EPRI: Electric Power Research Institute
Southeastern Solar Research Center
Southeastern Solar Research Center

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Contact Us

Contact EPRI

For website support or for information about EPRI or this project, call 1-650-855-2121, email askepri@epri.com or submit a form to contact EPRI's Customer Assistance Specialists.

About this website

This website was designed and developed by EPRI in collaboration with Southern Company, other member utility companies, and EPRI's Renewable Generation program.

Help: information about this page...

Component View

After reading the overview, try interacting with the comparison chart(s) to learn more about the data's characteristics and trends.

Panels

This page contains several panels: Performance Snapshot, Overview, etc. Tap or click the "?" button in the upper right corner of a panel to see more information about its content.

  1. Site Overview
  2. Total Sky Irradiance (Solar Radiation)
  3. Total Sky (Solar Radiation)

Total Sky Irradiance

Performance Snapshot
Performance Snapshot

This panel may show a sampled measurement (e.g., power) and/or a cumulative measurement (e.g., energy generated).

When the sampled measurement is available, a gauge and trend chart will appear.

When the cumulative measurement is available, its value will be shown over the date range indicated.

Sampled Value (Gauge and Chart)

Total sky irradiance (sum of direct normal irradiance and direct horizontal irradiance)

Total Sky Irradiance
Total Sky Irradiance (W/m²)
Overview
Enlarge Image

Total sky irradiance is the sum of direct normal irradiance and diffuse horizontal irradiance. It is the irradiance seen if a pyranometer were mounted to a tracking system that moves with the sun as it travels across the sky. The total sky irradiance is the highest measured irradiance possible at any point in the day. It is indicative of the irradiance seen in the plane of the most optimal tilt and rotation (azimuth) at that moment.

Measurement Source

The total sky irradiance is the sum of the direct normal and diffuse horizontal irradiances, measured separately.

Time Series Profile
Time Series Profile

Chart (or charts) shows trends for a specific component. Each data point represents an aggregated value for the time interval indicated (e.g., 15-minute average).

Chart Navigation

Tap or click on the chart titles (if more than one shown) to switch the view between charts. The title of the displayed chart is highlighted in orange.

Zoom and Pan

To zoom in on and get a closer view of a plot area in a chart:

  • On a touchscreen: Use two fingers to spread apart (expand) the plot area, then use one finger to slide the plot area left and right.
  • Using a mouse: Click and drag to select a section of the plot area, then hold down the Shift key while dragging left and right.
  • Tap or click on the "Reset zoom" button to return the chart to its original size.

Toggle Legend Items

Tap or click on a legend item (if more than one shown) to hide or show its data in the plot area.

Measurements Plotted

Chart (or charts) includes one or more of the following measurements (indicated in the legend or title):

  • Total sky irradiance (sum of direct normal irradiance and direct horizontal irradiance)

Preset Date Ranges

Custom Date Range

to
Data are available beginning 5/1/2014. Clear the end date to view the most recent data available.
Tip: click "?" (next to the Edit button) to learn how to interact with the chart.

Download Chart Data

Save chart data as a comma-separated values (CSV) file:
Note: timestamps (first column in the CSV file) are adjusted to your computer's time zone and represent the beginning of each interval.
Warning: downloading data is intended for desktop and laptop computers. This feature may not work for smartphones or tablets.
TOTAL SKY IRRADIANCE
Daily Performance
Daily Performance

Chart (or charts) shows trends for a specific component. Each data point represents an aggregated value for the date indicated.

Chart Navigation

Tap or click on the chart titles (if more than one shown) to switch the view between charts. The title of the displayed chart is highlighted in orange.

Zoom and Pan

To zoom in on and get a closer view of a plot area in a chart:

  • On a touchscreen: Use two fingers to spread apart (expand) the plot area, then use one finger to slide the plot area left and right.
  • Using a mouse: Click and drag to select a section of the plot area, then hold down the Shift key while dragging left and right.
  • Tap or click on the "Reset zoom" button to return the chart to its original size.

Toggle Legend Items

Tap or click on a legend item (if more than one shown) to hide or show its data in the plot area.

Measurements Plotted

Chart (or charts) includes one or more of the following measurements (indicated in the legend or title):

  • Total sky irradiance (sum of direct normal irradiance and direct horizontal irradiance)

Preset Date Ranges

Custom Date Range

to
Data are available beginning 5/1/2014. Clear the end date to view the most recent data available.
Tip: click "?" (next to the Edit button) to learn how to interact with the chart.

Download Chart Data

Save chart data as a comma-separated values (CSV) file:
Note: dates (first column in the CSV file) are based on the site's geographic location, which may be different from your computer's time zone.
Warning: downloading data is intended for desktop and laptop computers. This feature may not work for smartphones or tablets.
TOTAL SKY IRRADIANCE
Monthly Performance
Monthly Performance

Chart (or charts) shows trends for a specific component. Each data point represents an aggregated value for the month indicated.

Chart Navigation

Tap or click on the chart titles (if more than one shown) to switch the view between charts. The title of the displayed chart is highlighted in orange.

Zoom and Pan

To zoom in on and get a closer view of a plot area in a chart:

  • On a touchscreen: Use two fingers to spread apart (expand) the plot area, then use one finger to slide the plot area left and right.
  • Using a mouse: Click and drag to select a section of the plot area, then hold down the Shift key while dragging left and right.
  • Tap or click on the "Reset zoom" button to return the chart to its original size.

Toggle Legend Items

Tap or click on a legend item (if more than one shown) to hide or show its data in the plot area.

Measurements Plotted

Chart (or charts) includes one or more of the following measurements (indicated in the legend or title):

  • Total sky irradiance (sum of direct normal irradiance and direct horizontal irradiance)

Preset Date Ranges

Custom Date Range

to
Data are available beginning 5/1/2014. Clear the end date to view the most recent data available.
Tip: click "?" (next to the Edit button) to learn how to interact with the chart.

Download Chart Data

Save chart data as a comma-separated values (CSV) file:
Note: dates (first column in the CSV file) are based on the site's geographic location, which may be different from your computer's time zone.
Warning: downloading data is intended for desktop and laptop computers. This feature may not work for smartphones or tablets.
TOTAL SKY IRRADIANCE
Image for Total Sky Irradiance