Biofuels: The Real-World Pros and Cons

Biofuels can cut oil use and greenhouse gases when sourced from wastes and residues or advanced feedstocks, but crop-based fuels can deliver modest or even negative climate outcomes if they drive land-use change, while also posing trade-offs in air quality, water, and food markets. This article explains where biofuels help most, where they fall short, and what determines their sustainability as policymakers push cleaner fuels for aviation, trucking, and beyond.

What Counts as a Biofuel Today

Biofuels are liquid and gaseous fuels made from biological material. The most common are ethanol (typically from corn or sugarcane) blended into gasoline; biodiesel (FAME) and renewable diesel (HVO) for diesel engines; biogas/renewable natural gas from wastes; and emerging sustainable aviation fuels (SAF). “First‑generation” fuels use food crops; “advanced” or “second/third‑generation” fuels come from residues, wastes, lignocellulosic biomass, or algae. Global production reached record levels in 2023–2024, with renewable diesel and SAF expanding quickly from a small base, while electrification erodes demand for biofuels in light-duty cars. SAF remains a tiny share of jet fuel today—well under 1% globally—but mandates in the U.S., EU, and UK are set to raise supply through the late 2020s.

The Pros of Biofuels

The following points summarize the main advantages that make biofuels attractive to governments and industry, especially for hard-to-electrify sectors.

• Lower lifecycle greenhouse gases (with the right feedstocks): Waste- and residue-based fuels, renewable diesel from used cooking oil or animal fats, cellulosic ethanol, and biogas can cut emissions substantially relative to fossil fuels; some manure-based RNG pathways can even be net carbon-negative when methane capture is credited.
• Drop-in compatibility and fast deployment: Renewable diesel (HVO) and many SAF pathways can be used in existing engines and pipelines with minimal modifications, enabling rapid decarbonization compared with infrastructure-heavy alternatives.
• Air-quality benefits in many cases: Compared with petroleum diesel, renewable diesel often lowers particulate matter and sometimes NOx; biodiesel can reduce soot and CO; ethanol lowers CO and certain aromatics in gasoline blends.
• Waste valorization and rural economic benefits: Turning agricultural residues, municipal organic waste, landfill gas, and used cooking oil into fuel reduces disposal burdens and creates revenue streams and jobs in farming and refining communities.
• Energy security and diversification: Domestic biofuels can reduce exposure to oil price shocks and import dependence, leveraging existing refinery and distribution assets.
• Decarbonizing hard-to-abate segments: Aviation, long-haul trucking, and some marine uses have fewer near-term alternatives; drop-in low-carbon fuels allow immediate progress toward sectoral targets.

Taken together, these advantages explain why biofuels feature in many national climate plans: they provide tangible, near-term reductions and can be tuned to use local feedstocks and existing infrastructure.

The Cons of Biofuels

These drawbacks highlight why outcomes vary widely by fuel type and context, and why strong sustainability rules matter.

• Land-use change and biodiversity risks: Expanding cropland for fuel (e.g., palm, soy, maize) can drive deforestation or grassland conversion, releasing large stores of carbon and harming ecosystems; indirect land-use change (ILUC) remains a major uncertainty.
• Modest or uncertain climate benefits for some fuels: Corn ethanol and crop-based biodiesel can deliver small gains—or losses—once fertilizer inputs, nitrous oxide emissions, and land-use change are included; results differ by region and farming practices.
• Food-versus-fuel and price volatility: Diverting edible oils or grains to fuel can tighten food markets, raising prices and increasing vulnerability for low-income consumers, especially during droughts or supply shocks.
• Water use and pollution: Irrigation demands, fertilizer runoff, and pesticide use can strain water supplies and worsen eutrophication; residue removal can reduce soil carbon if not managed carefully.
• Air pollutant trade-offs: Biodiesel blends can raise NOx in some engines; ethanol use increases acetaldehyde emissions; cold-start behavior and evaporative emissions need management to protect local air quality.
• Engine and infrastructure challenges: Biodiesel has cold-flow and oxidation stability limits; ethanol’s lower energy density reduces mileage and faces “blend walls”; material compatibility and microbial growth require controls.
• Cost and scalability constraints: Truly sustainable lipid feedstocks (waste oils, tallow) are limited; advanced pathways (cellulosic ethanol, FT fuels) remain costlier and technically complex at scale; feedstock competition can cap growth.
• Policy dependence and verification risks: Many projects rely on credits (RFS, LCFS, SAF incentives); ensuring real carbon intensities, preventing double counting, and avoiding fraud demand robust monitoring and certification.

These concerns do not rule out biofuels, but they limit the role of crop-based options and put a premium on advanced processes, credible sustainability certification, and careful deployment.

What Determines Whether a Biofuel Is Sustainable

Several factors largely explain why some biofuels deliver strong climate and environmental benefits while others do not.

• Feedstock hierarchy: Prioritize wastes and residues (used cooking oil, animal fats, municipal organics, manure, crop residues, forestry slash) over food crops; avoid feedstocks linked to deforestation or peatland drainage.
• Conversion technology and energy inputs: Efficient hydrotreating (HVO), gasification–Fischer–Tropsch, and cellulosic processes powered by low-carbon electricity/heat lower carbon intensity; integrating carbon capture can push some pathways net negative.
• Local context and land management: Use marginal/degraded lands where appropriate; retain sufficient residues for soil health; deploy cover crops and precision fertilizer to cut nitrous oxide and protect soil carbon.
• Co-product accounting: Treatment of distillers grains, electricity co-generation, and biochar affects lifecycle results; transparent, conservative allocation methods reduce greenwashing.
• Certification and policy safeguards: EU RED II/III sustainability criteria, CORSIA for aviation, U.S. RFS categories and California LCFS carbon-intensity scoring help screen out high-ILUC pathways and reward verified emission cuts.
• Sector prioritization: Direct scarce low-carbon liquid fuels to aviation, marine, and heavy-duty uses where electrification is hardest; rely on EVs and efficiency in light-duty road transport.

In practice, the best outcomes pair the right feedstocks with efficient, low-carbon processes and strong oversight, while steering limited supplies to the highest-impact end uses.

By the Numbers: Typical Lifecycle Emission Ranges

Lifecycle greenhouse-gas performance varies widely; the ranges below reflect commonly reported values in regulated markets, with results sensitive to local practices and whether land-use change is included.

• Corn ethanol (U.S.): About 20–40% lower than gasoline on average; best-in-class farms and plants approach ~50% reductions; outcomes can worsen if land-use change or high nitrous oxide emissions are significant.
• Sugarcane ethanol (Brazil): Roughly 60–90% lower than gasoline, especially where bagasse powers mills and fields avoid expansion into high-carbon ecosystems.
• Soy biodiesel: Typically 40–70% lower than petroleum diesel; results degrade with land-use change; palm biodiesel can be worse than fossil diesel if associated with deforestation or peat impacts.
• Renewable diesel (HVO) from waste oils/fats: Often 60–90% lower than fossil diesel; limited by availability of sustainable lipids.
• Cellulosic ethanol and FT fuels from residues/energy crops: Commonly 70–100% lower; can be net-negative with carbon capture and careful soil carbon management.
• Biogas/RNG from manure, landfill gas, or wastewater: Around 60% lower to strongly net-negative when methane capture prevents fugitive emissions otherwise released to the atmosphere.
• SAF (HEFA from waste lipids): Frequently ~50–80% lower than conventional jet; alcohol-to-jet and FT routes from residues can reach similar or higher reductions when powered by low-carbon energy and hydrogen.

These ranges underscore why policy frameworks increasingly reward carbon intensity on a pathway-by-pathway basis rather than treating all biofuels as equal.

When Biofuels Make the Most Sense

Strategic use can maximize climate benefits and minimize trade-offs. The following practices reflect a consensus emerging in policy and industry.

• Use waste and residue feedstocks first, with strong traceability to avoid indirect impacts.
• Target aviation, marine, and long-haul trucking; continue rapid electrification of cars, urban buses, and short-haul trucks.
• Co-locate plants with low-carbon power/heat, integrate carbon capture where feasible, and leverage refinery co-processing for rapid scale-up.
• Protect high-carbon and high-biodiversity landscapes; adopt regenerative agriculture, cover crops, and conservative residue removal to preserve soil health.
• Employ performance-based policy (e.g., LCFS, CI-based tax credits) to drive real emission cuts and continuous improvement.

Deployed this way, biofuels complement electrification rather than compete with it, focusing scarce low-carbon molecules where they have the greatest value.

Outlook for 2025 and Beyond

Policy is the prime mover. In the United States, the Inflation Reduction Act transitions to a technology-neutral clean fuel production credit (45Z) from 2025–2027 that pays per unit of verified carbon-intensity reduction, while a separate SAF credit is pushing early aviation supply. The EU’s ReFuelEU Aviation requires SAF blending to rise from 2025, with steep increases through 2030 and beyond; RED III tightens sustainability rules and targets advanced fuels; the UK is rolling out its SAF mandate. Subnational clean fuel standards (e.g., California’s LCFS and similar programs in Canada and additional U.S. states) continue to reward the lowest-carbon pathways, particularly waste-based renewable diesel and RNG.

Growth will remain constrained by sustainable feedstock supply and project finance for advanced conversions. Renewable diesel capacity is expanding, but waste oils and animal fats are limited; crop oils raise ILUC concerns. Cellulosic and gasification-based fuels are scaling, though capital-intensive. SAF will grow from a very small base to meet early mandates, with HEFA dominating near term and alcohol-to-jet and FT routes emerging later. Meanwhile, accelerating electric vehicles will reduce the role of ethanol and biodiesel in light-duty transport, sharpening the focus on heavy-duty, marine, and aviation markets.

Summary

Biofuels are not a monolith: their benefits depend on what they’re made from, how they’re produced, and where they’re used. Wastes and residues converted with efficient, low-carbon processes can deliver deep cuts in transport emissions and improve air quality, especially in aviation and heavy-duty sectors. In contrast, fuels that expand cropland can undermine climate goals, stress water and biodiversity, and pressure food markets. The most effective path forward prioritizes verified low-carbon pathways, robust sustainability safeguards, and targeted use where clean molecules—not electrons—are most needed.

What are 5 disadvantages of biodiesel?

Cons of Biodiesel:

• Tailpipe Emissions. Assets that run on biodiesel still have tailpipe emissions.
• Can be More Expensive. The cost of biodiesel depends on the blend level and the feedstocks.
• Gels in Cold Weather. Higher blends of biodiesel gel in the engine in cold weather.
• Not Available Everywhere.

What are the three advantages of using a biofuel?

In conclusion, biofuels offer several advantages, including being a renewable energy source, emitting fewer greenhouse gases, promoting domestic production and energy security, and creating new job opportunities.

What are the pros and cons of biofuels?

Biofuels offer advantages like being a renewable energy source, reducing dependence on fossil fuels, and creating local jobs. However, they also have significant drawbacks, including high production costs, intensive land and water use that can lead to deforestation and impact food security, potential water and air pollution during production, and sometimes lower energy efficiency compared to fossil fuels. 
Advantages

• Renewable: Biofuels are derived from organic matter, such as plants, crops, and animal waste, making them a renewable resource that can be regrown or replenished. 
• Reduced Fossil Fuel Dependence: Using biofuels can decrease a nation’s reliance on imported fossil fuels, improving energy security. 
• Local Job Creation: The production of biofuels can stimulate local economies by creating jobs in farming, harvesting, and processing. 
• Waste Reduction: Some biofuels can be produced from agricultural or food waste, which provides a more sustainable way to dispose of these materials. 
• Potentially Cleaner Emissions: Biofuels can result in lower greenhouse gas emissions compared to some fossil fuels, though the total benefit depends on the feedstock and production process. 

Disadvantages

• Land and Water Use: Large-scale biofuel production requires significant amounts of land and water, which can lead to competition with food production and increased water scarcity. 
• Food Security Impact: Using arable land for growing biofuel crops can reduce the land available for producing food, potentially leading to higher food prices and impacting global food security. 
• Environmental Concerns: Production processes for biofuels can contribute to environmental problems such as deforestation, habitat destruction, and water pollution from fertilizers and pesticides. 
• High Production Costs: The energy and resources needed for growing, harvesting, and converting biomass into fuel can be substantial, leading to high production costs. 
• Energy Return on Investment: The energy required to produce some biofuels may be greater than the energy they yield, a factor known as low Energy Return on Investment (EROI). 
• Infrastructure and Compatibility: Many vehicles may require modifications to use certain biofuels, and there is a general lack of widespread infrastructure compared to conventional fuels. 

What are the negative impacts of biofuels?

Biofuel production and use has drawbacks as well, including land and water resource requirements, air and ground water pollution. Depending on the feedstock and production process, biofuels can emit even more GHGs than some fossil fuels on an energy -equivalent basis.