Carbon negative biofuels can build soil and rural prosperity

Guest Column | Chuck Hassebrook, David Laird and Jill Euken

Iowa has the opportunity to play a leading role in meeting two critical challenges for averting the worst effects of climate change. Fossil fuels must be replaced in aviation, cargo ships and other difficult to electrify forms of transportation. And carbon must be removed from the atmosphere and stored in soil as organic matter.

Recent research by the Iowa State University (ISU) Bioeconomy Institute offers a compelling new pathway for accomplishing both. With supportive federal policy, that pathway can create jobs across rural Iowa and economic opportunity for farmers.

That pathway is the Pyrolysis-Biochar-Bioenergy Platform, which produces biofuel and biochar by heating crop residue, grass, wood or other forms of biomass in the absence of oxygen. Biochar is a form of charcoal that lasts hundreds to thousands of years in soil as it builds soil health. ISU analysis demonstrates that the biochar can sequester more carbon in soil than is released by producing and burning the biofuel.

Biochar first drew scientific notice when dark, fertile terra preta soils in the Amazon were found to contain charcoal added over centuries by Indigenous people. The added biochar made rich farmland out of infertile, rainforest soils. Biochar from prairie fire is also a critical element in the fertile, carbon-rich soils in Iowa.

Research demonstrates that biochar can improve soil health, reduce soil nitrous oxide emissions, increase soil water holding capacity, build new soil organic matter and improve crop yields on eroded and sandy soils as it removes carbon dioxide from the atmosphere.

Biofuel and biochar can be produced from crop residue that would otherwise decompose and release its carbon to the atmosphere in a few years. Removing a portion of crop residue and returning the longer-lived biochar produces a net increase in soil carbon. That creates an opportunity for farmers to sell excess crop residue while maintaining soil organic matter and health.

A pyrolysis-biochar-bioenergy industry would also create a market for perennial grasses such as switchgrass grown on unproductive farmland. Perennial grass would help restore eroded or degraded soil by building organic matter and provide an alternative crop for farmers on their least profitable acres.

Finally, biochar offers farmers an opportunity to sell high-value carbon credits without the concerns about the “additionality” and “permanence” that has impeded the development of agriculture carbon markets.

Nevertheless, we won’t realize the potential of the pyrolysis and biochar pathway to carbon negative biofuels without investing in its development. U.S. Department of Energy (DOE) grant programs should place greater emphasis on coproduction of biochar and biofuel. DOE already makes matching grants for pilot and demonstration facilities that produce other types of cellulosic biofuels. Extending those grants to pyrolysis-biochar-bioenergy facilities could help jump start the industry.

There is also a need for increased research on the use of biochar in soil. Findings to date have been inconsistent, because biochar has varying characteristics depending on the feedstock from which it is produced and the temperatures at which is processed. Additionally, its effects vary in different soils and conditions.

USDA should launch a ten-year coordinated, multisite research program to determine how to manage biochar for different soils, crops, climates and management systems to improve soil health, increase agricultural productivity and efficiently sequester carbon. In addition, USDA should develop a practical and economical method for assigning carbon credits for applying biochar to soil.

The emerging pyrolysis-biochar-bioenergy industry is an exciting opportunity for Iowa farmers to create jobs and opportunity in their communities and to become heroes in the global fight against climate change. But it won’t happen without concerted action by federal policymakers.

Chuck Hassebrook of Lincoln, NE is the Leader of the Biochar Policy Project of the National Center for Appropriate Technology. David Laird is a professor emeritus (retired) of soil science at Iowa State University and president of N-Sense, Inc. an Ames based ag-technology startup company. Jill Euken farms with her family in SW Iowa and serves on the Boards of Ag Ventures Alliance and Southwest Iowa Renewable Energy (SIRE).