Biofuel pros and cons: where they help, where they hurt

Biofuels can reduce lifecycle greenhouse-gas emissions—often by 20% to 90% compared with fossil fuels—especially when made from wastes and residues, but their benefits vary widely and can be outweighed by land-use change, food and water impacts, air-pollutant trade-offs, limited sustainable feedstocks, and higher costs. This article explains the main advantages and drawbacks, the types of biofuels in use today, and when biofuels are most—and least—effective for climate and energy goals.

What counts as a biofuel?

Biofuels are liquid or gaseous fuels derived from biological material. Different pathways deliver very different environmental and performance outcomes, so it’s important to distinguish among them.

• Ethanol (e.g., corn in the U.S., sugarcane in Brazil): blended with gasoline (E10, E15) or used as high-ethanol fuel (E85) in flex-fuel vehicles.
• Biodiesel (FAME): produced via transesterification of vegetable oils or animal fats; typically used in blends like B5–B20.
• Renewable diesel (HVO): a “drop-in” diesel substitute made by hydrotreating oils/fats; can be used up to 100% in compatible engines.
• Sustainable aviation fuel (SAF): jet-fuel-range hydrocarbons from approved pathways (e.g., HEFA from waste oils, ATJ from alcohols, FT from biomass); currently blended up to 50% under ASTM specifications.
• Biogas/Renewable natural gas (RNG): methane from anaerobic digestion of organic waste, upgraded and injected into pipelines or used on-site.
• Cellulosic/advanced biofuels: fuels from agricultural residues, forestry waste, energy grasses, or municipal solid waste; typically offer higher GHG cuts but remain supply-constrained.

Each category comes with different feedstocks, infrastructure needs, and environmental profiles. Waste- and residue-based fuels generally deliver the strongest climate performance and avoid most land-use concerns.

Advantages of biofuels

The case for biofuels hinges on decarbonizing difficult sectors, leveraging existing engines and infrastructure, and capturing methane and waste streams that would otherwise emit potent greenhouse gases.

• Lower lifecycle GHG emissions: Waste- and residue-based fuels (e.g., used cooking oil renewable diesel, manure-based RNG) often cut emissions by 60–90% or more; some manure-to-RNG pathways can achieve net-negative emissions by capturing methane.
• Drop-in capability: Renewable diesel and many SAF pathways work in existing engines and aircraft as blended fuels, enabling near-term reductions without wholesale equipment replacement.
• Hard-to-electrify sectors: Aviation, maritime, and some heavy-duty applications can use biofuels where batteries or hydrogen are not yet practical at scale.
• Waste management benefits: Turning organic waste into fuel reduces landfill methane, a potent greenhouse gas, and can reduce open burning or improper disposal of residues.
• Energy security and rural economies: Diversifies fuel supply, can support farm and forestry incomes, and uses domestic waste streams.
• Policy alignment and incentives: In many regions, low-carbon fuel standards and tax credits reward fuels with verified low carbon intensity.

These strengths make biofuels a pragmatic bridge in the energy transition—particularly when sourced from verified sustainable feedstocks and directed to sectors with few alternatives.

Drawbacks and risks

Not all biofuels are created equal. Some pathways deliver modest or even negative climate results when indirect effects and local environmental impacts are considered.

• Land-use change and deforestation: Expanding cropland for fuel can displace food production, drive deforestation, and release large carbon stocks, eroding or reversing climate benefits.
• Food vs. fuel pressure: Using edible crops for fuel can tighten food markets and incentivize monocultures, with knock-on effects on prices and nutrition.
• Biodiversity and water stress: Large-scale feedstock production can reduce habitat diversity and increase water withdrawals and agrochemical runoff.
• Air-pollutant trade-offs: Biodiesel can increase NOx compared with petroleum diesel in some engines, even as it tends to lower particulate matter and CO; ethanol blends can alter VOC profiles and aldehydes.
• Limited sustainable feedstocks: Truly low-carbon, waste-based supplies are finite; scaling beyond wastes risks sustainability compromises.
• Engine and infrastructure limits: Ethanol’s lower energy density and material compatibility issues cap blends in conventional vehicles; biodiesel faces cold-flow and storage stability constraints.
• Cost premiums: SAF and renewable diesel often cost more than fossil counterparts, relying on incentives; supply can be volatile.
• Accounting uncertainties: Indirect land-use change and fertilizer-related nitrous oxide (a potent GHG) introduce uncertainty in lifecycle assessments; methane leakage can reduce RNG benefits.

These risks underscore why sustainability criteria, accurate lifecycle accounting, and careful feedstock choices are essential when deploying biofuels at scale.

How big are the climate benefits, really?

Lifecycle performance varies by pathway and practice. Typical ranges from recent policy-grade models show:

• Corn ethanol: roughly 20–45% lower GHG than gasoline under efficient farming and modern plants; results can be weaker if land-use change or fertilizer emissions are high. Sugarcane ethanol commonly achieves 50–70% reductions.
• Cellulosic ethanol (residues/energy grasses): about 60–90% reductions, depending on process energy and logistics.
• Biodiesel (soy/canola): often 50–70% reductions; from used cooking oil or tallow, typically 70–90%.
• Renewable diesel (HVO): generally 60–90% reductions for waste/residue feedstocks; lower when using dedicated oil crops with land-use effects.
• SAF: HEFA SAF from waste oils often 60–80% lower than jet fuel; other approved pathways vary widely and are currently blend-limited.
• RNG/biogas: 60–100%+ reductions are common; manure-based projects can achieve net-negative emissions when methane capture is credited and leakage is minimized.

Outcomes depend on local agronomy, feedstock transport distances, plant efficiency, co-product handling, and the electricity or heat used in refining. Certification systems and carbon-intensity scoring help differentiate high- from low-performing fuels.

Scalability: what can be done sustainably?

Modern bioenergy is already the largest renewable in final energy consumption, but expanding sustainably is challenging. Waste and residue feedstocks—used oils, animal fats, forestry and ag residues, municipal organic waste—offer strong climate performance yet are limited in volume and geographically dispersed. Dedicated energy crops can add supply but raise land-use, water, and biodiversity concerns if not carefully sited on marginal lands and managed with regenerative practices.

Most decarbonization roadmaps prioritize: 1) maximizing efficiency and electrification where feasible; 2) reserving scarce low-carbon biofuels for aviation, maritime, and certain heavy-duty or off-grid uses; and 3) tightening sustainability criteria to steer investment toward the best-performing pathways.

Policy snapshot (2024–2025)

Policies are increasingly steering biofuels toward higher sustainability and hard-to-electrify sectors:

• European Union: RED III strengthens sustainability criteria and caps food- and feed-based biofuels; ReFuelEU Aviation requires rising SAF shares (2% in 2025, 6% by 2030, 20% by 2035, higher thereafter) with sub-quotas for synthetic fuels later in the decade.
• United States: The Renewable Fuel Standard continues to set volume and category targets; Low Carbon Fuel Standards (e.g., California) reward fuels with verified low carbon intensity; the Inflation Reduction Act provides SAF and clean fuel production credits through the mid-2020s, tied to lifecycle performance.
• Global aviation: ICAO’s CORSIA program began its first phase in 2024, allowing eligible SAF to reduce airlines’ offsetting obligations when sustainability criteria are met.

These frameworks increasingly favor waste- and residue-based fuels with robust verification and discourage high-ILUC feedstocks, shaping where investment flows.

When biofuels make the most sense

Biofuels deliver the greatest value when they displace fossil fuels in sectors without ready electric alternatives and when they come from feedstocks that avoid land-use change and minimize local environmental harms.

• Aviation and long-haul maritime: SAF and renewable fuels provide immediate drop-in blends, with infrastructure already in place at hubs.
• Heavy-duty and off-road equipment: Renewable diesel can cut emissions quickly in existing fleets, particularly in regions with LCFS-type policies.
• Waste methane mitigation: RNG from manure, landfill gas, and wastewater can yield large—sometimes net-negative—GHG impacts when methane capture is additional and leakage is tightly controlled.
• Local residues: Fuels made from regional agricultural or forestry residues reduce transport emissions and land-use risks.

In light-duty transport with strong EV options, electrification typically delivers larger, cheaper, and more reliable emission cuts than expanding crop-based biofuels.

Practical guidance for buyers and fleets

For organizations and consumers considering biofuels, due diligence on carbon intensity and sustainability can make the difference between meaningful and marginal benefits.

• Favor certified waste/residue pathways (e.g., used cooking oil, tallow, residues) with verified low carbon intensity scores.
• Check blend limits and warranties: E10/E15 for most cars, E85 for flex-fuel; B5–B20 for biodiesel depending on climate and engine; renewable diesel is generally drop-in where available.
• Mind cold-flow and storage: Biodiesel needs winterization; microbial growth and oxidation can be managed with good housekeeping.
• Track air-quality impacts: In NOx-sensitive areas, renewable diesel often performs better than biodiesel while still cutting PM.
• Use policy tools: Low-carbon fuel standards and tax credits can close cost gaps; require suppliers to provide third-party sustainability certification and carbon-intensity data.

Aligning procurement with robust standards and local air-quality needs helps ensure biofuel use contributes to both climate and health goals.

Summary

Biofuels can play a targeted, near-term role in cutting emissions—especially SAF, renewable diesel, and RNG from waste streams—by leveraging today’s engines and infrastructure. Their downsides arise when scaling pushes into land-intensive feedstocks, undermining climate and ecological goals and straining food and water systems. The best outcomes come from prioritizing waste- and residue-based fuels, directing them to hard-to-electrify sectors, enforcing strong sustainability and lifecycle accounting, and pairing deployment with continued electrification and efficiency across the economy.

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 is the main problem with biofuels?

A significant problem with biofuels is the competition for land and water resources with food production, which can lead to increased food prices, food insecurity, and deforestation to create new farmland for biofuel crops. Furthermore, biofuel production and burning can release air pollutants like ozone and nitrogen dioxide, posing risks to public health. 
Competition for Resources

• Food Prices and Security: Opens in new tabGrowing crops for biofuels requires vast amounts of land, water, and fertilizers, diverting these resources from food production. This reduced supply of food crops can drive up prices, threatening food security, especially in lower-income countries. 
• Deforestation and Habitat Loss: Opens in new tabTo expand biofuel crop cultivation, natural habitats like forests and grasslands are often cleared. This deforestation leads to habitat destruction, loss of biodiversity, and the release of stored carbon from trees into the atmosphere. 
• Water Strain: Opens in new tabThe large volumes of water needed for growing biofuel crops and refining them can deplete underground aquifers, which are also used by farmers for irrigation. 

Health and Environmental Impacts 

• Air Pollution: Opens in new tabThe burning of biofuels and emissions from biofuel refineries can release toxic particles, ozone, and nitrogen dioxide into the air. These pollutants can trigger respiratory illnesses like asthma and are associated with heart attacks, cancer, and premature death, particularly affecting vulnerable groups like the elderly and children. 
• Soil Degradation and Water Contamination: Opens in new tabThe intensive farming practices often used for biofuel crops, such as monoculture, can lead to soil degradation. Runoff from fertilizers and pesticides used to grow these crops can also pollute soil and water sources. 
• Greenhouse Gas Emissions: Opens in new tabWhile often presented as a carbon-neutral alternative, the process of producing and refining biofuels can result in significant greenhouse gas emissions, sometimes comparable to or even exceeding those of fossil fuels, especially when deforestation and land-use changes are involved. 

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 biofuels?

Biofuels are energy sources derived from renewable organic matter (biomass), such as plants, algae, and organic waste, that can be used in place of fossil fuels like gasoline and diesel. Common types include bioethanol, made from fermenting sugars in crops like corn or sugarcane, and biodiesel, produced from vegetable oils or animal fats. Biofuels offer a potential way to reduce greenhouse gas emissions and dependence on finite fossil fuels, though they also present challenges related to land use, competition with food production, and overall sustainability.
 
How Biofuels Are Made
Biofuels are produced through various methods, often involving: 

• Biochemical Conversion: This process uses microorganisms and enzymes to ferment sugars and starches found in biomass, such as grains and plant materials, into ethanol. 
• Thermo-chemical Conversion: Methods like pyrolysis and gasification involve heating biomass in an oxygen-free or controlled oxygen environment to break it down into bio-crude oil or syngas, which can then be refined into fuels. 

Common Types of Biofuels

• Bioethanol: Produced by fermenting sugars from corn, sugarcane, wheat, and other crops. 
• Biodiesel: Made from vegetable oils (like soybean or palm oil), animal fats, and used cooking oils. 
• Biogas: A mixture of gases, primarily methane, produced from the anaerobic decomposition of biomass, such as cow manure. 

Benefits and Challenges

• Benefits: Biofuels are renewable and can help reduce reliance on fossil fuels, offering a path toward energy independence and potentially lower greenhouse gas emissions. 
• Challenges:
  • Land Use: Producing biofuels requires land, which can lead to competition with food production. 
  • Sustainability Concerns: The energy and resources needed to grow and process crops for biofuels can sometimes offset their environmental benefits, particularly in first-generation biofuels, notes the Understand Energy Learning Hub. 
  • Economic Viability: Developing more efficient and cost-effective methods for sustainable biofuel production remains an ongoing focus for researchers.