The DOI matches its Crossref record; 25 of the 27 references it cites were found in a registry or an index.
Environmental, economic, and energetic costs and benefits of biodiesel and ethanol biofuels
Open accessAbstract
Negative environmental consequences of fossil fuels and concerns about petroleum supplies have spurred the search for renewable transportation biofuels. To be a viable alternative, a biofuel should provide a net energy gain, have environmental benefits, be economically competitive, and be producible in large quantities without reducing food supplies. We use these criteria to evaluate, through life-cycle accounting, ethanol from corn grain and biodiesel from soybeans. Ethanol yields 25% more energy than the energy invested in its production, whereas biodiesel yields 93% more. Compared with ethanol, biodiesel releases just 1.0%, 8.3%, and 13% of the agricultural nitrogen, phosphorus, and pesticide pollutants, respectively, per net energy gain. Relative to the fossil fuels they displace, greenhouse gas emissions are reduced 12% by the production and combustion of ethanol and 41% by biodiesel. Biodiesel also releases less air pollutants per net energy gain than ethanol. These advantages of biodiesel over ethanol come from lower agricultural inputs and more efficient conversion of feedstocks to fuel. Neither biofuel can replace much petroleum without impacting food supplies. Even dedicating all U.S. corn and soybean production to biofuels would meet only 12% of gasoline demand and 6% of diesel demand. Until recent increases in petroleum prices, high production costs made biofuels unprofitable without subsidies. Biodiesel provides sufficient environmental advantages to merit subsidy. Transportation biofuels such as synfuel hydrocarbons or cellulosic ethanol, if produced from low-input biomass grown on agriculturally marginal land or from waste biomass, could provide much greater supplies and environmental benefits than food-based biofuels.
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In the citing paper
“Industrialized nations with biofuels targets, such as the United States and members of the European Union, are unlikely to have the land base needed to meet their growing demand for current-generation agricultural biofuels, which are largely produced from food and feed crops (e.g., maize, oil palm, rapeseed, soy)”
From Carbon payback times for crop-based biofuel expansion in the tropics: the effects of changing yield and technology (2008) · cites this paper as Hill et al 2006
Experimental — accuracy not yet measuredThe source backs part of the claim, not all of it — or backs it for a different population, condition or comparison.
In the citing paper
“However, including generalized estimates of upstream emissions to grow, produce and transport would decrease biofuel carbon offsets used here by ∼ 80% for cornethanol, ∼ 20% for cane-ethanol and ∼ 60% for soy-biodiesel (Hill et al 2006), thereby increasing the carbon payback time.”
From Carbon payback times for crop-based biofuel expansion in the tropics: the effects of changing yield and technology (2008) · cites this paper as Hill et al 2006
Experimental — accuracy not yet measuredThe cited source says what the claim attributes to it.
In the citing paper
“The concept of energy balance, or Net Energy Balance (NEB), evaluates the amount of energy from the biofuel to the fossil energy input necessary for feedstock cultivation and conversion; for instance, soybean biodiesel yields approximately 93% more energy than is invested in its production [103].”
From Biofuels, E-Fuels, and Waste-Derived Fuels: Advances, Challenges, and Future Directions (2025) · cites this paper as [103]
In the citing paper
“Currently, bioethanol is produced by fermentation of agricultural crops, mainly sugarcane in Brazil (Goldemberg 2007) and/or corn in the US (Hill et al. 2006).”
From Renewable energy from Cyanobacteria: energy production optimization by metabolic pathway engineering (2011) · cites this paper as Hill et al. 2006
In the citing paper
“biodiesel yields 93% more [99]”
From The potential of biofuels from first to fourth generation (2023) · cites this paper as [99]
In the citing paper
“ethanol yields 25% more energy than that invested in its production”
From The potential of biofuels from first to fourth generation (2023) · cites this paper as [99]
In the citing paper
“Advanced fuels share many advantages over first-generation biofuels, such as reduced land requirements and minimal fertilizer, pesticide, and fossil energy input [66].”
From Investigation of Biofuel as a Potential Renewable Energy Source (2021) · cites this paper as [66]
In the citing paper
“the indirect effects of bioenergy production on CO 2 emissions are also important concerns”
From Bioenergy production and environmental impacts (2018) · cites this paper as Hill et al. 2006
In the citing paper
“Review on environmental impacts suggested that substituting fossil fuels with biofuels could significantly reduce greenhouse gas emissions and air pollution (e.g., particulate matter).”
From Biomass and biofuels in China: Toward bioenergy resource potentials and their impacts on the environment (2018) · cites this paper as [6]
In the citing paper
“Overall, biofuels from cellulosic feedstocks (e.g., corn residues, switchgrass) and certain non-grain conventional crops (e.g., cassava, Jatropha) have much less greenhouse gas (GHG) emissions and air pollutants than fossil fuels (e.g., gasoline, diesel) on an energy basis [6][7][8].”
From Biomass and biofuels in China: Toward bioenergy resource potentials and their impacts on the environment (2018) · cites this paper as [6]
In the citing paper
“Most studies agreed that, without land use change impacts, biofuels release much less GHG emissions than their fossil fuel counterparts on a per unit energy basis [6,7,44].”
From Biomass and biofuels in China: Toward bioenergy resource potentials and their impacts on the environment (2018) · cites this paper as [6]
In the citing paper
“Overall air quality can be improved if using biofuels in place of fossil fuels, however specific emission reduction still varies among different biofuel feedstocks, air quality species and biofuel pathways [6,77] (Table 2).”
From Biomass and biofuels in China: Toward bioenergy resource potentials and their impacts on the environment (2018) · cites this paper as [6]
In the citing paper
“For example, biofuels can help reduce PM 2.5 and SO 2 but not nitrous oxide (N 2 O), a potent GHG emissions (Table 2).”
From Biomass and biofuels in China: Toward bioenergy resource potentials and their impacts on the environment (2018) · cites this paper as [6]
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Second Generation Biofuels: High-Efficiency Microalgae for Biodiesel Production
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Self-citation
Metadata
- Authors
- Hill, J., Nelson, E., Tilman, D., Polasky, S., & Tiffany, D.
- Affiliations
- University of Minnesota (US)
- Corresponding author
- Tilman, David
- Venue
- Proceedings of the National Academy of Sciences
- Publisher
- National Academy of Sciences
- Published
- 2006-07-25
- Volume
- 103
- Issue
- 30
- Pages
- 11206-11210
- ISSN
- 0027-8424 (ISSN-L)
- 1091-6490
- PMC
- PMC1544066
- OpenAlex
- W2164449327
- Cited by
- 2,871
- References
- 27
- Citations by year
- 2026: 36 · 2025: 57 · 2024: 60 · 2023: 86 · 2022: 89 · 2021: 138 · 2020: 103 · 2019: 126 · 2018: 147 · 2017: 155 · 2016: 149 · 2015: 171 · 2014: 175 · 2013: 242 · 2012: 228
- FWCI
- 117.55
- Type
- journal article
- Language
- en
- Open access
- green
- europepmc.org
- Locations
- Proceedings of the National Academy of Sciences (publishedVersion)
- Europe PMC (PubMed Central) (publishedVersion)
- PubMed Central (publishedVersion)
- PubMed (publishedVersion)
- Bowdoin - Digital Commons (Bowdoin College) (submittedVersion)
- Funders
- National Science Foundation (0080382)
- Howard Hughes Medical Institute
- Bush Foundation
- Topics
- Physical Sciences › Engineering › Biomedical Engineering › Biofuel production and bioconversion
- Physical Sciences › Environmental Science › Environmental Engineering › Environmental Impact and Sustainability
- Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Bioenergy crop production and management
- Keywords
- biodiesel, ethanol, corn ethanol, soybean biodiesel, net energy analysis, life cycle assessment, greenhouse gas emissions, air pollutants, pesticide use, biofuel subsidies, oil displacement, biofuel economics, cellulosic ethanol, biomass waste
- MeSH terms
- Agriculture, Air Pollutants, Air Pollution, Ethanol, Vehicle Emissions, Energy-Generating Resources, Environment, Fossil Fuels, Gasoline, Humans, Petroleum, Glycine max, Biomass
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