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The Grid Data Calculator (Version 2) will no longer be supported after June 2014.

Please use the most current version PVWatts®.

Grid Data Calculator (Version 2)

The Grid Data Calculator (Version 2) allows users to select a photovoltaic (PV) system location in the United States from an interactive map.

The Grid Data Calculator uses hourly typical meteorological year weather data and a PV performance model to estimate annual energy production and cost savings for a crystalline silicon PV system. It allows users to create estimated performance data for any location in the United States or its territories by selecting a site on a 40-kilometer (km) gridded map. The Grid Data Calculator considers data from a climatologically similar typical meteorological year data station and site-specific solar resource and maximum temperature information to provide PV performance estimation.

In this version, performance is first calculated for the the nearest TMY2 location and then translated to the desired 40-km grid cell location. The translation process uses grid cell monthly values of solar radiation and meteorological parameters. Because the translation process uses monthly values, hourly values of PV performance are not available for 40-km using Grid Data Calculator.

The Grid Data Calculator provides easy access to both datasets. This application, built on ESRI Flex Viewer, utilizes an interactive web mapping interface that allows you to query both data sets simultaneously for any specified location. The screenshot below illustrates the various data sets as they are displayed in the Grid Data Calculator. Station locations are indicated by a black cross with a yellow center and a 40-km solar resource grid (yellow to red squares) is overlaid on top of a street map of the United States.

Screenshot of the PVWatts Viewer

Base Map Viewing Options

You have two viewing options: road base map or satellite base map. A road map is the default base map. You can change the base map at anytime. To change the base map, use these icons located in the upper right corner:

Icon that Represents the Road Map View Road Map - Click on this icon to display a road map as your base map.
Icon that Represents the Satellite Map View Satellite Map - Click on this icon to display a satellite view as your base map.

Grid Visibility/Transparency

A grid visibility/transparency check box and slider in the upper right corner allows you to set the levels of transparency for easier viewing of underlying reference data. By default, it is set to 50%.

Panning and Zooming

Panning is available by just clicking and dragging on the map. You can zoom by using the Zoom Full icon in the upper part of the Viewer, by using the zoom slider, or by using the scroll wheel on your mouse while hovering over any portion of the map. Note: To allow for easy drawing, panning is disabled while using the draw tools.

The Zoom Full button  Zoom Full - Click on this icon to return the map to its initial zoom level.
The Zoom Slider button Zoom Slider - Click the plus or minus to zoom in or out, drag the slider to the desired zoom level, or click directly on the desired zoom level.

PVWatts Tool

If not already visible, this icon will open the PVWatts Tool as shown below:

The PV Watts Tool button PV Watts Tool - If not already visible, clicking on this icon will open the PVWatts Tool as shown below:
Screenshot of the PVWatts Tool window

Tools Menu

Many additional tools are available to you through the tools menu. To access the menu, click the Tools icon shown below. A menu of available tools will appear. Clicking on a tool will activate it, opening a new panel on the right side of the map. Clicking the green arrow in the upper right of the tool's panel will minimize it and the selected tool will remain active. If minimized, clicking the tool's icon will restore the tool's panel. Note: Some tools have specific actions which will change the functionality of the mouse. The restore the default PV Watts tool, click the PVWatts tool icon on the main toolbar (see above).

Tools Menu button Tools Menu - If not already visible, clicking on this icon will open the PVWatts Tool as shown below:
Help button Help - Displays this page.
Overview button Overview Map - Displays an overview map that helps you locate your current selection on a larger map. Drag the red box in the overview map to change your location.
Print button Print - Prints the map. Optional fields allow you to declare a title and subtitle for your map.
Locate button Locate - Select a specific location to display by ZIP code, address or coordinates. Locating by ZIP code will select the center of the ZIP code.
Draw button Draw - Customize your map and draw attention to specific areas with a variety of drawing and labeling tools.

For more information, see PVWatts Version 2 - Enhanced Spatial Resolution for Calculating Grid-Connected PV Performance.

To use the PVWatts Grid Data (Version 2) calculator, see: