Solar Resource Data (GET /api/solar/solar_resource/v1)

Returns various types of solar data for US locations. The service currently returns data for average Direct Normal Irradiance, average Global Horizontal Irradiance, and average Tilt at Latitude.

Request URL

GET /api/solar/solar_resource/v1.format?parameters

Request Parameters

Parameter	Required	Value	Description
format	Yes	Type: string Default: None Options: json, xml	The output response format.
api_key	Yes	Type: string Default: None	Your developer API key. See API keys for more information.
address	Depends	Type: string Default: None	The address to use. Required if lat/lon not specified.
lat	Depends	Type: decimal Default: None Range: -90 to 90	The latitude for the location to use. Required if address not specified.
lon	Depends	Type: decimal Default: None Range: -180 to 180	The longitude for the location to use. Required if address not specified.

Response Fields

The response is composed of service-related informational fields and the results of the data query.

Field	Value	Description
inputs	Type: collection	The input parameters received in the request.
version	Type: string	The current version of the web service.
errors	Type: array of strings	Any error messages resulting from the request.
warnings	Type: array of strings	Any warning messages resulting from the request.
metadata	Type: collection	Any metadata associated with the request (sources, etc)
outputs	Type: collection	The data outputs from the request. (see output fields for more detail)

Output Fields

The output fields contain the following solar data.

Field	Value	Description
avg_dni	Type: decimal (annual), collection of decimals (monthly)	Average Direct Normal Irradiance: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the resource available to concentrating systems that track the sun throughout the day. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)
avg_ghi	Type: decimal (annual), collection of decimals (monthly)	Average Global Horizontal Irradiance: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the global horizontal resource - the geometric sum of direct normal and diffuse irradiance components, representing total energy available on a planar surface. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)
avg_lat_tilt	Type: decimal (annual), collection of decimals (monthly)	Average Tilt at Latitude: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the resource available to fixed flat plate system tilted towards the equator at an angle equal to the latitude. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)

Field

Value

Description

avg_dni

Type:

decimal (annual),

collection of decimals (monthly)

Average Direct Normal Irradiance: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the resource available to concentrating systems that track the sun throughout the day. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)

avg_ghi

Type:

decimal (annual),

collection of decimals (monthly)

Average Global Horizontal Irradiance: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the global horizontal resource - the geometric sum of direct normal and diffuse irradiance components, representing total energy available on a planar surface. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)

avg_lat_tilt

Type:

decimal (annual),

collection of decimals (monthly)

Average Tilt at Latitude: This data provides monthly average and annual average daily total solar resource averaged over surface cells of 0.1 degrees in both latitude and longitude, or about 10 km in size. The values returned are kWh/m²/day (kilowatt hours per square meter per day). The insolation values represent the resource available to fixed flat plate system tilted towards the equator at an angle equal to the latitude. The data are created using the SUNY Satellite Solar Radiation model (Perez, et.al., 2002). The data are averaged from hourly model output over 12 years (1998-2009). This model uses hourly radiance images from geostationary weather satellites, daily snow cover data, and monthly averages of atmospheric water vapor, trace gases, and the amount of aerosols in the atmosphere to calculate the hourly total insolation (sun and sky) falling on a horizontal surface. The direct beam radiation is then calculated using the atmospheric water vapor, trace gases, and aerosols, which are derived from a variety of sources. Where possible, existing ground measurement stations are used to validate the data. (see http://www.nrel.gov/gis)

Examples

JSON Output Format

GET /api/solar/solar_resource/v1.json?api_key=DEMO_KEY&lat=40&lon=-105

{
  "version": "1.0.0",
  "warnings": [

  ],
  "errors": [

  ],
  "metadata": {
    "sources": [
      "Perez-SUNY/NREL, 2012"
    ]
  },
  "inputs": {
    "api_key": "DEMO_KEY",
    "lat": "40",
    "lon": "-105"
  },
  "outputs": {
    "avg_dni": {
      "annual": 6.06,
      "monthly": {
        "jan": 5,
        "feb": 5.34,
        "mar": 5.94,
        "apr": 6.11,
        "may": 6.36,
        "jun": 7.43,
        "jul": 7.48,
        "aug": 6.65,
        "sep": 6.81,
        "oct": 5.82,
        "nov": 5.11,
        "dec": 4.67
      }
    },
    "avg_ghi": {
      "annual": 4.81,
      "monthly": {
        "jan": 2.5,
        "feb": 3.43,
        "mar": 4.69,
        "apr": 5.69,
        "may": 6.6,
        "jun": 7.25,
        "jul": 7.14,
        "aug": 6.24,
        "sep": 5.35,
        "oct": 3.85,
        "nov": 2.75,
        "dec": 2.19
      }
    },
    "avg_lat_tilt": {
      "annual": 5.82,
      "monthly": {
        "jan": 4.79,
        "feb": 5.4,
        "mar": 6.07,
        "apr": 6.11,
        "may": 6.25,
        "jun": 6.47,
        "jul": 6.58,
        "aug": 6.44,
        "sep": 6.53,
        "oct": 5.71,
        "nov": 4.99,
        "dec": 4.47
      }
    }
  }
}

XML Output Format

GET /api/solar/solar_resource/v1.xml?api_key=DEMO_KEY&lat=40&lon=-105

<?xml version="1.0"?>
<response>
  <version>1.0.0</version>
  <warnings type="array"/>
  <errors type="array"/>
  <metadata>
    <sources type="array">
      <source>Perez-SUNY/NREL, 2012</source>
    </sources>
  </metadata>
  <inputs>
    <api-key>DEMO_KEY</api-key>
    <lat>40</lat>
    <lon>-105</lon>
  </inputs>
  <outputs>
    <avg-dni>
      <annual type="float">6.06</annual>
      <monthly>
        <jan type="float">5.0</jan>
        <feb type="float">5.34</feb>
        <mar type="float">5.94</mar>
        <apr type="float">6.11</apr>
        <may type="float">6.36</may>
        <jun type="float">7.43</jun>
        <jul type="float">7.48</jul>
        <aug type="float">6.65</aug>
        <sep type="float">6.81</sep>
        <oct type="float">5.82</oct>
        <nov type="float">5.11</nov>
        <dec type="float">4.67</dec>
      </monthly>
    </avg-dni>
    <avg-ghi>
      <annual type="float">4.81</annual>
      <monthly>
        <jan type="float">2.5</jan>
        <feb type="float">3.43</feb>
        <mar type="float">4.69</mar>
        <apr type="float">5.69</apr>
        <may type="float">6.6</may>
        <jun type="float">7.25</jun>
        <jul type="float">7.14</jul>
        <aug type="float">6.24</aug>
        <sep type="float">5.35</sep>
        <oct type="float">3.85</oct>
        <nov type="float">2.75</nov>
        <dec type="float">2.19</dec>
      </monthly>
    </avg-ghi>
    <avg-lat-tilt>
      <annual type="float">5.82</annual>
      <monthly>
        <jan type="float">4.79</jan>
        <feb type="float">5.4</feb>
        <mar type="float">6.07</mar>
        <apr type="float">6.11</apr>
        <may type="float">6.25</may>
        <jun type="float">6.47</jun>
        <jul type="float">6.58</jul>
        <aug type="float">6.44</aug>
        <sep type="float">6.53</sep>
        <oct type="float">5.71</oct>
        <nov type="float">4.99</nov>
        <dec type="float">4.47</dec>
      </monthly>
    </avg-lat-tilt>
  </outputs>
</response>

Rate Limits

Standard rate limits apply. No more than 1,000 requests may be made in any hour

Errors

Standard errors may be returned. In addition, the following service-specific errors may be returned:

HTTP Status Code	Description
422	Unprocessable Entity - One or more parameters did not pass validation, or a parameter may be missing. Check the errors section of the response to see how the request should be modified to address the error.

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