Launching PVWATTS v.2 on NREL's Internet Map Server


Please read this guide carefully, then click on the radio button labeled

I HAVE READ THIS DOCUMENT

to proceed to the PVWatts v.2 Internet Map Server site.

You can access the information contained here from the PVWatts v.2 Internet Map Server site
by clicking on the "Help" icon ( ) at the right hand end of the tool bar above the map.


Important!

If you have enabled a pop-up blocker and you want to use the PVWatts tool, you will need to add mapserve2.nrel.gov and this server, rredc.nrel.gov to the blocker's list of sites from which pop-ups are allowed. Check under your browser's Tools menu for pop-up blocker options.


Supported Browsers:

  • PC: The Internet Map Server works best with Microsoft Internet Explorer.

  • Macintosh: On a Macintosh computer you are advised to run the Internet Map Server through Apple Computer, Inc.’s Safari browser.

    • Other browsers partially or fully supporting the IMS on a Macintosh computer are:

      • Microsoft Internet Explorer – fully supported; however, extra explanatory text appears below the layers list in the Layers window (right-hand side of the browser window.)
      • Mozilla Firefox v.2.0.0.11 fully supported
      • Mozilla v.1.7.8 – fully supported.
      • Netscape v.7.2 – fully supported.
How to Use the PVWatts v.2 site on NREL's Internet Map Server:

The tools you will use are all along the top of the screen, as seen in Figure 1, at right. The available tools include:

Toggle between legend list and layer list
Zoom in
Zoom out
Zoom to full extent
Back to last extent
Pan
Identify
Clear selection
Print
Help

  In addition to these standard tools, a custom tool has been added.

    Figure 1. Screen shot of PVWatts v.2 site on NREL's Internet Map Server.
The available layers are all in collapsible groups on the right side of the screen. To hide layers, use your mouse and click on the icon next to the group layer name. This will collapse the layers, allowing you to see which layers are available. Some layers are scale dependent and will not be displayed until you have used the tool and zoomed in to the appropriate pre-defined scale. The tool can only be used when a selected layer is active – to make a layer active, click on this icon in front of the layer name you are interested in, then after clicking on this icon, it will look like this . The active layer will also be indicated below the map with a statement such as: “Counties is Now the Active Layer”.

You can use any of the tools by selecting one with your mouse. If the , , , or tool is selected, the icon will change to display a red box around the tool: e.g., .
The tool can only be used if the Launch PVWATTS v.2 layer is active (Note: To make a layer active, click on this icon in front of the layer name you are interested in.) You can use this tool from the full extent of the map, however if you first Zoom in to the area you are interested in (using the tool), you will more accurately be able to select your area of interest. Once you have selected an area, a separate window will pop up displaying the PVWATTS form. This form, seen in Figure 2, is populated with Cell ID, State, Latitude, Longitude, DC Rating, DC to AC Derate Factor, Array Tilt, Array Azimuth, and Cost of Electricity (2004 data). You can then select your Array Type (fixed tilt, 1-axis tracking or 2-axis tracking) and the click on the calculate button. The PVWATTS calculator will then run and produce a table showing the AC Energy and Cost Savings, as seen in Figure 3.


    Figure 2: The PVWatts user input form.

 


    Figure 3: PVWatts Results table (right) with a table of user input values.

    Figure 2: The PVWatts user input form.     Figure 3: PVWatts Results table (right) with a table of user input values.

Also with this version are the Find Location by Zip Code and by Latitude/Longitude user input boxes, along the bottom of the screen in Figure 1.

To use the Zip Code user input box, you do not have to have the Zip Code Layer active - just type in a 5-digit zip code and click on Go. If an invalid zip code is entered, you will get an error message. When a valid zip code is entered, the map will zoom in and the zip code you entered will be indicated with a gray transparent color and a thicker purple border around the polygon. Note: currently when you use this tool, the zip code layer becomes the active layer so if you want to run the PVWATTS tool, you will have to select the Launch PVWATTS v.2 layer again. To make a layer active, click on this icon in front of the layer name you are interested in.

To use the Latitude/Longitude user input box, type in your numbers (in decimal degrees) making sure you use a minus sign (as an example, 45.0/-111.0) and click on Go. If an invalid Latitude/Longitude is entered, you will not get an error message; nothing will happen. When a valid value is entered, the map will zoom in to the Latitude/Longitude you indicated and be indicated by a purple triangle.

A video tutorial that demonstrates how NREL's dynamic map web sites work is available at NREL's GIS website. Click on the link in the last paragraph.

For questions, comments or suggestions regarding NREL's IMS PVWATTS v.2 site please email the IMS Administrator.