7 September 2023

Solar farms may encourage soil erosion in U.S.


Virginia Tech researchers will analyze erosion risk in the state’s solar installations. In the U.S., the problem is real. But several solutions are available

by Matteo Cavallito


Assessing the impact of large solar farms on soil erosion and stormwater runoff is the goal of a group of researchers from Virginia Tech, or the Polytechnic Institute and State University in Blacksburg, US. The initiative, according to the Cardinal News website, will focus on six large facilities while filling some gap in investigations on the topic.

The research, funded with $3.4 million from the Virginia Department of Environmental Quality, is in fact an alternative approach to studies based on predictive models. Scientists, in fact, aim to collect on-field data over a long enough time frame. The results of the study will allow the models to be adjusted.

On field data collection

“The ability to collect these field data at this scale is a great, unique opportunity,” said Ryan Stewart, associate professor in the School of Plant and Environmental Sciences at Virginia Tech and project leader. In the hopes of the researchers, the six sites identified should represent a wide variety of geographic areas within Virginia and different stages of development, with some plants under construction and others completed.

The survey will measure water quality, runoff and more. The study follows some findings by the Virginia Department of Environment that solar installations would impact the soil by promoting stormwater runoff. And, with it, the loss of sediment and nutrients.

Erosion is a possible fallout of solar farms

The issue has been debated for some time. As of October last year, local broadcaster GPB reported, there were about 140 square kilometers of land covered by solar farms in the state of Georgia. James Cooley, director of the state Department of Natural Resources’ Environmental Protection Division (EPD) operations division, explained that these farms had been built in many cases on sandy soil that was particularly vulnerable to sediment erosion.

In May, the Associated Press reported, a federal jury imposed a $135.5 million penalty on a Tennessee solar company, Silicon Ranch Corporation, and its contractor, Infrastructure and Energy Alternatives. According to the court, the two companies allegedly developed a solar farm by clearing about 4 square miles of land but without installing adequate soil control measures. During rains, the eroded soil allegedly spilled as mud onto nearby private property.

Prevention strategies

All forms of solar panel installation and management should include plans for erosion control, AltEnergyMag magazine said in the past years. The installation of solar panels, in fact, can alter the soil significantly. Erosion, in particular, can be caused by leveling, excavation and burial operations. Finally, the problem can be exacerbated later by wind and rain.

Solutions, however, are not lacking. In fact, again according to the magazine, developers can care for the vegetation of solar parks by taking advantage of the ability of plants and roots to retain water and provide soil stability. Other strategies, such as mulching, the use of geotextiles and drainage, also make it possible to prevent the phenomenon with some effectiveness.