The Challenge

Carbon dioxide (CO₂) emissions make up more than 80 percent of the greenhouse gases that can alter global weather patterns, change the growing season for food crops, and threaten coastal communities. According to a 2017 emission report, U.S. agriculture contributes nearly 10 percent (620 million metric tons) of these emissions.

In addition, farmers are hard hit by weather impacts, as well as changing tariffs. Commercial crops grown on marginal land yield a further loss because the return on investment in those plots is often minimal or negative.

Fuels and products made from biomass can reduce the amount of agriculture-related carbon emitted to the atmosphere by sequestering carbon in the soil and displacing the CO₂ emissions from crops that have large carbon footprints.

Strategically placing native grasses, such as switchgrass, in unproductive marginal land sequesters carbon and improves soil health. This can also help farmers reap extra income and improve land management. Switchgrass biomass sequesters carbon in the soil that can be sold to pro-low-carbon companies such as Dannon, General Mills, etc., generating an additional revenue stream for farmers. However, identifying locations to produce these bioenergy crops and measuring the potential environmental and economic benefits can be challenging.

The Approach

Argonne researchers developed an integrated framework to assess the economic and environmental benefits of converting marginal land — land that has low productivity or is environmentally sensitive – in Illinois from traditional crops like corn and soybeans to switchgrass.

Argonne’s framework employed a combination of the following elements to estimate the biomass yield and soil carbon sequestration potential of such a switch:

• Economic analysis of profit maximization and spatial optimization under various scenarios
• Spatial analysis of location-specific environmental variables
• Models to simulate energy and environment interaction

The Results

Argonne found that converting 93,000 hectares (ha) of Illinois’ marginal land to produce biomass could generate a net profit of around $7 million for landowners and increase soil organic carbon levels by 0.1 to 0.41 metric tons/ha^-1/yr^-1.

Assuming a potential compensation of $15/metric ton of CO₂ for carbon sequestration, Argonne found that converting 95,000-143,000 ha of land from traditional crops to biomass would generate net profits of $14 to $21 million for landowners.

While the sequestered carbon pays off for farmers through carbon credits and increased soil productivity in the long run, the global benefits are even greater. Bioenergy crop production on marginal plots can produce biomass to support the bioeconomy, preventing food-fuel conflicts and producing ecosystem services that can mitigate climate change and contribute to environmental sustainability.