Alliant Energy EPRI: Electric Power Research Institute
Madison Solar Demonstration Project
Madison Solar Demonstration Project

Site Settings

PV Module Temperature
Outdoor Air Temperature
Wind Speed
Cumulative Precipitation
Precipitation Rate
Feels Like Temperature
Slideshow Speed: Home Page and Image Gallery
Automatically advance to the next image:
Tip: pause a slideshow by clicking or advancing images manually.

 

Alternate Display Modes

Full Screen Mode
When using a desktop or laptop computer, you may be able to toggle full screen mode. Chrome, Firefox, and Internet Explorer: press [F11]. Edge: press [Shift]+[Windows key]+[Enter]. Safari: press [Control]+[Command]+[F]. Your browser may also have a menu option to view full screen.
Billboard Mode
Entering this mode will automate the entire website, advancing through a predefined set of pages at specific time intervals. This mode is intended for kiosks or displays where user interaction is prohibited or not feasible. Do not use billboard mode with smartphones or tablets. Click here to enter billboard mode.

Contact Us

Contact Alliant Energy

For information about Alliant Energy or this project, call 1-800-ALLIANT (1-800-255-4268). Please contact EPRI for website support.

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 Alliant Energy, EPRI's Integration of Distributed Energy Resources and Solar programs, and EPRI's Power Delivery and Generation sectors.

Help: information about this page...

Watch Time-Lapse Videos

Tap or click the play button (may be overlaid on the video image). Most browsers provide an option to enable full-screen playback.

No Audio

The videos do not have audio.

Video Compatibility

Most devices (manufactured within the past 5 years) and popular web browsers should play the videos. Please contact EPRI if you have technical difficulties with video playback.

Download Videos

To download a video for offline use, right-click on a video and choose "Save video as..." when using a computer. Saving videos may not be supported on mobile devices.

Sky Images During the Solar Eclipse (Aug 21, 2017)

Time-lapse footage* of the southern sky during the August 21 solar eclipse. The combination of overcast conditions and the camera's automatic exposure masks the visual effect of the eclipse. The camera is facing upward and the video has been cropped to show only the southern sky. (*5-second snapshots replayed at 60 frames per second)

Video duration 32 sec.

min:sec
0:00 Partial eclipse begins at 11:51 AM (US Central)
0:15 Peak obscuration (85%) at 1:15 PM (US Central)
0:32 Partial eclipse ends at 2:38 PM (US Central)
Single-Axis Tracker During the Solar Eclipse (Aug 21, 2017)

Time-lapse footage* of the single-axis tracker PV system during the August 21 solar eclipse. Because of overcast conditions, both the irradiance and power output generally remain at low levels throughout the day. The solar eclipse does reduce the power output significantly during the 2:00 PM CDT hour, which is illustrated in the graph. The camera is facing eastward. (*15-minute snapshots interpolated to 1-minute intervals and then replayed at 15 frames per second)

Video duration 13 sec.

min:sec
0:04 Partial eclipse begins at 11:51 AM (US Central)
0:06 Peak obscuration (85%) at 1:15 PM (US Central)
0:07 Partial eclipse ends at 2:38 PM (US Central)
Sun Tracker on a Clear Day (Feb 3, 2017)

Time-lapse footage* of a clear day in winter shows high direct normal irradiance (DNI), low diffuse horizontal irradiance (DHI), and a depressed curve for global horizontal irradiance (GHI) due to the sun's lower elevation angle. The camera is facing west and traffic on Interstate 90 is visible in the distance. (*1-minute snapshots replayed at 20 frames per second)

Video duration 48 sec.

min:sec
0:09 Sunrise at 7:10 AM (US Central)
0:25 Solar noon (sun reaches highest point in the sky)
0:39 Sunset at 5:15 PM (US Central)
0:40 Sun tracker resets for the next day
0:47 Venus appears in the western sky
Dual-Axis Tracker on a Partly-Sunny Day (Feb 5, 2017)

Time-lapse footage* of the dual-axis tracker PV array shows the morning hours are mostly overcast, while the afternoon hours are mostly sunny. Notice that plane-of-array (POA) irradiance is often the highest irradiance component. This is expected because the dual-axis tracker adjusts its rotation and tilt to find the brightest spot in the sky - within its mechanical limits. The camera is facing north. (*1-minute snapshots replayed at 20 frames per second)

Video duration 36 sec.

min:sec
0:03 Sunrise at 7:10 AM (US Central)
0:17 Plane-of-array irradiance (POA) exceeds 1000 W/m² due to cloud enhancement as solar radiation is reflected from edges of clouds. Also notice the diffuse irradiance component (DHI) is higher at this moment.
0:20 Plane-of-array irradiance remains close to 1000 W/m² around solar noon
0:33 Sunset at 5:15 PM (US Central)
0:34 Tracker resets for the next day
Snow Melt on Southeast Fixed-Tilt Array (Dec 5, 2016)

Time-lapse footage* shows snow melting and sliding off of the southeast-facing fixed-tilt PV array. Weather conditions were overcast on this day, yet the higher tilt angle (35°) allowed snow to slide off quite effectively. The camera is facing north. (*15-minute snapshots interpolated to 1-minute intervals and then replayed at 20 frames per second)

Video duration 42 sec.

min:sec
0:03 Sunrise at 7:15 AM (US Central)
0:11 Peak irradiance on this overcast day is about 150 W/m² (15% of "1 sun")
0:22 All snow has been shed except for 1 stubborn section that appears to be held in place by the solar panel's frame or mounting clips.
0:31 Sunset at 4:20 PM (US Central)