EESI Intern Analyzes Solar Energy Potential of Georgia’s Contaminated Lands | Article

Solar power has grown substantially over the past decade as installed costs have fallen and solar panel efficiencies have steadily risen. My home state of Georgia has capitalized on these improvements, and its installed solar capacity has grown rapidly to over 2,600 megawatts (MW) in 2020, with the Solar Energy Industries Association now labeling Georgia a “Top 10 Solar State.” For my graduate capstone at the Georgia Institute of Technology, I researched new opportunities to further grow the state’s solar industry, but I wasn’t sure what new contribution I could add. At the time, I was researching utility-scale solar with the Drawdown Georgia project, a multi-university climate research project, and I wanted to identify an issue that could complement my research. One day, while driving near my home, I passed a local landfill, and I had a eureka moment: What if our landfills housed solar panels?

It turns out I was a decade late to this idea. Many states, particularly those in New England, have converted their contaminated lands into renewable energy sites, mostly solar power facilities. The Environmental Protection Agency (EPA) even has its own program focused on using contaminated lands for renewable energy, The RE-Powering America’s Land Initiative. The RE-Powering Initiative states that contaminated lands have numerous advantages that should encourage renewable energy development: nearby existing infrastructure, lower land costs, available tax incentives, and more. After some quick research, I learned that although landfill solar is nothing new, it has barely been implemented in southern states, including Georgia. With this in mind, I decided to research which of Georgia’s contaminated sites could be good options for solar power sites and what incentives could make landfill solar appealing in Georgia.

The RE-Powering Initiative had already completed some of the work for me. Analysts at the EPA have identified contaminated sites, including landfills, Corrective Action sites, Superfund sites, and brownfields, and have estimated the already installed solar capacity at each site using property data. However, the RE-Powering Initiative’s analysis omits several key considerations, such as the terrain slope, which influences the size of solar arrays. In the first part of my capstone, I conducted a rudimentary terrain analysis in Google Earth Pro to better estimate the acreage of usable land for solar PV at each contaminated site, and I applied a metric of 8 acres/MW instead of the RE-Powering Initiative's optimistic 4.5 acres/MW. Focusing on small utility-scale solar PV, I eliminated sites that were unable to support a solar PV system of at least 2 MW.

With the site information in hand, I used the National Renewable Energy Laboratory’s (NREL) System Advisor Model (SAM) tool to design each qualifying solar PV system and determine whether they were worth their high upfront costs. The SAM tool calculated each project’s annual energy production, costs, and electricity revenues throughout its lifetime. Through the SAM tool’s parametric analysis function, I inserted relevant state and federal financial conditions and included different policy incentives to see how these factors affect the net present value (NPV) of the designed systems. Lastly, I combined the energy production outputs from SAM with data from Georgia Tech’s National Energy Modeling System (NEMS) program to loosely predict the carbon emissions reduction and air quality benefits from each solar PV system.

From my research, I determined that dozens of contaminated sites across Georgia are large enough for small utility-scale solar PV systems. The City of Tifton Landfill, for example, could contain a solar power system of almost 7.5 MW, and my SAM simulations predict the system could produce almost 340 million kilowatt hours over its lifetime, reducing carbon emissions by about 153,000 tons. While many of these sites could contain profitable solar power systems, it is unlikely Georgia Power or other solar developers will invest in landfill solar in the near future.

Solar power developers in Georgia have plenty of flat farmland to choose from for their energy projects, unlike in northern states, and the state lacks policy incentives that encourage projects on contaminated lands and increase their economic feasibility. Many northern states provide property and sales tax exemptions, a clear permitting process, or limited liability protections to encourage new solar PV projects on contaminated lands. Other states, such as Massachusetts, have programs that provide more generous policy incentives, such as feed-in-tariffs, to specifically encourage projects on contaminated lands. With location-based incentives and carbon taxes, renewable energy projects on contaminated lands would seem even more worthwhile.

My research suggests contaminated lands represent an additional renewable energy investment opportunity for Georgia and other southern states, and with new policy incentives, these sites can be made even more competitive for locating renewable energy systems. Considering contaminated lands for renewable energy development is worthwhile, especially as the United States emerges from the current economic crisis. With the growing urgency to mitigate climate change, our energy system will continue to evolve as policy priorities change, and one day, solar power systems on contaminated lands may be common across the entire country.

Author: Hamilton Steimer