Posted on 17 December 2024 by BaerbelW

On November 1, 2024 we announced the publication of 33 rebuttals based on the report "Rebutting 33 False Claims About Solar, Wind, and Electric Vehicles" written by Matthew Eisenson, Jacob Elkin, Andy Fitch, Matthew Ard, Kaya Sittinger & Samuel Lavine and published by the Sabin Center for Climate Change Law at Columbia Law School in 2024. Below is the blog post version of rebuttal #7 based on Sabin's report.

Ambitious solar deployment would utilize a relatively small percentage of U.S. land when compared to the land currently being used for agriculture. The Department of Energy estimated that total U.S. solar development would take up roughly 10.3 million acres in a scenario in which cumulative solar deployment reaches 1,050–1,570 GW by 2050, the highest land-use scenario that DOE assessed in its 2021 Solar Futures Study¹. If all 10.3 million acres of solar farms were sited on farmland, they would occupy only 1.15% of the 895,300,000 acres of U.S. farmland as of 2021². However, many of these projects will not be located on farmland.

Furthermore, solar arrays can be designed to allow, and even enhance, continued agricultural production on site. This practice, known as agrivoltaics, provides numerous benefits to farmers and rural communities, especially in hot or dry climates³. Agrivoltaics allow farmers to grow crops and even to graze livestock such as sheep beneath or between rows of solar panels⁴ (also Adeh et al. 2019). When mounted above crops and vegetation, solar panels can provide beneficial shade during the day (Williams et al. 2023). Multiple studies have shown that these conditions can enhance a farm’s productivity and efficiency (Aroca-Delgado et al. 2018). One study found, for example, that "lettuces can maintain relatively high yields under PV" because of their capacity to calibrate "leaf area to light availability" (Marrou et al. 2013). Extra shading from solar panels also reduces evaporation, thereby reducing water usage for crops by around 14-29%, depending on the level of shade (Dinesh & Pearce 2016). Reduced evaporation from solar installations can likewise mitigate soil erosion. Solar farms can also create refuge habitats for endangered pollinator species, further boosting crop yields while supporting native wild species⁵. Overall, agrivoltaics can increase the economic value of the average farm by over 30%, while increasing annual income by about 8%. Farmers in other countries have begun implementing agrivoltaic systems (Tajima & Iida 2021). As of March 2019, Japan had 1,992 agrivoltaic farms, growing over 120 different crops while simultaneously generating 500,000 to 600,000 MWh of energy⁶.

Furthermore, the argument that solar development will imperil the food supply is belied by the fact that tens of millions of acres of farmland are currently being used to grow crops for other purposes, such as the production of corn ethanol. Currently, roughly 90 million acres of agricultural land in the United States is dedicated to corn, with nearly 45% of that corn being used for ethanol production⁷. Solar energy could provide a significantly more efficient use of the same land. Corn-derived ethanol used to power internal combustion engines has been calculated to require between 63 and 197 times more land than solar PV powering electric vehicles to achieve the same number of transportation miles⁸. If converted to electricity to power electric vehicles, ethanol would still need roughly 32 times more land than solar PV to achieve the same number of transportation miles. And even when accounting for other energy by-products of ethanol production, solar PV produces between 14 and 17 times more gross energy per acre than corn. The figure below contrasts the land use requirements of solar PV with dedicated biomass and other energy sources. Whereas dedicated biomass consumes an average of 160,000 hectares of land per terawatt-hour per year, ground-mounted solar PV consumes an average of 2,100 (Lovering et al. 2022).

Figure 4: Average land-use intensity of electricity, measured in hectares per terawatt-hour per year. Source: U.S. Global Change Research Program (visualizing data from Jessica Lovering et al. 2022).

Finally, while solar installations, like any infrastructure projects, will inevitably have some adverse impacts, the failure to build the infrastructure necessary to avoid climate change poses a far more severe threat to agricultural production. Climate change already harms food production across the country and globe through extreme weather events, weather instability, and water scarcity⁹. The most recent Intergovernmental Panel on Climate Change (IPCC) report forecasts that climate change will cause up to 80 million additional people to be at risk of hunger by 2050¹⁰. A 2019 IPCC report forecasted up to 29% price increases for cereal grains by 2050 due to climate change¹¹. These price increases would strain consumers globally, while also producing uneven regional effects. Moreover, while higher carbon dioxide levels may initially increase yield for certain crops at lower temperature increases, these crops will likely provide lower nutritional quality. For example, wheat grown at 546–586 parts per million (ppm) CO₂ has a 5.9–12.7% lower concentration of protein, 3.7–6.5% lower concentration of zinc, and 5.2–7.5% lower concentration of iron. Distributions of pests and diseases will also change, harming agricultural production in many regions. Such impacts will only intensify for as long as we continue to burn fossil fuels¹².

Footnotes:

[1] U.S. Dep’t. Energy Solar Energy Technologies Office, Solar Futures Study, U.S. Dep’t. Energy Office of Energy Efficiency & Renewable Energy, at vi, 179 (Sep. 2021)

[2] U.S. Dep’t. of Agriculture, Farms and Land in Farms: 2021 Summary, 4 (Feb. 2022)

[3] Eric Larson et al., Net-Zero American: Potential Pathways, Infrastructure, and Impacts: Final Report, Princeton University, 247 (Oct. 29, 2021)

[4] Michael Nuckols, Considerations when leasing agricultural lands to solar developers, Cornell Small Farms (Apr. 6, 2020)

[5] Empowering Biodiversity on Solar Farms, University of Georgia College of Agricultural and Environmental Sciences, 2020

[6] This is enough energy to power roughly 50,000 American households. U.S. Energy Information Admin., Use of energy explained: Energy use in homes (last visited March 25, 2024)

[7] Feed Grains Sector at a Glance, U.S. Dep’t of Agriculture (last updated Dec. 21, 2023)

[8] Paul Mathewson & Nicholas Bosch, Corn Ethanol vs. Solar: Land Use Comparison at 1 (Clean Wisconsin 2023)

[9] Alisher Mirzabaev et al. (2023), Severe climate change risks to food security and nutrition, 39 Climate Risk Management 100473, 3, (“Adverse consequences are already occurring, and the chances of their exacerbation under climate change are high”); Food and Agriculture Organization of the United Nations, Climate Change and Food Security: Risks and Responses at ox-xii (2015); Agriculture and Climate, U.S. Env’t. Prot. Agency, (last visited March 25, 2024); Laura Reiley & Kadir van Lohuizen, Climate change is pushing American farmers to confront what’s next, Wash. Post, Nov. 10, 2023

[10] IPCC AR6 WGII, Climate Change 2022: Impacts, Adaptation, and Vulnerability (2022)

[11] Chiekh Mbow et al., Food Security, in Climate Change and Land: an IPCC special report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gases fluxes in terrestrial ecosystems, Exec. Summary, Intergovernmental Panel on Climate Change (2019).

[12] Causes and Effects of Climate Change, United Nations (last visited March 25, 2024).

Skeptical Science sincerely appreciates Sabin Center's generosity in collaborating with us to make this information available as widely as possible.