Research Archives - Growth Energy

Considering Historical Land Use When Estimating Soil Carbon Stock Changes of Transitional Croplands

Holly Cullen — Mon, 15 Jan 2024 14:24:05 +0000

By Kenneth Copenhaver and Steffen Mueller

Abstract: Understanding changes to soil organic carbon storage (SOC) requires knowledge of detailed land use history. Many satellite-based analyses of land use change have been conducted over short periods (typically 5 to 10 years) to investigate causality to a demand increase in an agricultural commodity. However, statistically significant changes in SOC are not readily observable during this time and typically require decades for meaningful differences to accrue. This study aimed to determine land use and soil organic carbon stocks on land parcels over 36 years (1985–2021) located in areas where historical land use transitions between cropland and non-cropland are prevalent. Aerial and satellite imagery were analyzed across 25,992 hectares in ten counties across the Corn Belt. Grower interviews were conducted to solicit feedback on the drivers of land use change. Finally, SOC analyses associated with land use changes were determined using two process-based models. Analysis showed that 371 of the parcels had remained in cropland, 611 parcels transitioned into non-cropland, and 18 parcels were identified as non-cropland. The grower surveys indicated that the most common reasons for returning land to crop was the difficulty getting land re-enrolled in the CRP and reduced cattle prices. Both the SALUS and GREET-CCLUB models were parameterized to assess soil carbon changes for the respective land use history, and both models returned consistent SOC increases at the county level over time.

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Impact for the U.S. Economy from Implementation of §45Z of the Inflation Reduction Act (IRA)

Houston Ruck — Wed, 16 Aug 2023 16:49:17 +0000

Section 45Z of the Inflation Reduction Act (IRA) provides a tax credit for the domestic production of clean transportation fuels including ethanol, biodiesel, and sustainable aviation fuels. Also known as the Clean Fuel Production Credit, the tax credit applies to fuels produced after December 31, 2024, and sold before Dec. 31, 2027. The base amount of the credit for nonaviation fuels is $0.20 a gallon multiplied by an emissions factor. This base credit can be increased to $1.00 per gallon (a multiple of five) for transportation fuel produced in facilities that meet prevailing wage and apprenticeship requirements outlined in the IRA.

The Section 45Z tax credit will provide significant financial incentive for ethanol producers to make necessary capital expenditures to capture and process CO2 and for farmers to increase production of low carbon intensive corn for ethanol production. These incentives are expected to more than double the current number of ethanol plants capturing CO2 (from 50 to 124) and capture of CO2 (from 9.5 million tons to 23.8 million tons) over the three-year period of the tax credit.

Qualification for the tax credits provided by §45Z is determined by reductions in the carbon intensity (CI) of ethanol. The main ways the CI of ethanol can be reduced are through increasing the recovery of CO2 by ethanol producers, use of renewable natural gas (RNG), and utilization of corn produced using practices that reduce its CI and, in turn, ethanol produced from low CI corn. Currently a relatively small percent of ethanol plants capture and market CO2.

A combination of operational changes by ethanol producers and increased use of low CI corn feedstock is expected to result in at least a 50 percent reduction in the carbon intensiveness of ethanol leading to a $0.55 per gallon tax credit. Since low CI corn plays a substantial role in this reduction, ethanol producers are expected to share $0.10 per gallon (3.3 cents per bushel) of the credit with farmers supplying low CI corn and pay a 10.3 percent premium for qualifying feedstock.

The ethanol industry is expected to increase capital expenditures by $2.3 billion. Corn growers are expected to spend $6.8 billion to produce 2.4 billion bushels of corn needed to produce the increased CO2 volume and will realize an additional $1.9 billion in revenue. As shown in Table ES1 these impacts are expected to provide $21.2 billion in GDP for the U.S. economy, nearly $13.4 billion in household income, and support more than 192,000 jobs in all sectors of the national economy.

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Decarbonizing Combustion Vehicles: Transportation Energy Institute

Holly Cullen — Sat, 01 Jul 2023 13:40:36 +0000

S&P Global Mobility1 reports that in July 2021 BEVs represented only 0.42% of vehicles in operation, which left 282 million internal combustion engine vehicles (ICEVs) on the roads in the U.S. By 2030, it is projected there will be 290 million ICEVs in operation. That same year, BEV sales were projected to total nearly 2.8 million units. If LDV sales maintain their historical level of about 16.5 million vehicles per year, this would mean that, even in 2030, consumers will purchase nearly 14 million new ICEVs, and those vehicles can be expected to be on the road in the U.S. for at least fifteen years. Accordingly, large numbers of ICEVs consuming liquid fuels will be on the road in the U.S. for decades to come.

Given the objective to reduce carbon emissions from the transportation sector, waiting for the market to transition to ZEVs without seeking solutions for the dominant powertrain on the roads is a strategy which ignores the substantial reductions which can be achieved in current and future ICEVs. Embracing strategies to reduce carbon emissions from the nearly 300 million ICEVs that will continue to operate in the U.S. for the next several decades is imperative.

Fortunately, total lifecycle, as well as tailpipe, emissions reductions are already being achieved by increasing use of biofuels and reducing the carbon intensity of the fuel mixtures used in ICEVs. Additional near-term steps to reduce the carbon intensity of fuels will play a critical role in limiting the expected increase in cumulative mobile source greenhouse gas (GHG) emissions. ICEV technologies and the associated fuels can continue to be employed over broad and energy-intensive transportation applications while making substantial contributions to near- and long-term GHG emissions reductions. In fact, substantial reductions in GHG emissions from LDVs in the near term can only be achieved by reducing emissions from ICEVs.

Stillwater Associates was engaged by the Transportation Energy Institute to identify and analyze the potential opportunities to expand on this critical GHG-reduction strategy. In this report, we examine the benefits achievable through the decarbonization of the existing on-road U.S. ICEV fleet given the extended timeframe which will be required to transition that fleet to ZEVs.

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EH&E Response to Proposed Renewable Fuel Standard (RFS) Program Standards for 2023–2025

Holly Cullen — Fri, 10 Feb 2023 15:05:46 +0000

We at Environmental Health & Engineering (EH&E) are a multi-disciplinary team of environmental health scientists and engineers with expertise in measurements, models, data science, lifecycle analyses (LCA), and public health. Members of our team conducted a state of the science review of the carbon intensity (CI) for corn ethanol in the United States (U.S.), as well as a reply supporting our work and a comprehensive assessment of the impacts of corn ethanol fuel blends on tailpipe emissions. A primary conclusion from our past and present work is that the best available science suggests a well-to-wheel corn starch ethanol CI of 51 gCO2e/MJ, representing an approximately 46% reduction in GHG emissions relative to the petroleum gasoline baseline. Over the past several months, we have submitted public comments to governmental agencies including EPA and the State of Washington. We have also recently published a reply that shares feedback on a recent but questionable study of domestic land use change. A theme present across all of our analyses is that, overall, the CI estimates for the indirect land use change (iLUC) associated with corn starch ethanol have been converging on
lower values when considering the best available science and improved models. The latest analyses of the four commonly relied upon models—GTAP-BIO, FAPRI-CARD, MIRAGE, and GLOBIOM—show results that are 2-fold to 4-fold lower than the results from studies that use outdated models. Studies that do not incorporate the best available science suggest a strong link between biofuel expansion and iLUC; as we will discuss, recent empirical research does not support that relationship.

We submit this letter to EPA in response to the proposed Renewable Fuel Standard (RFS) Program: Standards for 2023–2025 and Other Changes (hereafter, “the Set Proposal”) and the associated Draft Regulatory Impact Analysis (DRIA).

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Assessment of Production and Consumption Capacity of Conventional Ethanol in 2023-2025

Holly Cullen — Thu, 09 Feb 2023 15:14:38 +0000

EIA lists the U.S. ethanol nameplate production capacity at 17.38 billion gallons per year as of January 1, 2022. How much of this ethanol production capacity can be used is primarily a function of the available feedstock, corn, and the conversion capacity of ethanol plants. We consider three different approaches to determine the real-world maximum potential ethanol production in 2023: historical maximum, previous year, and potential expansion.

The highest year of ethanol production was 2018, when 16.091 billion gallons of ethanol were produced domestically. In 2021, it is estimated that 15.016 billion gallons of ethanol were produced. We believe that both these figures represent conservative estimates of how much ethanol could reasonably be produced in 2023. The 2021 volume was suppressed substantially by low demand for transportation fuel in response to the COVID-19 pandemic. And neither figure accounts for the continuing growth in the productivity of U.S. corn growers or the steady improvements in the efficiency of U.S. corn ethanol plants. As explained below in greater detail, these developments have allowed U.S. ethanol production to continuously increase their production capability without requiring increasing corn acreage or adversely impacting the supply of corn available for other domestic non-ethanol demands or export markets. In fact,
we conclude that, accounting for these developments, 16.147 billion gallons could be produced domestically in 2023.

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Review of EPA’s Proposed RFS Standards for 2023-2025

Holly Cullen — Wed, 01 Feb 2023 16:40:55 +0000

Ramboll and Net Gain Ecological Services have reviewed the Environmental Protection Agency’s (EPA’s) Proposed Renewable Fuel Standard 2023-2025 rule (the “Set Proposal” or “Proposed Rule”) and the accompanying Draft Regulatory Impact Analysis (DRIA) along with many of the cited articles. After careful review of the Set Proposal and the DRIA, and based on our own literature review and independent analysis, we find that there is no demonstrated causal link between the Renewable Fuel Standard (RFS), and land use change (LUC) or water quality. Furthermore, we conclude that the renewable fuel volumes suggested in the Proposed Rule for 2023-2025 are likely to have minimal or no effects on water quantity, quality or LUC. Our analysis focused on:

• The economic effect of the RFS on corn prices and acres planted in corn.
• The causal linkage between the RFS and LUC.
• Wetlands, ecosystems, habitat, and wildlife.
• Soil and water quality and water quantity.

Overall, our research concludes that the studies conducted by the EPA (2022b), Taheripour et al. (2022a), and Austin et al. (2022), are more representative of the likely effects of the implied conventional volume and ethanol production on corn prices and corn acres planted than are the results of Lark et al. (2022). The methods used by the EPA (2022b) and Taheripour et al. (2022a) account for effects of the global and domestic economies. The methods we use in this report, although high level, are based on 18 years of observed data. The results of our analysis confirm that the implied conventional volume has minimal to no effect on corn prices and acres of corn planted, consistent with the work by the EPA (2022b) and Taheripour et al. (2022a).

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GHG Analysis of Dry Mill for Corn Ethanol Production under IRA

Holly Cullen — Fri, 02 Dec 2022 15:30:15 +0000

The Inflation Reduction Act (IRA) requires the calculation of greenhouse gas (GHG) emissions based on the GREET model for credit generation under Section 45Z. As specified in the Act: “The lifecycle greenhouse gas emissions of such fuel shall be based on the most recent determinations under the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model developed by Argonne National Laboratory, …”

Meeting the requirements of the Act is possible by grouping the GHG reductions options from dry mill ethanol plants into categories that are readily verified. This document reviews the GHG analysis for corn ethanol in GREET and identifies leading options to reduce GHG emissions and their corresponding effect on life cycle GHG emissions.

• Typical Dry Mill Ethanol Plant
• Carbon Capture and Sequestration
• Renewable Power
• Renewable Natural Gas
• Low Carbon Ammonia
• Manure Application
• Fertilizer Usage, including Bio-based Fertilizer
• No Till Farming
• Cover Crop

Each of these emission reduction options is represented in the GREET model and fuel producers could identify a combination of ethanol plant operation and corn farming parameters that are consistent with the GHG emission thresholds of the IRA to calculate their life cycle GHG emissions. Readily available GREET results for corn ethanol plant operation could be used by fuel producers to demonstrate GHG reductions under Section 45Z.

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Impact on Consumer Savings from Year-Round Nationwide E15 Use

Holly Cullen — Thu, 13 Oct 2022 13:58:50 +0000

One of the most significant opportunities for both consumers and the ethanol industry lies in expanding demand by increasing use of higher blend levels. Since motor gasoline containing higher levels of ethanol typically sell at a discount to regular gasoline, consumers benefit from lower prices while farmers and others in the economy benefit from increased production of ethanol. Most motor gasoline used in the U.S. contains 10 percent ethanol (E10). However, demand for higher blends such as E15 (15 percent ethanol) also are increasing. While nationwide sales of E15 are not reported, according to the U.S. Environmental Protection Agency (EPA), E15 is sold in 31 states and the number of retail stations offering E15 has more than doubled over the last five years, from 1,200 in 2017 to an estimated 2,700 currently. In April 2022, the Biden Administration announced that E15 would be available for sale nationwide during the summer months. In response, EPA issued an emergency fuel waiver to allow E15 to be sold in the 2022 summer driving months (June through September). Prior to the announcement, EPA allowed the year-round sale of E15 nationwide but restricted E15 sales during summertime months in states without a Reformulated Gasoline (RFG) Program. This restricted E15 sales in roughly two-thirds of the country in the peak summer driving months. EPA’s emergency waivers following the President’s April announcement removed this ban and allowed drivers across the U.S. to benefit from E15 for the 2022 summer driving season.

This study estimates the impact for consumers and the U.S. economy of expanding E15 use to the nation’s entire motor gasoline supply based on annualized current (year-to-date 2022) production and consumption levels and input prices. As such, this study updates and revises our 2021 analysis of the impacts of nationwide E15 use that was based on historical data.

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Comparison of Exhaust Emissions Between E10 and Splash Blended E15

Holly Cullen — Sat, 25 Jun 2022 14:34:13 +0000

For this program, two fuels, namely an E10 and E15, were tested on twenty 2016 and newer modern gasoline fueled vehicles over triplicate Federal Test Procedure (FTP) cycles. The E10 fuel was a California Reformulated Gasoline. The summer-grade E10 fuel was sourced from four (4) different refineries that were selected by CARB. The E10 fuels were blended together in four equal parts to create the final E10 fuel. The E15 fuel was created by splash blending denatured ASTM D4806 fuel grade ethanol with the final E10 fuel. Testing was performed on twenty light-duty gasoline vehicles that included a mixture of technologies, such as gasoline direct injection (GDI), port fuel injection (PFI) as well as PFI+GDI fuel systems that are representative of the current California gasoline fleet. One hybrid electric vehicle (HEV) equipped with a PFI engine was also used. The vehicle test matrix had provisions for five vehicles on each emissions standards category (i.e., SULEV30, ULEV50, ULEV70, and ULEV125).

The primary objective of this program is to better understand the impact of increasing ethanol blending on gaseous and particulate emissions from current gasoline direct injection (GDI) and port fuel injection (PFI) light-duty vehicles in California. For this project, two fuels, namely an E10 and E15, were tested on twenty 2016 and newer modern gasoline fueled vehicles over triplicate FTP cycles. Measurements included regulated emissions, fuel economy, PM mass, particle number, black carbon, and emissions of benzene, toluene, ethylbenzene, xylene isomers, 1,3-butadiene, ethanol, and carbonyl compounds.

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Taheripour et al. Response to Lark et. al. RFS Study

Holly Cullen — Sun, 01 May 2022 15:12:32 +0000

We recently reviewed the article published by Lark et al. (2022) in PNAS, detected various problematic assumptions, approaches, data, and results in that study. Based on our findings, we concluded that these authors overestimated GHG emissions of corn ethanol consumption due to the RFS. In response to our comments, Lark et al. have stated that they believe “Taheripour et al.’s conclusions to be unsupported and based upon several misunderstandings and misinterpretations of [our] methods and results.” In what follows, we review the responses provided by Lark et al. and show that our comments did not misinterpret Lark et al.’s findings, rather that our comments are supported by the literature and actual observation and are based on the statements provided by Lark et al. in their original publication.
In this document, we provide responses to the Lark et al. comments one by one. To avoid confusion, throughout we refer to Lark et al.’s 2022 original publication as Lark et al.(a) and the response of those authors to our original comments as Lark et al.(b).
Our detailed review of the original paper and the responses by those authors reveals various major deficiencies, problematic assessments, and misinterpretation of the existing literature in Lark et al.(a)&(b). In summary, our major findings are:

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