Biofuels in Modern Cars: Bridging the Gap Between Fossil and Green Energy

As the automotive sector confronts stricter emissions targets, battery electric vehicles (BEVs) have dominated headlines — but biofuels remain an important transitional technology. This article examines the science, types, production pathways, vehicle compatibility, environmental trade-offs, market trends, and practical implications of scaling biofuels for modern cars. We evaluate whether biofuels are a credible bridge between fossil fuels and deep decarbonization, and highlight vehicle examples and implementation strategies that show how the technology is being deployed today.

Where Biofuels Sit in the Transport Energy Puzzle

When policymakers and automakers discuss decarbonizing road transport, two broad strategies appear: electrify the drivetrain (move to BEVs and plug-in hybrids) and decarbonize liquid fuels used by internal combustion engines (ICEs). Biofuels — liquid fuels produced from biomass through biochemical or thermochemical routes — belong to the latter approach. Biofuels can often be blended with or directly substitute petrol/diesel and are particularly attractive for vehicle fleets, legacy internal-combustion stock, and regions where rapid electrification is constrained by grid or affordability issues.

Recent years have seen steady expansion in global biofuel use and renewed interest in advanced biofuels derived from non-food feedstocks and waste residues. Yet biofuels’ climate credentials depend heavily on feedstock choice, land use impacts, and production pathways. This article walks through the technical realities, policy context, and the role biofuels can realistically play in modern cars.

What Are Biofuels? Types and Production Pathways

At the highest level biofuels for road transport are grouped into two families:

• Ethanol (alcohol-based fuels) — most commonly produced by fermenting sugars or starches (first-generation ethanol from corn, sugarcane) or from cellulosic biomass (second-generation ethanol). Ethanol blends include E10 (10% ethanol), E85 (up to 85% in flex-fuel vehicles), and higher blends or neat ethanol in specialized engines.

• Biodiesel and renewable diesel — biodiesel (fatty acid methyl esters, FAME) is produced by transesterification of vegetable oils or animal fats; renewable diesel (also called hydrotreated vegetable oil or HVO) is produced via hydrotreatment and is chemically more similar to fossil diesel, allowing drop-in use in many engines.

• Advanced biofuels — fuels made from lignocellulosic residues, algae, municipal solid waste, or via novel thermochemical/biochemical routes (e.g., Fischer-Tropsch bioderivatives, bio-jet fuels). These aim to avoid food-v-fuel tradeoffs and reduce lifecycle GHGs.

Production pathways differ in energy inputs, co-products (e.g., animal feed from ethanol mills), and overall lifecycle emissions. Modern refinements and integration with biogas, carbon capture, and improved agronomy can dramatically improve lifecycle outcomes for certain pathways.

Why Biofuels Matter Now

Biofuels already supply a non-trivial share of transport energy. In many countries, blending mandates and incentives have embedded ethanol and biodiesel into the fuel supply for decades. In 2022, biofuels accounted for roughly the low single-digit percentage of global transport energy, and analysts project meaningful growth through the late 2020s as blending rises and advanced fuels begin deployment.

Biofuels are especially important in three contexts:

1. Fleet and legacy vehicles — buses, long-haul trucks, taxis, and existing passenger cars that will remain on roads for years. Liquid fuels are easier to deploy here than retooling entire fleets for electrification.

2. Regions with constrained grids or limited BEV uptake — countries with limited electricity infrastructure or cold climates may find biofuels a pragmatic means to reduce oil imports and emissions in the short-to-medium term.

3. Rapid decarbonization of hard-to-electrify segments — biofuels (notably advanced biofuels and renewable diesel) are crucial in sectors like aviation and maritime, and offer bridging benefits for passenger vehicles too.

Vehicle Compatibility: Flex-Fuel, Blends, and Drop-In Fuels

Modern cars interact with biofuels in three principal ways:

• Blended fuels for conventional engines — many petrol engines operate with E10 (10% ethanol) without modification. Regions with higher ethanol availability use E20 or E25; however, higher blends usually require either specific engine and fuel system compatibility or designation as a flex-fuel vehicle (FFV).

• Flex-fuel vehicles (FFVs) — FFVs can run on a wide range of ethanol–gasoline blends, typically up to E85. Major automakers have produced FFVs for decades; markets like Brazil have large FFV fleets, and the U.S. has many models designated as FFVs.

• Drop-in renewable diesel and HVO — renewable diesel can be used in many diesel engines without modification, providing near-drop-in replacement characteristics and improving cold-flow properties and combustion. This makes renewable diesel attractive for heavy-duty and fleet operations.

Examples of real cars and models that illustrate these points:

• Chevrolet Trailblazer (2025) and Buick Encore GX (2025) — both listed as compatible with E85 in government alternative fuel vehicle registries.

• Large FFV fleets in Brazil — Brazilian models from local subsidiaries of automakers (e.g., Fiat, Volkswagen) have long offered engines optimized for ethanol blends.

Environmental Trade-Offs: Lifecycle Emissions and Indirect Effects

A central question is whether biofuels actually reduce greenhouse gas emissions relative to fossil fuels once full life cycles — feedstock production, land-use change, processing, transport, and co-product credits — are included. The answer varies:

• First-generation ethanol (e.g., corn ethanol) can deliver modest GHG reductions in favorable farming systems, but results depend heavily on agricultural practices and whether indirect land-use change (ILUC) is counted.

• Sugarcane ethanol (Brazil) typically shows larger GHG benefits than corn ethanol due to higher energy return and different agronomy.

• Advanced biofuels from waste, residues, or purpose-grown low-carbon feedstocks can deliver substantially larger lifecycle GHG reductions and are the most promising long-term pathway.

• Biodiesel and renewable diesel often reduce tailpipe and lifecycle GHGs compared with fossil diesel, but feedstock choice (soy, palm, waste oils) is critical; when feedstocks displace forests or peatlands, net emissions can be worse.

Economics and Scaling: Costs, Markets, and Policy Drivers

Biofuel economics rest on feedstock prices, processing capital, and policy supports (blending mandates, tax credits, carbon markets). Historically, subsidies and mandates (e.g., Renewable Fuel Standard in the U.S., blending requirements in Europe and Brazil) were essential to stimulate early markets. As advanced processing technologies improve and economies of scale emerge, unit costs fall — but capital-intensive facilities and feedstock logistics remain barriers in many regions.

International agencies forecast growth in demand for biofuels through the late 2020s, driven by policy commitments, rural economic development, and the need to reduce oil imports. Both conventional and next-generation feedstocks will be needed to meet higher blends and decarbonization scenarios.

Advanced Biofuels and Second-Generation Technologies

The most compelling promise of biofuels is from advanced routes:

• Cellulosic ethanol — uses lignocellulosic biomass (straw, wood residues, energy grasses) and avoids direct competition with food crops.

• Thermochemical routes (gasification + Fischer-Tropsch) — convert diverse biomass and waste feedstocks into hydrocarbons that are chemically similar to fossil fuels, enabling drop-in fuels for diesel and jet applications.

• Algal biofuels — long-promised but still struggling with cost and scale challenges; algae can theoretically deliver high yields on non-arable land and use wastewater, but practical barriers remain.

Co-Benefits Beyond GHGs

Biofuel deployment can deliver benefits beyond carbon:

• Energy security and trade balance — domestic biofuel production reduces dependency on imported oil in many countries.

• Rural development and jobs — biofuel value chains create agricultural and processing employment.

• Waste management — converting municipal and agricultural residues into fuel reduces waste and methane emissions from landfills.

• Compatibility with existing infrastructure — many biofuels can use current distribution channels with modest upgrades.

However, these co-benefits must be weighed against risks: water use, biodiversity impacts, and competition for arable land. Sustainable certification schemes and feedstock screening play a role in mitigating harms.

Practical Deployment Strategies

1. Improve the sustainability of feedstocks — prioritize waste, residues, and low-ILUC feedstocks.

2. Encourage drop-in renewable diesel and HVO for heavy duty fleets — immediate GHG reductions without fleet retrofits.

3. Support FFV and higher ethanol blends where local resources exist — governments can set clear blending roadmaps and standards.

4. Accelerate R&D for advanced biofuels — fund pilot and demonstration projects for cellulosic ethanol, gasification-to-liquid, and algal routes.

5. Combine biofuels with electrification — biofuels can decarbonize legacy stock while BEVs scale.

Case Studies

Brazil — sugarcane ethanol and FFVs show how domestic feedstock and supportive policy can shift a national fuel system.

United States — large installed base of E85-capable FFVs, blending mandates, and a diverse industry spanning corn ethanol and biodiesel.

Europe — renewable diesel (HVO) plays an important role in fleets and heavy-duty vehicles under sustainability frameworks.

The Role of Biofuels in Net-Zero Transport

Biofuels are unlikely to be the sole solution for passenger cars in a net-zero future dominated by electrification, but they remain a credible bridge and an essential complement — especially for legacy vehicles, heavy transport, aviation, and places where electrification is slower. Their role will depend on sustainability credentials, feedstock choices, and supportive policy frameworks.

Conclusion

Biofuels are not a silver bullet. They are one tool among many to reduce the transport sector’s reliance on fossil fuels. The future of biofuels hinges on moving away from risky, land-intensive feedstocks and toward waste, residues, and advanced conversion technologies. Paired with aggressive electrification where feasible, smart policy design, and sustainable agricultural practices, biofuels can play an important role as a bridge technology — lowering emissions in the near term while enabling deeper decarbonization strategies for the long term.

References

• International Energy Agency (IEA). Renewables and Biofuels Reports (2022–2024).

• IEA Bioenergy. Annual Report 2023.

• U.S. Environmental Protection Agency (EPA). Lifecycle Greenhouse Gas Results of Renewable Fuel Standard.

• U.S. Department of Energy, Alternative Fuels Data Center (AFDC). Vehicle Database.

• International Council on Clean Transportation (ICCT). Lifecycle Assessments of Biofuels.

• Luque, R., Lin, C.S.K., Wilson, K., & Clark, J. (Eds.). Handbook of Biofuels Production: Processes and Technologies (2nd Edition, 2016).

• Mousdale, D. M. Biofuels: Biotechnology, Chemistry, and Sustainable Development. CRC Press.

• Selected peer-reviewed studies on biodiesel and renewable diesel pathways in Environmental Science & Technology and ACS Publications.

Examples of Modern Cars Compatible with Biofuels

Manufacturer	Model	Model Year	Fuel Type Compatibility	Region/Market
Chevrolet	Trailblazer	2025	E85 Flex-Fuel	United States
Buick	Encore GX	2025	E85 Flex-Fuel	United States
Ford	F-150 FFV	2024–2025	E85 Flex-Fuel	North America
Dodge	Durango FFV	2024–2025	E85 Flex-Fuel	North America
Volkswagen	Gol (FFV)	Ongoing	Gasoline/Ethanol (up to E100)	Brazil
Fiat	Uno (FFV)	Ongoing	Gasoline/Ethanol (up to E100)	Brazil
Peugeot	208 Bioflex	2024	Ethanol Blends (up to E85)	Europe, Brazil
Scania (trucks)	R-Series (HVO)	Ongoing	Renewable Diesel (HVO)	Europe
Volvo (trucks)	FH Series	Ongoing	Renewable Diesel (HVO)	Europe
Toyota	Corolla (Brazil spec)	Recent models	Gasoline/Ethanol (up to E100)	Brazil

This table illustrates that biofuels are not only a theoretical solution but are already being used in both passenger cars and commercial vehicles.

• In the United States, E85 Flex-Fuel is widely available in SUVs and pickup trucks.

• In Brazil, popular models such as the Volkswagen Gol, Fiat Uno, and Toyota Corolla can run on high ethanol blends (up to 100%).

• In Europe, heavy-duty trucks from Volvo and Scania are already optimized for renewable diesel (HVO) without requiring modifications.

With strong policy support, sustainable feedstock availability, and integration with electrification, biofuels can serve as a realistic bridge between fossil fuels and fully green energy. Modern cars compatible with E85 and renewable diesel demonstrate that the transition is not just a future concept — it is already happening today, and scaling it further is the next logical step.