Biofuels
Exploring Our Content
Fast Facts
View our summary of key facts and information.
Before You Watch Our Lecture
Maximize your learning experience by reviewing these carefully curated videos and readings we assign to our students.
Our Lecture
Watch the Stanford course lecture.
Additional Resources
Find out where to explore beyond our site.
Fast Facts About
Biofuels
Principal Energy Use: Transportation
Form of Energy: Chemical
Biofuels are an energy currency derived from renewable biological sources, such as plants, algae, and organic waste materials. They can replace fossil fuels like gasoline and diesel.
Biofuels are considered a part of the broader strategy to reduce greenhouse gas emissions and dependence on finite fossil fuel resources. However, current feedstock use and production methods raise debates and concerns related to their environmental impact, land use, and competition with food production that are yet to be solved with more sustainable biofuel production.
First-generation biofuels are biofuels produced from feedstocks that are primarily food crops or crops specifically grown for fuel production. The main types of first-generation biofuels include:
- Bioethanol: Typically produced from crops like corn (maize), sugarcane, and wheat. It is the most widely used biofuel and is often blended with gasoline to reduce its carbon emissions. It can only be blended with gasoline up to 10% (E10) without requiring a special vehicle (flex-fuel).
- Biodiesel: Primarily produced from vegetable oils (such as soybean, rapeseed, and palm oil) and animal fats. It can be blended with traditional diesel up to 20% (B20) in regular diesel engines.
First-generation biofuels have important drawbacks, including competition with food crops and land use change. Additionally, the energy balance and environmental benefits of first-generation biofuels can vary depending on factors such as crop type, land-use change, production methods, and transportation. In some cases, they can have a larger carbon footprint than their fossil fuel counterparts.
Because of these concerns, there has been an effort to shift toward second-generation and advanced biofuels that use non-food feedstocks, such as agricultural residues, algae, and other non-food plant materials. These newer biofuels are more energy intensive and technologically challenging to produce, limiting their growth. Second-generation biofuels include renewable diesel and sustainable aviation fuel (SAF), drop-in fuels made mainly from processing animal fats and used cooking oil. Cellulosic ethanol can be produced from agricultural residues, energy crops, and forestry residues.
Biofuels are mainly used for transportation, but they are a very small contributor to transportation energy. Demand for biofuels is expected to grow in the next five years due to climate goals and policy mandates. Visit our Gasoline, Diesel, Jet Fuel, etc. page for more information about transportation fuels.
Significance
Energy Mix
1% of world 🌎
2% of US 🇺🇸
98% of Biofuel Use Is for Transportation
4%
of global transportation energy comes from biofuels
Ethanol
World
Largest Producers
US 55% 🇺🇸
Brazil 27% 🇧🇷
of global ethanol production
Largest Consumers
US 47% 🇺🇸
Brazil 28% 🇧🇷
of global ethanol consumption
Corn vs Sugarcane for Ethanol Production
In the US, ethanol production is mostly from corn. In Brazil, it is mostly from sugarcane. Corn produces only 400 gallons of ethanol per acre per year, whereas sugarcane produces 1,400 gallons of ethanol per acre per year. The two crops have very different carbon footprints and land, water, and fertilizer usage.
Largest Consumers
Texas 11%
California 10%
of ethanol consumed in the US
Biodiesel
World
Largest Producers
Europe 29%
US 24% 🇺🇸
of global biodiesel production
Largest Consumers
US 20% 🇺🇸
Indonesia 18% 🇮🇩
of global biodiesel consumption
Largest Consumers
California 17%
Texas 12%
of biodiesel consumed in the US
Renewable Diesel
Largest Producers
Europe 44%
US 32%
of global renewable diesel production
*Remaining production is primarily in Asia, but is shipped to Europe.
Largest Consumer
California 99%
of total renewable diesel consumed in the US
Spotlight on Sustainable Aviation and Shipping Fuels
Aviation greenhouse gas (GHG) emissions represent 2% of global emissions (4% of emissions in the US). Airlines have committed to carbon-neutral growth in international commercial aviation beginning in 2021 and US airlines have set a goal to reduce carbon dioxide (CO2) emissions by 50% by 2050. Sustainable Aviation Fuels (SAF) are considered a solution for decoupling carbon growth from market growth of the aviation industry.
SAF is a drop-in fuel that can use the same supply infrastructure as jet fuel. It can be produced from a number of sources including forest residues, waste oil and fats, green and municipal waste, and non-food crops. Depending on the feedstock and technologies used to produce it, SAF can reduce greenhouse gas (GHG) emissions up to 80% compared with regular jet fuel. Currently, most SAF supply comes from processing animal fats and used cooking oil in a process called HEFA (hydroprocessed esters and fatty acids). This process is energy-intensive and requires hydrogen, which today is primarily made from natural gas. Some companies are producing SAF using carbon dioxide captured from places like pulp and paper mills and ethanol refineries (CO2-to-fuel), but still at a very small scale.
Challenges for providing SAF include: 1) Supply. Current SAF production is less than 1% of the global jet fuel demand. It is expected to increase from 106 billion gallons in 2019 to 230 billion gallons in 2050. This would entail several hundred million tons of biomass per year and significant increases in solar and wind energy to produce green hydrogen. 2) SAF prices. The price of SAF today is not cost competitive yet. Research and development (R&D) can help bring the cost down.
Similarly to SAF, Sustainable Marine Fuels (SMFs) are produced by converting feedstocks like wastes and non-food energy crops into energy-dense fuels that can be safely used in marine engines and can lower GHG emissions relative to the heavy fuel oil (HFO) used by many cargo ships.
Other options to reduce emissions in aviation and shipping are hydrogen, ammonia, and electrification. However, airplanes that can run on hydrogen or ammonia are at the design stage and will not be available commercially until 2035. Electrification can be useful for small distance flights.
Drivers
- Global and national policies, such as tax incentives and renewable fuel standards, encourage the production of biofuels as part of their GHG reduction strategies
- Semi-renewable source of energy if resources are managed sustainably
- Energy diversification by reducing reliance on oil and helping mitigate energy price volatility
- Energy security by incentivizing domestic production and reducing reliance on foreign oil
- Rural development; production of biofuels can support economic opportunities in rural areas
- Technological advances that have improved the efficiency and cost-effectiveness of biofuel production
Climate Impact:
Low to Medium
- Possibly carbon neutral, but bioenergy crops have different energy yields, and some crops require significant energy inputs, reducing their carbon savings
- Land use change such as deforestation or conversion of peat swamps to fuel crops releases carbon dioxide and methane
Environmental Impact:
Medium to High
- Does not improve air pollution: vehicles burning biofuels still emit harmful air pollutants
- Bioenergy crop production may induce deforestation; in Southeast Asia, rainforests were converted to palm oil plantations to feed the EU’s demand for biodiesel
- Agricultural processes can impact soil, water resources, and local biodiversity
Before You Watch Our Lecture on
Biofuels
We assign videos and readings to our Stanford students as pre-work for each lecture to help contextualize the lecture content. We strongly encourage you to review the readings below before watching our lecture on Biofuels.
- How Sustainable Are Advanced and Waste Biofuels?. Transport & Environment. July 1, 2024. (3 pages)
T&E's position on the sustainability of a variety of advanced and waste biofuels. - The Smelly, Greasy Truth About How Sustainable Aviation Fuel Is Made. Canary Media. January 12, 2023. (3 pages)
A truck driver dumpster-dives for used cooking oil in an effort to reduce emissions from commercial aviation. - Biden Team Sets out Path For Ethanol Aviation Fuel Subsidies. Reuters. April 30, 2024. (1 page)
Briefly describes key aspects of Biden's sustainable aviation fuel (SAF) subsidy program. - Biofuels Are Accelerating the Food Crisis — And the Climate Crisis, Too. Canary Media. April 19, 2022. (4 pages)
An opinion piece that provides supporting evidence that land is better used to grow food than to grow fuel. - Stop Trying to Make Algae Biofuels Happen. Canary Media. February 1, 2022. (2 pages)
This article makes the argument that using algae to produce biofuels is unlikely to succeed.
Our Lecture on
Biofuels
This is our Stanford University Understand Energy course lecture on biofuels. We strongly encourage you to watch the full lecture to understand the role of biofuels in our energy system and to be able to put this complex topic into context. For a complete learning experience, we also encourage you to review the Essential readings we assign to our students before watching the lecture.
Presented by: Diana Gragg, PhD; Core Lecturer, Civil and Environmental Engineering, Stanford University; Explore Energy Managing Director, Precourt Institute for Energy
Recorded on: May 22, 2023 Duration: 22 minutes
Additional Resources About
Biofuels
Stanford University
- Energy Science and Engineering Department
- Inês Azevedo - Transition to sustainable and low carbon energy systems
- Adam Brandt - Life cycle assessment of petroleum production, unconventional fossil fuel resources
- Mark Jacobson - Developing large-scale clean, renewable energy solutions
Industry Organizations
Fast Facts Sources
Energy Mix: World 2022 (Statistical Review of World Energy 2023, Energy Institute, Primary Energy: Consumption by fuel), U.S. 2022 (Monthly Energy Review, EIA, Table 1.3 and 10.1).
Use of Biofuels: World 2020 (Global Bioenergy Statistics 2022, World Bioenergy Association, Renewable Energy).
Types of Biofuels: World 2021 (Transport Biofuels, IEA).
Biofuels Demand: World 2022 (Statistical Review of World Energy 2023, Energy Institute, Primary Energy: Consumption by fuel).
Transportation Energy by Source: World 2020 (Renewables 2022 Global Status Report, REN21,Bionergy).
Resources Used for Ethanol Production: World 2021 (Is the biofuel industry approaching a feedstock crunch?, IEA, Total biofuel production by feedstock, main case, 2021-2027).
Impacts of ethanol production: US 2017 (Ethanol’s Contribution to the Dead Zone in the Gulf of Mexico, The Sierra Club; Increased ethanol production to worsen Gulf of Mexico ‘dead zone’, University of Wisconsin-Madison).
Share of Ethanol: World 2022 (Statistical Review of World Energy 2023, Energy Institute, Primary Energy: Consumption by fuel).
Ethanol Largest Production: World 2022 (Annual World Fuel Ethanol Production, Renewable Fuels Association).
Ethanol Highest Consumption: World 2022 (Annual World Fuel Ethanol Production, Renewable Energy - Biofuels Consumption), U.S. 2021 (State Energy Consumption Estimates 2021, EIA, Table C2. Energy Consumption Estimates for Selected Energy Sources in Physical Units, 2021).
Ethanol Highest Penetration: World 2019 (IEA Bioenergy Countries’ Report, IEA, Figure 17: evolution of the share of renewable energy in transport), U.S. 2021 (State Energy Consumption Estimates 2021, EIA).
Ethanol Mandate: World 2022 (Renewables 2022 Global Status Report, REN21,Figure 10. National and Sub-National Renewable Biofuel Mandates and Targets).
Ethanol Highest Production Capacity: U.S. 2023 (U.S. Fuel Ethanol Plant Production Capacity, IEA).
Resources Used for Biodiesel Production: World 2021 (Is the biofuel industry approaching a feedstock crunch?, IEA, Total biofuel production by feedstock, main case, 2021-2027).
Biodiesel Production Impacts: Indonesia 2022 (Indonesia makes progress towards zero palm oil deforestation – but gains in forest protection are fragile, SEI), Brazil 2011 (Deforestation and the social impacts of soy for biodiesel: Perspectives of farmers in the South Brazilian Amazon, Ecology and Society 16(4): 4).
Biodiesel Largest Production: World 2022 (Transport biofuels, IEA, Biofuel production by country/region and fuel type, 2016-2022).
Biodiesel Highest Consumption: World 2022 (International Energy Information, EIA, Biofuels), US 2021 (State Energy Consumption Estimates 2021, EIA, Table C2. Energy Consumption Estimates for Selected Energy Sources in Physical Units, 2021).
Biodiesel Highest Penetration: World 2019 (IEA Bioenergy Countries’ Report, IEA, Figure 17: evolution of the share of renewable energy in transport), U.S. 2021 (State Energy Consumption Estimates 2021, EIA).
Biodiesel Mandate: World 2022 (Renewables 2022 Global Status Report, REN21,Figure 10. National and Sub-National Renewable Biofuel Mandates and Targets).
Biodiesel Highest Production Capacity: U.S. 2023 (U.S. Biodiesel Plant Production Capacity, EIA).
Resources Used for Renewable Diesel: World 2022 (Transport Biofuels, IEA).
Renewable Diesel Highest Production Capacity: World 2021 (Transport Biofuels, IEA, Renewable Diesel Production) U.S. 2023 (U.S. Renewable Diesel Fuel and Other Biofuels Plant Production Capacity, EIA).
Renewable Diesel Highest Consumption: World 2021 (Transport Biofuels, IEA, Renewable Diesel Production) U.S. 2021 (State Energy Consumption Estimates 2021, EIA).
Renewable Diesel Highest Penetration: U.S. 2021 (State Energy Consumption Estimates 2021, EIA). Aviation GHG Emissions: World 2022 (Aviation, IEA, Tracking Aviation), US 2021 (Sources of Greenhouse Gas Emissions, EPA, Transportation Sector Emissions).
More details available on request.
Back to Fast Facts