Biofuels matter because they offer a practical way to cut greenhouse gas emissions from transportation, reduce dependence on imported oil, and work with engines and infrastructure that already exist. Unlike wind and solar, which generate electricity, biofuels are liquid energy. That makes them uniquely suited for planes, ships, and heavy trucks that can’t easily run on batteries.
How Much Do Biofuels Cut Emissions?
The core environmental case for biofuels comes down to carbon math. Fossil fuels release carbon that has been locked underground for millions of years, adding new carbon to the atmosphere. Biofuels release carbon that plants absorbed recently, so the net addition is far smaller. How much smaller depends on the feedstock and production method.
Biodiesel and renewable diesel made from soybean, canola, or carinata oils produce 40% to 69% fewer lifecycle greenhouse gas emissions than petroleum diesel, even after accounting for the land-use changes involved in growing those crops. When you remove land-use effects from the calculation, the reduction jumps to 63% to 77%.
Waste-based feedstocks perform even better. Biodiesel made from used cooking oil, animal tallow, or leftover corn oil from ethanol production achieves 79% to 86% lower emissions than petroleum diesel. These waste materials don’t require new farmland or share in the environmental costs of growing crops, which is why their numbers look so much better. The takeaway: not all biofuels are created equal, and the best ones are made from materials that would otherwise be thrown away.
Why Planes and Ships Need Biofuels
Electric cars are gaining ground, but electrification has hard physical limits. A battery powerful enough to fly a commercial jet across the Atlantic would weigh more than the plane itself. Shipping faces similar constraints. These sectors account for a large and growing share of global emissions, and biofuels are one of the few realistic options for decarbonizing them.
The International Energy Agency’s net-zero-by-2050 roadmap calls for biofuels to supply 45% of total aviation energy and 21% of shipping energy by mid-century. Across all oil-based transport fuels, the IEA projects a 41% biofuel blending rate. These aren’t aspirational wishes. They reflect the reality that no other low-carbon technology can do what liquid fuels do in these industries.
Sustainable aviation fuel, or SAF, is already being produced and blended into jet fuel. The U.S. SAF Grand Challenge set a target of 11.4 billion liters of domestic production per year by 2030, with each liter required to cut lifecycle emissions by at least 50% compared to conventional jet fuel. Progress has been slow: in 2024, U.S. SAF production was less than 2% of that goal. Scaling up remains a major challenge, but the technology works and is flying commercially today.
Energy Security and Economic Benefits
Every barrel of biofuel produced domestically is a barrel of crude oil that doesn’t need to be imported. For countries that rely heavily on foreign petroleum, this is a strategic advantage. The U.S. Department of Energy identifies bioenergy as playing an increasingly important role in reducing dependence on foreign energy sources, using feedstocks from domestic farms, forests, and waste streams.
This isn’t just about geopolitics. Domestic biofuel production creates supply chains that employ farmers, truck drivers, refinery workers, and engineers in rural communities. It diversifies the energy mix so that a disruption in one part of the world doesn’t send fuel prices spiking at home. Countries that produce their own transport fuel are less vulnerable to the price shocks and supply squeezes that have historically followed conflicts in oil-producing regions.
Compatibility With Existing Engines
One of the most practical reasons biofuels matter is that they work in today’s vehicles with little or no modification. Most gasoline sold in the United States already contains up to 10% ethanol (E10). The EPA has approved blends of up to 15% ethanol (E15) for all light-duty vehicles from model year 2001 onward. For diesel engines, blends of up to 20% biodiesel (B20) are widely compatible with standard equipment.
Higher blends do require some adjustments. Vehicles designed for E85 (85% ethanol) need flex-fuel engines, and fueling infrastructure storing ethanol blends above 10% or biodiesel blends above 20% must use specially compatible tanks, piping, and seals. But the low-blend versions slip into the existing fuel supply almost invisibly, which is why billions of gallons are already in use every year without most drivers even noticing.
Not All Biofuels Are the Same
Biofuels are typically grouped into generations based on their feedstock. First-generation biofuels come from food crops: corn and sugarcane for ethanol, soybean and palm oil for biodiesel. These are the most commercially mature, but they raise legitimate concerns about competing with food production and driving land-use changes that can offset some of their climate benefits.
Second-generation biofuels use non-food sources like agricultural residues, wood waste, and animal fats. Because these feedstocks are leftovers rather than purpose-grown crops, they sidestep the food-versus-fuel debate. The tradeoff is that breaking down tough plant fibers like lignin and cellulose requires extra processing steps, which adds cost and complexity.
Third-generation biofuels come from microalgae and cyanobacteria, organisms that photosynthesize two to four times faster than land plants. Algae can be grown on non-arable land using saltwater or wastewater, and they naturally produce the oils and alcohols needed for fuel. This generation is still largely in the research and pilot stage, but it represents the highest theoretical yield per acre of any biofuel feedstock.
The Path to Carbon-Negative Fuel
Most low-carbon technologies aim to reduce emissions. Biofuels paired with carbon capture can go further and actually remove carbon from the atmosphere. The concept, known as bioenergy with carbon capture and storage (BECCS), works in three steps: grow biomass that absorbs carbon dioxide as it grows, burn it to generate energy, then capture the carbon released during combustion and store it underground permanently.
Because the plants already pulled that carbon out of the air, capturing it at the smokestack creates a net-negative result. Current capture technologies are reasonably efficient: post-combustion systems capture about 95% of the carbon dioxide produced. The Intergovernmental Panel on Climate Change considers BECCS so important that 87% of its modeled scenarios for limiting warming to 2 degrees Celsius include large-scale BECCS deployment.
BECCS is still early in commercialization, and scaling it will require significant investment in both biomass supply chains and underground storage infrastructure. But it’s one of very few technologies that can generate energy while pulling carbon out of the atmosphere, which is why climate planners treat it as essential rather than optional.
Why Biofuels Still Face Criticism
Biofuels are not a perfect solution. First-generation feedstocks can drive up food prices and incentivize deforestation, particularly in tropical regions where forests are cleared for palm oil plantations. The emissions savings from a biofuel can shrink dramatically, or even disappear, if producing it involves clearing carbon-rich land.
Water use is another concern. Growing energy crops requires irrigation in many regions, and processing biomass into fuel consumes additional water. There are also questions of scale: even with aggressive expansion, biofuels alone cannot replace the roughly 100 million barrels of oil the world burns every day. They are one tool in a larger toolkit that includes electrification, hydrogen, and efficiency improvements.
These criticisms don’t erase the importance of biofuels. They shape which biofuels deserve investment. The trend is clearly moving toward waste-based and advanced feedstocks that deliver deeper emission cuts without competing for farmland, and toward applications like aviation and shipping where alternatives are scarce.