‘Diesel nut’ development brings Texas A&M AgriLife, Chevron together

Peanut oil powered the world’s first diesel engine when it was premiered by Rudolf Diesel at the World Exposition in Paris in 1900. Now, a collaboration between Chevron and Texas A&M AgriLife is reviving the use of peanuts as a renewable feedstock for diesel fuel with a lower carbon intensity.

Carbon intensity is the energy expended to produce a product, including production inputs such as water, pesticide and fertilizer, and how much net carbon that process adds to the atmosphere. Lower carbon intensity is important in developing sustainable agricultural practices.

The five-year, multi-million-dollar project will be led by John Cason, Ph.D., a Texas A&M AgriLife Research peanut breeder at Stephenville. Development of the “diesel nut” will be multi-pronged and will include estimating economic feasibility, advancing existing high-oil peanut germplasm and developing new, low-input peanut lines for the renewable diesel industry.

Co-leaders on the project are Luis Ribera, Ph.D., Texas A&M AgriLife Extension Service economist and director of Texas A&M’s Center for North American Studies, Bryan-College Station; Bill McCutchen, Ph.D., center director for Texas A&M AgriLife Research and Extension Center, Stephenville; and David Baltensperger, Ph.D., head of the Texas A&M Department of Soil and Crop Sciences.

Cliff Lamb, Ph.D., director of AgriLife Research, Bryan-College Station, said this collaboration with Chevron gives AgriLife Research scientists a chance to develop peanuts that have a greater oil content and are better adapted to dryer climates — ultimately creating a more resilient agricultural system.

“We hope these new peanut varieties will offer producers a profitable dryland or limited irrigation crop option,” Lamb said. “What makes this project truly exciting is that it takes the entire agricultural value chain into account, using cutting-edge research to create an abundant, affordable and high-quality product that works to protect natural resources, improve health and support economies in Texas and beyond. We appreciate the support of this work by Chevron.”

Chevron is building the capacity to produce 100,000 barrels a day of renewable fuels in its manufacturing system by 2030. Securing a reliable source of lower lifecycle carbon intensity renewable feedstocks is a priority for the company.

“Chevron is thrilled to team with Texas A&M AgriLife to work to develop the next generation of renewable fuel feedstocks,” said Michelle Young, renewables program manager for Chevron Downstream Technology and Services. “This collaboration has the potential to deliver high-quality oil to produce renewable fuels while providing peanut farmers in the U.S. with another way to maximize the value of their operations.”

“The Texas Peanut Producers Board is excited to support the ‘diesel nut’ project and views it as one more tool for farmers in Texas,” said Shelly Nutt, Texas Peanut Producers Board executive director.

“Peanut farmers have long realized the value of using peanuts not only as a cash crop, but also as a crop that adds nutrients to the soil, creating a sustainable production system,” Nutt said. “With the success of this project, farmers could add a low-input, high-yielding ‘diesel nut’ with the ability to grow on marginal land or with limited water availability, into their rotation program and would not be competing with the high-quality, edible peanut market the board has worked so hard to achieve.”

Increasing oil content in ‘diesel nut’ peanut varieties

Currently, food-grade peanut varieties have an oil content of approximately 48%. However, several high-oil breeding lines have around 55-60% oil content. With those yields, “diesel nut” peanuts could yield as much as 350 gallons of oil per acre, compared to soybeans’ current oil yields of approximately 25 to 50 gallons per acre.

AgriLife Research peanut breeders, including Michael Baring, Bryan-College Station; Charles Simpson, Ph.D., Stephenville; and Mark Burow, Ph.D., Lubbock, began working on high-oil breeding lines 15 years ago. Cason said four of those most promising lines were selected to begin studying the agronomics and yields.

“We also are developing new crosses and screening Texas A&M AgriLife germplasm, including the wild germplasm collection maintained by Simpson,” Cason said. “Our breeders are searching for germplasm with even higher oil content to develop the most elite cultivars that will also perform in dryland conditions and produce the highest oil content.”

Producing ‘diesel nut’ varieties in non-irrigated areas

Cason and team see possibilities to bring peanut production back to non-irrigated, rain-fed areas utilizing this high-oil germplasm. They will breed into these lines the qualities of improved disease and drought tolerance as well as continuing to increase oil content.

He said major advances in disease resistance have already been made in food-grade peanut varieties, such as resistance to nematodes from wild species, Sclerotinia blight and tomato spotted wilt virus. These traits can now be incorporated into the “diesel nut” lines to create a robust renewable fuel feedstock.

“With our edible breeding lines, we’ve also been looking at drought tolerance, but not on any of the lines producing higher oil,” Cason said. “Now we’ve pulled everything out and started planting in Vernon and Stephenville and will grow some under dryland and irrigation. We are treating this year as kind of a pilot year.”

West Texas begins the peanut-planting season in late April and early May, while in South Texas, peanuts are planted as late as June 25. Harvest begins in October and is done by Thanksgiving.

A peanut crop usually needs 27 inches of moisture from irrigation and rain. This typically produces about 5,000 pounds per acre of high-quality peanuts. In contrast, the drought-tolerant research at Lubbock studying peanut production with only 7-12 inches of rain produced about 2,800 pounds of edible peanuts per acre in 2020.

“One thing that will help the ‘diesel nut’ succeed is that when you don’t irrigate a peanut, you run the risk of aflatoxin, which can be devastating to food-grade peanuts,” Cason said. “But that won’t matter when the crop is being crushed for biofuel, so regardless of how much moisture, if the grower can grow something, they can market it.”

The goal now is to adapt “diesel nut” lines to new growing regions across Texas and the U.S. where the crop can perform under limited irrigation and dryland production. This, coupled with the development of best management practices for crop production systems and the logistics of harvest, transport and storage will be necessary to rapidly advance the production of renewable diesel feedstocks.

Other ‘diesel nut’ project components

A large contingent of Texas A&M AgriLife personnel will be working on the project, including agronomists, breeders, plant microbiologists, crop physiologists, biochemists, soil scientists, economists and crop modelers in College Station and at multiple Texas A&M AgriLife Research and Extension Centers in key peanut production areas of the Rolling Plains, South Plains and South Texas.

While Cason and the breeding team are developing breeding lines, Ribera will lead the development of risk-based, comprehensive enterprise budgets focused on the peanuts’ oil yield, reliability and viability as a renewable diesel feedstock.

With that objective, Ribera’s team will include modelers who will assess transportation, shelling and crushing infrastructure as well as regulatory constraints to come up with the baseline carbon intensity.

“When considering a renewable fuel source, every energy input into the production and processing of the peanuts until the fuel reaches the pumps will be important to determining the carbon intensity,” said Baltensperger. “We look at energy in for energy out and which is most carbon considerate. We want the carbon intensity baseline to be as low as possible if we are to optimize peanuts where it still makes sense to produce oil for fuel.”

McCutchen said this project could bring peanut production back to areas that previously grew the crop but ran out of water. The agronomic side of the project will concentrate on peanut lines that can be grown on marginal lands and still give high per-acre vegetable oil yields.

• The team of cropping system specialists will also develop cropping systems that optimize growth, harvest and yield for “diesel nuts.” They will evaluate conservation tillage, as research in peanut-producing regions of Texas has shown that soil organic carbon increased by combining conservation tillage with cover crops.
• Rotational systems, cover crops, tillage and fertilizer practices will be evaluated under dryland and limited irrigation to create a cropping system with the lowest possible carbon footprint. High-throughput greenhouse assays will be used to find novel endophytes, which will be important for promoting drought tolerance and overall plant health.

• When enough information is available and advances are made, Emi Kimura, Ph.D., AgriLife Extension state peanut specialist, Vernon, will lead the outreach to inform producers about the research outcomes.

“The end goal of this project is the commercialization of elite high-oil varieties that producers can plant and oil that Chevron can use,” said Carl Muntean, director of Texas A&M AgriLife Corporate Engagement and Research Support.