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On-Site Solar

Prescreen All Potential Sites

When considering municipal on-site solar PV, it is important to first understand your portfolio-wide solar energy generation potential. This not only helps you understand the potential impact of your project on reaching your broader renewable energy goals, but also identifies the municipal sites with the greatest solar energy potential.

First, list all municipal buildings, parking lots, and lands (e.g., land near water treatment plants, airports) connected to an electric meter using an organized template such as RMI’s Municipal Solar Site Selection Tool (MSSST) or the Environmental Protection Agency’s (EPA’s) Solar Site Assessment and Utility Data spreadsheet. Next you can use the National Renewable Energy Laboratory’s (NREL’s) PVWatts Calculator tool to determine information to help prioritize sites using the tool’s Draw Your System function (under the System Info tab). If you are using EPA’s spreadsheet, use the site type and address from columns E and F of the spreadsheet to determine the following:

  • Available Area for Solar PV (EPA spreadsheet column R)

    Starting with the largest or most energy-intensive sites, such as water treatment plants and airports, you can quickly identify sites that can host the largest systems. It is important to note, however, that larger ground-mounted systems connected to small loads can only be used to offset the energy from other municipal buildings if meter aggregation is allowed.

  • Shading (EPA spreadsheet column P)

    Note any buildings, trees, or other objects on the south side of the site that may cast shadows on the solar PV system. Additionally, you could put the address in Google’s Project Sunroof to get a better sense for shading concerns.

  • Orientation (EPA spreadsheet column AE)

    Rooftops or lands facing north will not harness as much energy and may not be as economically attractive.

  • Spatial Availability

    Note whether there are HVAC or other rooftop components that might interfere with the installation of a solar system. While these may not make the site unusable, they may restrict the system size.

  • Educational Potential (EPA spreadsheet column J)

    If this is a primary motivation, note sites with potential for community interaction, such as schools or libraries. 

  • Visibility (EPA spreadsheet column AH)

    If this is a primary motivation for on-site solar, note whether a solar project would have low, moderate, or high visibility to the community.

    After compiling this information, narrow down the list of sites for which to collect additional information based on your goals for a total number of sites or total on-site solar capacity. By prescreening the list of sites, you are minimizing the time you will spend on data collection.