    connections=0.5, lid=1.5, nameplate_rating=1, age=0,
                    availability=3):
     r"""
-    Implements NREL's PVWatts system loss model.
+    Implements NLR's PVWatts system loss model.
     The PVWatts loss model [1]_ is:
 
     .. math::
diff --git a/pvlib/shading.py b/pvlib/shading.py
index 42aef892f7..8fb50e5d3d 100644
--- a/pvlib/shading.py
+++ b/pvlib/shading.py
@@ -88,7 +88,7 @@ def masking_angle(surface_tilt, gcr, slant_height):
        :doi:`10.1016/0379-6787(84)90017-6`
     .. [2] Gilman, P. et al., (2018). "SAM Photovoltaic Model Technical
        Reference Update", NREL Technical Report NREL/TP-6A20-67399.
-       Available at https://www.nrel.gov/docs/fy18osti/67399.pdf
+       :doi:`10.2172/1429291`
     """
     # The original equation (8 in [1]) requires pitch and collector width,
     # but it's easy to non-dimensionalize it to make it a function of GCR
@@ -229,7 +229,7 @@ def sky_diffuse_passias(masking_angle):
        :doi:`10.1016/0379-6787(84)90017-6`
     .. [2] Gilman, P. et al., (2018). "SAM Photovoltaic Model Technical
        Reference Update", NREL Technical Report NREL/TP-6A20-67399.
-       Available at https://www.nrel.gov/docs/fy18osti/67399.pdf
+       :doi:`10.2172/1429291`
     """
     return 1 - cosd(masking_angle/2)**2
 
diff --git a/pvlib/snow.py b/pvlib/snow.py
index f2c8fca148..3723a85dfe 100644
--- a/pvlib/snow.py
+++ b/pvlib/snow.py
@@ -159,7 +159,7 @@ def coverage_nrel(snowfall, poa_irradiance, temp_air, surface_tilt,
         # All slides off if snow on the ground is less than threshold_depth.
         # Described in [2] to avoid non-sliding snow for low-tilt systems.
         # Default threshold_depth of 1cm is from [2[ and SAM's implementation.
-        # https://github.com/NREL/ssc/issues/1265
+        # https://github.com/NatLabRockies/ssc/issues/1265
         slide_amt[snow_depth < threshold_depth] = 1.
 
     # build time series of cumulative slide amounts
@@ -211,7 +211,7 @@ def dc_loss_nrel(snow_coverage, num_strings):
     ----------
     .. [1] Gilman, P. et al., (2018). "SAM Photovoltaic Model Technical
        Reference Update", NREL Technical Report NREL/TP-6A20-67399.
-       Available at https://www.nrel.gov/docs/fy18osti/67399.pdf
+       Available at https://www.nlr.gov/docs/fy18osti/67399.pdf
     '''
     return np.ceil(snow_coverage * num_strings) / num_strings
 
@@ -320,7 +320,7 @@ def loss_townsend(snow_total, snow_events, surface_tilt, relative_humidity,
         Uses of the Townsend Snow Model. In "Photovoltaic Reliability
         Workshop (PVRW) 2023 Proceedings: Posters.", ed. Silverman,
         T. J. Dec. 2023. NREL/CP-5900-87918.
-        Available at: https://www.nrel.gov/docs/fy25osti/90585.pdf
+        :doi:`10.2172/1429291`
     .. [3] Townsend, T. (2013). Predicting PV Energy Loss Caused by Snow.
         Solar Power International, Chicago IL.
         :doi:`10.13140/RG.2.2.14299.68647`
diff --git a/pvlib/solarposition.py b/pvlib/solarposition.py
index 2b8a43e9d0..15eb9eeeab 100644
--- a/pvlib/solarposition.py
+++ b/pvlib/solarposition.py
@@ -56,10 +56,10 @@ def get_solarposition(time, latitude, longitude,
         if ``altitude`` is not supplied.
 
     method : string, default 'nrel_numpy'
-        'nrel_numpy' uses an implementation of the NREL SPA algorithm
+        'nrel_numpy' uses an implementation of the NLR SPA algorithm
         described in [1] (default, recommended): :py:func:`spa_python`
 
-        'nrel_numba' uses an implementation of the NREL SPA algorithm
+        'nrel_numba' uses an implementation of the NLR SPA algorithm
         described in [1], but also compiles the code first:
         :py:func:`spa_python`
 
@@ -67,7 +67,7 @@ def get_solarposition(time, latitude, longitude,
 
         'ephemeris' uses the pvlib ephemeris code: :py:func:`ephemeris`
 
-        'nrel_c' uses the NREL SPA C code [3]: :py:func:`spa_c`
+        'nrel_c' uses the NLR SPA C code [3]: :py:func:`spa_c`
 
     temperature : float, default 12
         Degrees C.
@@ -85,7 +85,7 @@ def get_solarposition(time, latitude, longitude,
        solar radiation applications. Solar Energy, vol. 81, no. 6, p. 838,
        2007.
 
-    .. [3] NREL SPA code: https://midcdmz.nrel.gov/spa/
+    .. [3] NLR SPA code: https://midcdmz.nlr.gov/spa/
     """
 
     if altitude is None and pressure is None:
@@ -129,7 +129,7 @@ def spa_c(time, latitude, longitude, pressure=101325., altitude=0.,
           temperature=12., delta_t=67.0,
           raw_spa_output=False):
     r"""
-    Calculate the solar position using the C implementation of the NREL
+    Calculate the solar position using the C implementation of the NLR
     SPA code.
 
     The source files for this code are located in './spa_c_files/', along with
@@ -173,7 +173,7 @@ def spa_c(time, latitude, longitude, pressure=101325., altitude=0.,
 
     References
     ----------
-    .. [1] NREL SPA reference: https://midcdmz.nrel.gov/spa/
+    .. [1] NLR SPA reference: https://midcdmz.nlr.gov/spa/
 
     Note: The ``timezone`` field in the SPA C files is replaced with
     ``time_zone`` to avoid a nameclash with the function ``__timezone`` that is
@@ -283,9 +283,9 @@ def spa_python(time, latitude, longitude,
                atmos_refract=None, how='numpy', numthreads=4):
     """
     Calculate the solar position using a python implementation of the
-    NREL SPA algorithm.
+    NLR SPA algorithm.
 
-    The details of the NREL SPA algorithm are described in [1]_, [2]_.
+    The details of the NLR SPA algorithm are described in [1]_, [2]_.
 
     If numba is installed, the functions can be compiled to
     machine code and the function can be multithreaded.
@@ -394,9 +394,9 @@ def sun_rise_set_transit_spa(times, latitude, longitude, how='numpy',
                              delta_t=67.0, numthreads=4):
     """
     Calculate the sunrise, sunset, and sun transit times using the
-    NREL SPA algorithm.
+    NLR SPA algorithm.
 
-    The details of the NREL SPA algorithm are described in [1]_.
+    The details of the NLR SPA algorithm are described in [1]_.
 
     If numba is installed, the functions can be compiled to
     machine code and the function can be multithreaded.
@@ -432,8 +432,8 @@ def sun_rise_set_transit_spa(times, latitude, longitude, how='numpy',
     References
     ----------
     .. [1] Reda, I., Andreas, A., 2003. Solar position algorithm for solar
-       radiation applications. Technical report: NREL/TP-560- 34302. Golden,
-       USA, http://www.nrel.gov.
+       radiation applications. Technical report: NREL/TP-560-34302. Golden,
+       USA, http://www.nlr.gov.
     """
     # Added by Tony Lorenzo (@alorenzo175), University of Arizona, 2015
 
@@ -956,9 +956,9 @@ def pyephem_earthsun_distance(time):
 def nrel_earthsun_distance(time, how='numpy', delta_t=67.0, numthreads=4):
     """
     Calculates the distance from the earth to the sun using the
-    NREL SPA algorithm.
+    NLR SPA algorithm.
 
-    The details of the NREL SPA algorithm are described in [1]_.
+    The details of the NLR SPA algorithm are described in [1]_.
 
     Parameters
     ----------
@@ -987,8 +987,8 @@ def nrel_earthsun_distance(time, how='numpy', delta_t=67.0, numthreads=4):
     References
     ----------
     .. [1] Reda, I., Andreas, A., 2003. Solar position algorithm for solar
-       radiation applications. Technical report: NREL/TP-560- 34302. Golden,
-       USA, http://www.nrel.gov.
+       radiation applications. Technical report: NREL/TP-560-34302. Golden,
+       USA, http://www.nlr.gov.
     """
 
     if not isinstance(time, pd.DatetimeIndex):
diff --git a/pvlib/spa.py b/pvlib/spa.py
index 6297e88c35..3384bfe5ab 100644
--- a/pvlib/spa.py
+++ b/pvlib/spa.py
@@ -1,5 +1,5 @@
 """
-Calculate the solar position using the NREL SPA algorithm either using
+Calculate the solar position using the NLR SPA algorithm either using
 numpy arrays or compiling the code to machine language with numba.
 """
 
@@ -402,7 +402,7 @@ def nocompile(*args, **kwargs):
 @jcompile('float64(int64, int64, int64, int64, int64, int64, int64)',
           nopython=True)
 def julian_day_dt(year, month, day, hour, minute, second, microsecond):
-    """This is the original way to calculate the julian day from the NREL paper.
+    """This is the original way to calculate the julian day from the NLR paper.
     However, it is much faster to convert to unix/epoch time and then convert
     to julian day. Note that the date must be UTC."""
     if month <= 2:
@@ -1031,7 +1031,7 @@ def solar_position(unixtime, lat, lon, elev, pressure, temp, delta_t,
 
     """
     Calculate the solar position using the
-    NREL SPA algorithm described in [1].
+    NLR SPA algorithm described in [1].
 
     If numba is installed, the functions can be compiled
     and the code runs quickly. If not, the functions
@@ -1214,7 +1214,7 @@ def transit_sunrise_sunset(dates, lat, lon, delta_t, numthreads):
 def earthsun_distance(unixtime, delta_t, numthreads):
     """
     Calculates the distance from the earth to the sun using the
-    NREL SPA algorithm described in [1].
+    NLR SPA algorithm described in [1].
 
     Parameters
     ----------
@@ -1235,8 +1235,8 @@ def earthsun_distance(unixtime, delta_t, numthreads):
     References
     ----------
     [1] Reda, I., Andreas, A., 2003. Solar position algorithm for solar
-    radiation applications. Technical report: NREL/TP-560- 34302. Golden,
-    USA, http://www.nrel.gov.
+    radiation applications. Technical report: NREL/TP-560-34302. Golden,
+    USA, http://www.nlr.gov.
     """
 
     R = solar_position(unixtime, 0, 0, 0, 0, 0, delta_t,
diff --git a/pvlib/spa_c_files/README.md b/pvlib/spa_c_files/README.md
index aaef8bd571..69a9c28d4d 100644
--- a/pvlib/spa_c_files/README.md
+++ b/pvlib/spa_c_files/README.md
@@ -1,18 +1,18 @@
 README
 ------
 
-NREL provides a C implementation of the solar position algorithm described in
-[Reda, I.; Andreas, A. (2003). Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302](http://www.nrel.gov/docs/fy08osti/34302.pdf).
+NLR provides a C implementation of the solar position algorithm described in
+Reda, I.; Andreas, A. (2003). Solar Position Algorithm for Solar Radiation Applications. 55 pp.; NREL Report No. TP-560-34302. :doi:`10.2172/15003974`
 
 This folder contains the files required to make SPA C code accessible
-to the `pvlib-python` package. We use the Cython package to wrap the NREL SPA 
+to the `pvlib-python` package. We use the Cython package to wrap the NLR SPA
 implementation. 
 
 ** Due to licensing issues, the SPA C files can _not_ be distributed with
 `pvlib-python`. You must download the SPA C files from the
-[NREL website](https://midcdmz.nrel.gov/spa/). **
+[NLR website](https://midcdmz.nlr.gov/spa/). **
 
-Download the `spa.c` and `spa.h` files from NREL,  and copy them into the
+Download the `spa.c` and `spa.h` files from NLR,  and copy them into the
 `pvlib/spa_c_files` directory. When the extension is built, the ``timezone``
 field in the SPA C files is replaced with `time_zone` to avoid a nameclash
 with the function `__timezone` that is redefined by Python>=3.5. This issue
@@ -20,7 +20,7 @@ is [Python bug 24643](https://bugs.python.org/issue24643).
 
 There are a total of 5 files needed to compile the C code, described below:
 
-* `spa.c`: original C code from NREL 
+* `spa.c`: original C code from NLR
 * `spa.h`: header file for spa.c
 * `cspa_py.pxd`: a cython header file which essentially tells cython which
   parts of the main header file to pay attention to
diff --git a/pvlib/spectrum/irradiance.py b/pvlib/spectrum/irradiance.py
index fc3440cd19..4c8e70b693 100644
--- a/pvlib/spectrum/irradiance.py
+++ b/pvlib/spectrum/irradiance.py
@@ -47,8 +47,8 @@ def get_reference_spectra(wavelengths=None, standard="ASTM G173-03"):
     For global spectra, it is about 1000.37 W/m².
 
     The values of the ASTM G173-03 provided with pvlib-python are copied from
-    an Excel file distributed by NREL, which is found here [2]_:
-    https://www.nrel.gov/grid/solar-resource/assets/data/astmg173.xls
+    an Excel file distributed by NLR, which is found here [2]_:
+    https://www.nlr.gov/grid/solar-resource/assets/data/astmg173.xls
 
     Examples
     --------
@@ -78,8 +78,8 @@ def get_reference_spectra(wavelengths=None, standard="ASTM G173-03"):
     ----------
     .. [1] ASTM "G173-03 Standard Tables for Reference Solar Spectral
        Irradiances: Direct Normal and Hemispherical on 37° Tilted Surface."
-    .. [2] “Reference Air Mass 1.5 Spectra,” www.nrel.gov.
-       https://www.nrel.gov/grid/solar-resource/spectra-am1.5.html
+    .. [2] “Reference Air Mass 1.5 Spectra.” NLR.
+       https://www.nlr.gov/grid/solar-resource/spectra-am1.5.html
     """  # Contributed by Echedey Luis, inspired by Anton Driesse (get_am15g)
     SPECTRA_FILES = {
         "ASTM G173-03": "ASTMG173.csv",
diff --git a/pvlib/spectrum/mismatch.py b/pvlib/spectrum/mismatch.py
index b4385e255a..830c0be171 100644
--- a/pvlib/spectrum/mismatch.py
+++ b/pvlib/spectrum/mismatch.py
@@ -231,7 +231,7 @@ def spectral_factor_firstsolar(precipitable_water, airmass_absolute,
        Water." IEEE Photovoltaic Specialists Conference, Portland, 2016
     .. [3] Marion, William F., et al. User's Manual for Data for Validating
        Models for PV Module Performance. National Renewable Energy
-       Laboratory, 2014. http://www.nrel.gov/docs/fy14osti/61610.pdf
+       Laboratory, 2014. :doi:`10.2172/1130632`
     .. [4] Schweiger, M. and Hermann, W, Influence of Spectral Effects
        on Energy Yield of Different PV Modules: Comparison of Pwat and
        MMF Approach, TUV Rheinland Energy GmbH report 21237296.003,
diff --git a/pvlib/spectrum/spectrl2.py b/pvlib/spectrum/spectrl2.py
index 38739efff3..966c9d649a 100644
--- a/pvlib/spectrum/spectrl2.py
+++ b/pvlib/spectrum/spectrl2.py
@@ -203,7 +203,7 @@ def spectrl2(apparent_zenith, aoi, surface_tilt, ground_albedo,
         Surface pressure. [Pa]
     relative_airmass : numeric
         Relative airmass. The airmass model used in [1]_ is the `'kasten1966'`
-        model, while a later implementation by NREL uses the
+        model, while a later implementation by NLR uses the
         `'kastenyoung1989'` model. [unitless]
     precipitable_water : numeric
         Atmospheric water vapor content. [cm]
@@ -245,7 +245,7 @@ def spectrl2(apparent_zenith, aoi, surface_tilt, ground_albedo,
 
     Notes
     -----
-    NREL's C implementation ``spectrl2_2.c`` [2]_ of the model differs in
+    NLR's C implementation ``spectrl2_2.c`` [2]_ of the model differs in
     several ways from the original report [1]_.  The report itself also has
     a few differences between the in-text equations and the code appendix.
     The list of known differences is shown below.  Note that this
@@ -273,7 +273,7 @@ def spectrl2(apparent_zenith, aoi, surface_tilt, ground_albedo,
        earth's surface for cloudless atmospheres", NREL Technical Report
        TR-215-2436 :doi:`10.2172/5986936`.
     .. [2] Bird Simple Spectral Model: spectrl2_2.c.
-       https://www.nrel.gov/grid/solar-resource/spectral.html
+       https://www.nlr.gov/grid/solar-resource/spectral.html
     """
     # values need to be np arrays for broadcasting, so unwrap Series if needed:
     is_pandas = isinstance(apparent_zenith, pd.Series)
diff --git a/pvlib/tracking.py b/pvlib/tracking.py
index ae50a5bc3f..737d077a7b 100644
--- a/pvlib/tracking.py
+++ b/pvlib/tracking.py
@@ -114,7 +114,7 @@ def singleaxis(apparent_zenith, solar_azimuth,
     ----------
     .. [1] Anderson, K., and Mikofski, M., "Slope-Aware Backtracking for
        Single-Axis Trackers", Technical Report NREL/TP-5K00-76626, July 2020.
-       https://www.nrel.gov/docs/fy20osti/76626.pdf
+       :doi:`10.2172/1660126`
     .. [2] Lorenzo, E., Narvarte, L., and Muñoz, J. (2011). Tracking and
        back-tracking 19(6), 747–753. :doi:`10.1002/pip.1085`
     """
@@ -299,7 +299,7 @@ def calc_axis_tilt(slope_azimuth, slope_tilt, axis_azimuth):
     ----------
     .. [1] Kevin Anderson and Mark Mikofski, "Slope-Aware Backtracking for
        Single-Axis Trackers", Technical Report NREL/TP-5K00-76626, July 2020.
-       https://www.nrel.gov/docs/fy20osti/76626.pdf
+       :doi:`10.2172/1660126`
     """
     delta_gamma = axis_azimuth - slope_azimuth
     # equations 18-19
@@ -408,7 +408,7 @@ def calc_cross_axis_tilt(
     ----------
     .. [1] Kevin Anderson and Mark Mikofski, "Slope-Aware Backtracking for
        Single-Axis Trackers", Technical Report NREL/TP-5K00-76626, July 2020.
-       https://www.nrel.gov/docs/fy20osti/76626.pdf
+       :doi:`10.2172/1660126`
     """
     # delta-gamma, difference between axis and slope azimuths
     delta_gamma = axis_azimuth - slope_azimuth
diff --git a/tests/conftest.py b/tests/conftest.py
index dc14a34254..8a1c1180d8 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -86,20 +86,22 @@ def assert_frame_equal(left, right, **kwargs):
 
 
 @pytest.fixture(scope="module")
-def nrel_api_key():
-    """Supplies pvlib-python's NREL Developer Network API key.
-
-    pvlib's CI utilizes a secret variable set to NREL_API_KEY
-    to mitigate failures associated with using the default key of
-    "DEMO_KEY". A user is capable of using their own key this way if
-    desired however the default key should suffice for testing purposes.
+def nlr_api_key():
+    """Supplies pvlib-python's NLR Developer Network API key.
+
+    pvlib's CI utilizes a secret variable set to NLR_API_KEY
+    (formerly NREL_API_KEY) to mitigate failures associated with
+    using the default key of "DEMO_KEY". A user is capable of using
+    their own key this way if desired however the default key should
+    suffice for testing purposes.
     """
     try:
-        demo_key = os.environ["NREL_API_KEY"]
+        demo_key = os.environ["NLR_API_KEY"]
     except KeyError:
         warnings.warn(
-            "WARNING: NREL API KEY environment variable not set! "
-            "Using DEMO_KEY instead. Unexpected failures may occur."
+            "WARNING: NLR_API_KEY (formerly NREL_API_KEY) environment "
+            "variable not set! Using DEMO_KEY instead. "
+            "Unexpected failures may occur."
         )
         demo_key = 'DEMO_KEY'
     return demo_key
diff --git a/tests/iotools/test_midc.py b/tests/iotools/test_midc.py
index 9a327d1394..b1a9594744 100644
--- a/tests/iotools/test_midc.py
+++ b/tests/iotools/test_midc.py
@@ -23,7 +23,7 @@ def test_mapping():
     TESTS_DATA_DIR / 'midc_raw_short_header_20191115.txt')
 
 # TODO: not used, remove?
-# midc_network_testfile = ('https://midcdmz.nrel.gov/apps/data_api.pl'
+# midc_network_testfile = ('https://midcdmz.nlr.gov/apps/data_api.pl'
 #                          '?site=UAT&begin=20181018&end=20181019')
 
 
diff --git a/tests/iotools/test_psm4.py b/tests/iotools/test_psm4.py
index 6447aed33b..3d06c27a3d 100644
--- a/tests/iotools/test_psm4.py
+++ b/tests/iotools/test_psm4.py
@@ -4,7 +4,7 @@
 
 from pvlib.iotools import psm4
 from ..conftest import (
-    TESTS_DATA_DIR, RERUNS, RERUNS_DELAY, assert_index_equal, nrel_api_key
+    TESTS_DATA_DIR, RERUNS, RERUNS_DELAY, assert_index_equal, nlr_api_key
 )
 import numpy as np
 import pandas as pd
@@ -54,10 +54,10 @@ def assert_psm4_equal(data, metadata, expected):
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_tmy(nrel_api_key):
+def test_get_nsrdb_psm4_tmy(nlr_api_key):
     """test get_nsrdb_psm4_tmy with a TMY"""
     data, metadata = psm4.get_nsrdb_psm4_tmy(LATITUDE, LONGITUDE,
-                                             nrel_api_key, PVLIB_EMAIL,
+                                             nlr_api_key, PVLIB_EMAIL,
                                              year='tmy-2023',
                                              leap_day=False,
                                              map_variables=False)
@@ -67,10 +67,10 @@ def test_get_nsrdb_psm4_tmy(nrel_api_key):
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_full_disc(nrel_api_key):
+def test_get_nsrdb_psm4_full_disc(nlr_api_key):
     """test get_nsrdb_psm4_full_disc with a single year"""
     data, metadata = psm4.get_nsrdb_psm4_full_disc(LATITUDE, LONGITUDE,
-                                                   nrel_api_key, PVLIB_EMAIL,
+                                                   nlr_api_key, PVLIB_EMAIL,
                                                    year='2023',
                                                    leap_day=False,
                                                    map_variables=False)
@@ -80,10 +80,10 @@ def test_get_nsrdb_psm4_full_disc(nrel_api_key):
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_conus_singleyear(nrel_api_key):
+def test_get_nsrdb_psm4_conus_singleyear(nlr_api_key):
     """test get_nsrdb_psm4_conus with a single year"""
     data, metadata = psm4.get_nsrdb_psm4_aggregated(LATITUDE, LONGITUDE,
-                                                    nrel_api_key,
+                                                    nlr_api_key,
                                                     PVLIB_EMAIL,
                                                     year='2023',
                                                     leap_day=False,
@@ -95,10 +95,10 @@ def test_get_nsrdb_psm4_conus_singleyear(nrel_api_key):
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_conus_5min(nrel_api_key):
+def test_get_nsrdb_psm4_conus_5min(nlr_api_key):
     """test get_nsrdb_psm4_conus for 5-minute data"""
     data, metadata = psm4.get_nsrdb_psm4_conus(LATITUDE, LONGITUDE,
-                                               nrel_api_key, PVLIB_EMAIL,
+                                               nlr_api_key, PVLIB_EMAIL,
                                                year='2023', time_step=5,
                                                leap_day=False,
                                                map_variables=False)
@@ -110,10 +110,10 @@ def test_get_nsrdb_psm4_conus_5min(nrel_api_key):
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_aggregated_check_leap_day(nrel_api_key):
+def test_get_nsrdb_psm4_aggregated_check_leap_day(nlr_api_key):
     """test get_nsrdb_psm4_aggregated for leap day"""
     data_2012, _ = psm4.get_nsrdb_psm4_aggregated(LATITUDE, LONGITUDE,
-                                                  nrel_api_key, PVLIB_EMAIL,
+                                                  nlr_api_key, PVLIB_EMAIL,
                                                   year="2012", time_step=60,
                                                   leap_day=True,
                                                   map_variables=False)
@@ -122,9 +122,9 @@ def test_get_nsrdb_psm4_aggregated_check_leap_day(nrel_api_key):
 
 @pytest.mark.parametrize('latitude, longitude, api_key, year, time_step',
                          [(LATITUDE, LONGITUDE, 'BAD', '2023', 60),
-                          (51, -5, nrel_api_key, '2023', 60),
-                          (LATITUDE, LONGITUDE, nrel_api_key, 'bad', 60),
-                          (LATITUDE, LONGITUDE, nrel_api_key, '2023', 15),
+                          (51, -5, nlr_api_key, '2023', 60),
+                          (LATITUDE, LONGITUDE, nlr_api_key, 'bad', 60),
+                          (LATITUDE, LONGITUDE, nlr_api_key, '2023', 15),
                           ])
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
@@ -187,11 +187,11 @@ def test_read_nsrdb_psm4_map_variables():
 
 @pytest.mark.remote_data
 @pytest.mark.flaky(reruns=RERUNS, reruns_delay=RERUNS_DELAY)
-def test_get_nsrdb_psm4_aggregated_parameter_mapping(nrel_api_key):
+def test_get_nsrdb_psm4_aggregated_parameter_mapping(nlr_api_key):
     """Test that pvlib names can be passed in as parameters and get correctly
     reverse mapped to psm4 names"""
     data, meta = psm4.get_nsrdb_psm4_aggregated(
-        LATITUDE, LONGITUDE, nrel_api_key, PVLIB_EMAIL, year='2019',
+        LATITUDE, LONGITUDE, nlr_api_key, PVLIB_EMAIL, year='2019',
         time_step=60, parameters=['ghi', 'wind_speed'], leap_day=False,
         map_variables=True)
     # Check that columns are in the correct order (GH1647)
diff --git a/tests/iotools/test_tmy.py b/tests/iotools/test_tmy.py
index d50609ec47..23d824382f 100644
--- a/tests/iotools/test_tmy.py
+++ b/tests/iotools/test_tmy.py
@@ -107,7 +107,7 @@ def solaranywhere_index():
 
 def test_solaranywhere_tmy3(solaranywhere_index):
     # The SolarAnywhere TMY3 format specifies midnight as 00:00 whereas the
-    # NREL TMY3 format utilizes 24:00. The SolarAnywhere file is therefore
+    # NLR TMY3 format utilizes 24:00. The SolarAnywhere file is therefore
     # included to test files with  00:00 timestamps are parsed correctly
     data, meta = tmy.read_tmy3(TMY3_SOLARANYWHERE, encoding='iso-8859-1',
                                map_variables=False)
diff --git a/tests/spectrum/test_spectrl2.py b/tests/spectrum/test_spectrl2.py
index 38df01830f..c29429c7ea 100644
--- a/tests/spectrum/test_spectrl2.py
+++ b/tests/spectrum/test_spectrl2.py
@@ -6,7 +6,7 @@
 
 
 def test_spectrl2(spectrl2_data):
-    # compare against output from solar_utils wrapper around NREL spectrl2_2.c
+    # compare against output from solar_utils wrapper around NLR spectrl2_2.c
     kwargs, expected = spectrl2_data
     actual = spectrum.spectrl2(**kwargs)
     assert_allclose(expected['wavelength'].values, actual['wavelength'])
diff --git a/tests/test_shading.py b/tests/test_shading.py
index f83f2db47b..e856a57241 100644
--- a/tests/test_shading.py
+++ b/tests/test_shading.py
@@ -170,7 +170,7 @@ def test_projected_solar_zenith_angle_numeric(
 ):
     psza_func = shading.projected_solar_zenith_angle
     axis_tilt, axis_azimuth, timedata = true_tracking_angle_and_inputs_NREL
-    # test against data provided by NREL
+    # test against data provided by NLR
     psz = psza_func(
         timedata["Apparent Zenith"],
         timedata["Solar Azimuth"],
diff --git a/tests/test_solarposition.py b/tests/test_solarposition.py
index 68158ee7d6..a6cf6b4819 100644
--- a/tests/test_solarposition.py
+++ b/tests/test_solarposition.py
@@ -38,7 +38,7 @@ def expected_solpos_multi():
 
 @pytest.fixture()
 def expected_rise_set_spa():
-    # for Golden, CO, from NREL SPA website
+    # for Golden, CO, from NLR SPA website
     times = pd.DatetimeIndex([datetime.datetime(2015, 1, 2),
                               datetime.datetime(2015, 8, 2),
                               ]).tz_localize('MST')
@@ -86,8 +86,8 @@ def expected_rise_set_ephem():
                         index=times)
 
 
-# the physical tests are run at the same time as the NREL SPA test.
-# pyephem reproduces the NREL result to 2 decimal places.
+# the physical tests are run at the same time as the NLR SPA test.
+# pyephem reproduces the NLR result to 2 decimal places.
 # this doesn't mean that one code is better than the other.
 
 @requires_spa_c
@@ -142,7 +142,7 @@ def test_spa_python_numpy_physical_dst(expected_solpos, golden):
 
 @pytest.mark.parametrize('delta_t', [65.0, None, np.array([65, 65])])
 def test_sun_rise_set_transit_spa(expected_rise_set_spa, golden, delta_t):
-    # solution from NREL SPA web calculator
+    # solution from NLR SPA web calculator
     south = Location(-35.0, 0.0, tz='UTC')
     times = pd.to_datetime(["1996-07-05", "2004-12-04"], utc=True)
     sunrise = pd.to_datetime(["1996-07-05 07:08:15", "2004-12-04 04:38:57"],
@@ -168,7 +168,7 @@ def test_sun_rise_set_transit_spa(expected_rise_set_spa, golden, delta_t):
                        check_dtype=False  # ignore us/ns dtypes
                        )
 
-    # test for Golden, CO compare to NREL SPA
+    # test for Golden, CO compare to NLR SPA
     result = solarposition.sun_rise_set_transit_spa(
         expected_rise_set_spa.index, golden.latitude, golden.longitude,
         delta_t=delta_t)
@@ -672,7 +672,7 @@ def test_analytical_azimuth():
 def test_hour_angle():
     """
     Test conversion from hours to hour angles in degrees given the following
-    inputs from NREL SPA calculator at Golden, CO
+    inputs from NLR SPA calculator at Golden, CO
     date,times,eot,sunrise,sunset
     1/2/2015,7:21:55,-3.935172,-70.699400,70.512721
     1/2/2015,16:47:43,-4.117227,-70.699400,70.512721
@@ -687,7 +687,7 @@ def test_hour_angle():
     eot = np.array([-3.935172, -4.117227, -4.026295])
     hourangle = solarposition.hour_angle(times, longitude, eot)
     expected = (-70.682338, 70.72118825000001, 0.000801250)
-    # FIXME: there are differences from expected NREL SPA calculator values
+    # FIXME: there are differences from expected NLR SPA calculator values
     # sunrise: 4 seconds, sunset: 48 seconds, transit: 0.2 seconds
     # but the differences may be due to other SPA input parameters
     assert np.allclose(hourangle, expected)
diff --git a/tests/test_temperature.py b/tests/test_temperature.py
index e482df6214..e238183600 100644
--- a/tests/test_temperature.py
+++ b/tests/test_temperature.py
@@ -228,7 +228,7 @@ def _read_pvwatts_8760(filename):
     ('pvwatts_8760_roofmount.csv', 49),
 ])
 def test_fuentes(filename, inoct):
-    # Test against data exported from pvwatts.nrel.gov
+    # Test against data exported from pvwatts.nlr.gov
     data = _read_pvwatts_8760(TESTS_DATA_DIR / filename)
     data = data.iloc[:24*7, :]  # just use one week
     inputs = {
diff --git a/tests/test_tracking.py b/tests/test_tracking.py
index 9a7ee98bef..4a0c06bdca 100644
--- a/tests/test_tracking.py
+++ b/tests/test_tracking.py
@@ -345,7 +345,7 @@ def test_calc_axis_tilt():
 
 def test_slope_aware_backtracking():
     """
-    Test validation data set from https://www.nrel.gov/docs/fy20osti/76626.pdf
+    Test validation data set from https://doi.org/10.2172/1660126
     """
     index = pd.date_range('2019-01-01T08:00', '2019-01-01T17:00', freq='h')
     index = index.tz_localize('Etc/GMT+5')