Researchers Challenge the CRP Status Quo to Mitigate Fossil Fuels

(University of Illinois at Urbana-Champaign Institute for Sustainability, Energy, and Environment/Phys.Org) ... (A)llocating CRP land for high-yielding energy biomass might eliminate the need for bioenergy crops and food crops to vie for space.

A team led by CABBI Sustainability Theme Leader Madhu Khanna and Ph.D. student Luoye Chen developed an integrated modeling approach to assess the viability of transitioning CRP land in the eastern U.S. to perennial bioenergy crops. Their paper, published in Environmental Science & Technology in January 2021, confirmed that the land-use transition is indeed viable provided that certain key conditions are met.

"As proponents of a safer, more sustainable bioeconomy, we must prioritize displacing fossil fuels," said Khanna, who is also Acting Director of the Institute for Sustainability, Energy, and Environment (iSEE) at the University of Illinois Urbana-Champaign. "As scientists, it is our responsibility to take a thoughtful, innovative approach to mitigating greenhouse gases in a way that will prove beneficial in the long term.

"The transportation and electricity sectors are looking to expand bioenergy production, and it is imperative that the agricultural sector do the same. This necessitates a program wherein bioenergy cropland and food cropland coexist rather than compete."

The CABBI team takes an integrated approach to weighing the costs and benefits of swapping the CRP status quo—uncultivated acreage—for bioenergy, combining the Biofuel and Environmental Policy Analysis Model (BEPAM) with the biogeochemical model DayCent (Daily Time Step Version of the Century Model).

A key component of this study aggregates data from both models to formulate a greenhouse gas (GHG) life-cycle assessment, which calculates the total GHGs mitigated by the process as a whole—from the physical act of planting to the introduction of clean energy into the bioeconomy.

"The full life-cycle assessment really is key to understanding the big-picture results of our research," Chen said. "We take everything into account—the process of actually growing and harvesting the feedstocks, the carbon sequestered in the soil, and the fact that ultimately, we will be displacing fossil fuels with biofuels, and coal-based electricity with bioelectricity.

"Keeping that end result in mind anchors everything else to the ultimate goal of a net positive environmental impact."

The team concluded that converting 3.4 million hectares of CRP land to bioenergy from 2016 to 2030 is economically and environmentally viable—under certain conditions.

The team identified two ideal pairings: 1) landowners receive 100 percent of their original government payments and sell biomass at $75/metric ton; or 2) landowners receive 75 percent of their original payment and sell biomass for $100/metric ton. Ideally, both parties benefit.

Converting CRP land to bioenergy can also result in substantial GHG savings. Previous studies show that a large "soil carbon debt" is liable to accrue at the outset of the venture, during the planting years of miscanthus and switchgrass. However, taking into account the full life-cycle assessment mentioned above, the research team determined that the long-term effects of displacing fossil fuel- and coal-based energy with bioproducts would more than make up for this temporary loss.

Considering landowner income from biomass sales, savings in government payments to maintain existing CRP enrollment, and the monetized benefits of GHG mitigation through displacing fossil fuels (quantified using the "social cost of carbon"), the total net value of converting CRP land to bioenergy could be as high as $28 billion to $125 billion over the 2016-2030 period. READ MORE

Luoye Chen et al, Assessing the Returns to Land and Greenhouse Gas Savings from Producing Energy Crops on Conservation Reserve Program Land, Environmental Science & Technology (2021). DOI: 10.1021/acs.est.0c06133