Biofuels: common questions
The questions people most often ask about biofuels — what they are, how they differ, how they’re regulated, and whether they can go in your tank.
Biofuels sit at the intersection of agriculture, chemistry, engines and policy, so the questions they raise range from the practical (“can I put this in my car?”) to the technical (“what is carbon intensity?”) to the strategic (“do these still matter in an electric age?”). The answers below cover the questions that come up most often; each links through to a fuller explanation elsewhere in this reference — the ethanol, biodiesel and advanced-fuels sections, the policy pages, and the glossary.
Biofuels: common questions
What are biofuels?
Liquid or gaseous fuels made from biomass — crops, residues, wood, oils and wastes — rather than fossil petroleum. The main ones are ethanol (for gasoline) and biodiesel and renewable diesel (for diesel engines).
What is the difference between ethanol and biodiesel?
Ethanol is an alcohol fermented from sugars and starches and blended into gasoline; biodiesel is made from oils and fats by transesterification and blended into diesel. Different chemistry, different engines.
Are biofuels renewable?
Yes — they are made from biomass that can be regrown. Their climate benefit depends on feedstock and process, measured as lifecycle carbon intensity.
Do biofuels reduce greenhouse-gas emissions?
They can, by an amount that varies widely by feedstock — from modest reductions for some crop fuels to large reductions for waste-derived and cellulosic fuels. Low-carbon fuel standards score fuels by this measure.
What is the Renewable Fuel Standard (RFS)?
The US federal policy requiring set volumes of renewable fuel to be blended into transport fuel each year, enforced through tradable RIN credits. It is the main driver of US biofuel demand.
What do E10, E15 and E85 mean?
The percentage of ethanol in gasoline: E10 (up to 10%, standard), E15 (15%), and E85 (51–83%, for flex-fuel vehicles).
What is biodiesel vs renewable diesel?
Biodiesel (FAME) is made by transesterification and used in blends; renewable diesel is made by hydrotreating into a drop-in fuel chemically near-identical to petroleum diesel.
What are first-generation and advanced biofuels?
First-generation fuels use food crops; advanced and cellulosic fuels use non-food biomass and wastes, generally with lower lifecycle carbon and land-use impact.
What is carbon intensity?
The lifecycle greenhouse-gas emissions of a fuel per unit of energy (gCO₂e/MJ) — the metric behind low-carbon fuel standards such as California’s LCFS.
Can I use biofuels in my vehicle?
Most petrol cars run on E10, and most diesels accept low biodiesel blends (B5–B20); high blends like E85 need a flex-fuel vehicle and B100 needs a compatible engine. Check manufacturer guidance.
Why are biofuels blended rather than used pure?
Blending lets renewable fuel use the existing petroleum distribution and vehicle fleet without modification, and keeps fuels within the chemistry limits of ordinary engines.
What is the food-versus-fuel debate?
The concern that using food crops for fuel competes with food supply and land. It is a central argument for shifting toward waste and cellulosic feedstocks.
Which countries produce the most biofuel?
The United States and Brazil are the two largest producers — the US predominantly corn ethanol and the European Union mainly biodiesel, while Brazil is the centre of sugarcane ethanol production.
Are biofuels the same as fossil fuels?
No. Fossil fuels come from carbon laid down over geological time; biofuels come from recently grown biomass, so the carbon they release was recently taken from the atmosphere as the feedstock grew.
Will electric vehicles make biofuels obsolete?
Biofuels and electrification address transport emissions differently. Biofuels lower the carbon of the existing liquid-fuel fleet and sectors that are hard to electrify, such as aviation and heavy transport, where sustainable aviation fuel and renewable diesel are growing.