Partnering with Esri—the global leader in location intelligence—The Ray has configured a right-of-way (ROW) solar mapping tool to help agencies quickly analyze how economically viable ROW locations might be for solar array placement. The mapping tool can also produce precise configurations of solar arrays on all ROW types, utilizing state Department of Transportation (DOT) datasets. Built using Esri’s ArcGIS software suite, the tool includes advanced 3D modeling, solar radiation calculations based on elevation and surface, as well as viewshed analysis.

Media Spotlight: Creativity fuels record growth in solar power across U.S., NBC Bay Area

“According to a trade industry report, the U.S. added more solar power in 2023 than ever before—enough electricity for 24 million people. As solar expands, states are getting creative with how the panels can do more than just generate power. National climate reporter Chase Cain shows us some of the country’s most innovative solar solutions — from Project Nexus in California to Central Florida’s expressways.”


For land-use, planning and transportation agencies, our tool is revolutionary because it provides estimated projections of energy generation and its associated economic values. Consisting of a three-step analysis process, the first step is the inclusion and exclusion analysis that identifies potential solar installation sites. In addition, the solar potential and electricity values for those sites are also calculated. The second step is the suitability analysis to prioritize sites for solar installation. This step ranks the first analysis results based on solar radiation, aspect, and slope information. The final step is 3D modeling to visualize solar panel arrays on a selected site and calculate more accurate potential energy generation and carbon reduction values based on the number of solar panels we add to the site.

In 2023, The Ray’s GIS team completed two nationwide railroad analyses, each spanning more than 20 states. We also conducted 11 statewide DOT and rail ROW analyses in Arizona, Colorado*, Delaware, Georgia, Maine, Maryland, Minnesota, New Hampshire, and North Carolina*. Additionally, 11 small-scale analyses were performed for Austin, TX, CalTrans D4, D7, D8, and D11, Charleston County, SC, Northwest Parkway, CO, Oregon’s excess and surplus parcels, PA Turnpike*, Serenbe, GA and SunTrax, FL.

*Quality assurance and quality control (QA/QC) analysis projects

Our analyses demonstrate the passive capacity and untapped power that highway and rail ROW possess. At the close of 2023, the combined data from the land surveyed on behalf of our partners reveals that there are a total of 817,217 suitable acres for solar ROW installation. This can be converted into 163,449 megawatts (MW) of energy and 259,465,822 megawatt-hours per year (MWh/yr). The estimated energy value is astounding—more than $31 trillion dollars per year. Moreover, the carbon dioxide equivalent (CO2e) is 183,878,870 metric tons.

Partnership Spotlight: The Maine Department of Transportation (MaineDOT) installed three solar energy parks at the Augusta airport and at Exits 109 and 112 alongside Interstate 95, producing clean energy for the state capitol complex. This megawatt win is projected to save Maine $7.2 million in energy costs over the next two decades. Generating approximately 8.5 MW, the solar arrays will cut the state’s emissions by 2,000 metric tons per year. Completing this multi-year solar ROW project is not only good for the environment but it also saves taxpayers money with zero-emission electricity.

“The deal that MaineDOT has negotiated is a gold standard for other states to try to follow. For example, MaineDOT has taken roadside parcels, which have cost them money over the decades to maintain, and they have turned that land into a revenue-generating opportunity,” explained Executive Director, Allie Kelly.