What Is Biodiesel and Is It the Future of Diesel?

Reviewed by

Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Written by CarParts.com Research Team - Updated on February 3rd, 2024

Reading Time: 5 minutes
Summary
  • Biodiesel is a combination of modified vegetable oils and diesel fuel. It aims to replace non-renewable fuels.
  • Most biodiesel comes from used vegetable oil sourced from fast food restaurants and industrial food manufacturers.
  • Biodiesel works for all conventional vehicles, but higher-level blends aren’t recommended by certain vehicle manufacturers.

Rising fuel prices and climate change might have made you wonder about the benefits of using biodiesel on your vehicle. Read on to learn more about biodiesel, how it’s made, its pros and cons, and whether it is the future of diesel.

What Is Biodiesel?

Biodiesel is a biodegradable alternative fuel created from a combination of modified vegetable oils and diesel fuel. Biodiesel can also be made from tallow, algae, canola, and animal fats. The goal of biofuels is to replace traditional non-renewable fuels with those derived from plant material or other renewable feedstocks. Biodiesel is now incorporated at a 5% rate in practically all diesel fuel sold in the United States.

Biodiesel is a biodegradable alternative fuel created from a combination of modified vegetable oils and diesel fuel.

How Is Biodiesel Made?

The majority of biodiesel generated today is made from used vegetable oil sourced from fast food restaurants, and industrial food manufacturers. Waste vegetable oil from these sources must be processed before being converted to biodiesel to eliminate pollutants like food particles. Waste vegetable oil is typically obtained for free, while processed oil is available at a low cost.

Transesterification is a chemical process where glycerin is extracted from either fat or vegetable oil. The process produces glycerin and one other byproduct, methyl ester, which is basically biodiesel.

Which Vehicles Can Use Biodiesel?

All conventional diesel vehicles can run biodiesel. However, some vehicle manufacturers don’t approve the use of higher-level blends of biodiesel.

The most popular biodiesel mix is B20, which contains 20% biodiesel and 80% petroleum. Another biodiesel blend is B5, which is composed of 5% biodiesel and 95% diesel. Many diesel cars can run on B20 and lower-level blends without needing engine modifications.

However, just because your vehicle can run it, doesn’t mean you should. You have to do your research on what biodiesel your vehicle can support. There are many stories of vehicle owners using biodiesel haphazardly and damaging their engines. Moreover, you have to make sure that you’re getting biodiesel from a reliable source, as some biodiesel might have impurities that can damage your vehicle’s fuel system.

When it comes to using biodiesel, you have to really research what your vehicle can support… You also have to make sure you are getting it from a reliable source, and always get it from that source.

Anthony Harlin, ASE Certified Master Automobile Technician

Pros of Using Biodiesel

Compared to traditional, petroleum-based fuels, biodiesel offers several advantages. 

Since biodiesel is sourced from renewable sources like vegetables and livestock, it can be sourced domestically. As a result, using biodiesel can lessen the US’ dependence on foreign oil. 

Biodiesel also minimizes tailpipe emissions such as soot and air toxins. According to the Environmental Protection Agency (EPA), biodiesel emits 10% less particulate matter and 11% less carbon monoxide than conventional diesel. Another study by the Department of Energy and Agriculture states that biodiesel reduces net carbon emissions by 78%.

Cons of Using Biodiesel

Despite these advantages, biodiesel also has a few downsides.

Some mechanics tend to dislike biodiesel because they’ve observed that it can damage engines over the long run. Engines do run into a fair amount of wear and tear over time, but biodiesel seems to wear out engines at a significantly faster rate. It isn’t uncommon for a diesel engine running biodiesel to suddenly find that the engine or fuel system is wrecked beyond repair.

Many diesel vehicles weren’t originally intended to run biodiesel. As a result, this initially brought up many questions regarding biodiesel’s long-term effects on engines. People have also expressed concerns regarding biodiesel’s quality. In response, the National Biodiesel Board has collaborated with regulators, car and engine manufacturers, and the biodiesel industry to create standards for pure biodiesel and biodiesel blends.

Another major concern with biodiesel is its storage. Biodiesel must be stored at a certain temperature. If the temperature is too hot, it can grow mold. If the temperature is too cold, the fuel can thicken and become difficult for pumps to dispense.

Biodiesel-powered vehicles have also been reported to perform poorly in cold conditions. Additionally, biodiesel can cause fuel filter clogs because it can release deposits on fuel tank walls and pipes.

Biofuel might be a superior source of energy compared to oil given that it’s renewable, biodegradable, and less harmful to the environment, but it’s probably not a long-term solution.

Is Biodiesel the Future of Diesel?

The production of biodiesel has increased dramatically from 2005 to the present. In 2018, the biodiesel industry in the United States produced 2.6 billion gallons of biodiesel. In 2011, the International Energy Agency forecasted that biofuels could make up 27% of global transportation fuels by 2050.

However, utilizing farmland to create fuel rather than food presents its own set of issues. Energy solutions that rely on waste or other feedstocks have yet to compete in terms of price and scale versus traditional fuels. To satisfy the International Energy Agency’s objectives for sustainable growth, global biofuel output must quadruple by 2030. 

Despite biodiesel’s growing adoption, it may all be for naught. Some people in the energy industry believe that hydrogen, not diesel or even biodiesel, might be the future energy source of choice for heavy transport and road freight. According to a report commissioned by Shell, 158 executives in the road freight industry believe hydrogen will be the more cost-effective and practical approach to net-zero emissions for heavy-duty and long-route medium-duty vehicles. 

The future of biodiesel looks even more bleak as major European truck manufacturers have moved the goal date for the phase-out of diesel engines from 2050 to 2040. Since biodiesel is mostly run by diesel engines, the phrase out of diesel engines will surely affect biodiesel adoption and use.

Put simply, biodiesel doesn’t seem to be as attractive as hydrogen and electrification when it comes to being a future energy source. 

Biofuel might be a superior source of energy compared to oil given that it’s renewable, biodegradable, and less harmful to the environment. However, using biodiesel is probably not a long-term solution. Even with biodiesel’s low net emissions compared to traditional fuel, its net emissions are still considerably higher compared to other energy sources.

Biodiesel is more likely to have a larger role in the short term since many vehicle manufacturers are intending to stop producing internal combustion engine vehicles. The world’s long-term goal is more focused on other low-carbon technology like electrification and hydrogen.

About The Authors
Reviewed By Anthony Harlin, ASE Certified Master Automobile Technician

Technical Reviewer at CarParts.com

Tony Harlin is a Master Gas and Diesel Diagnostic Technician with over 18 years of experience. He works full-time at a large independent automotive shop as a driveability and repair technician working on all types of vehicles with a focus on diesels. ASE certifications include A1-A9, L1 and L2, as well as X1.

Written By CarParts.com Research Team

Automotive and Tech Writers

The CarParts.com Research Team is composed of experienced automotive and tech writers working with (ASE)-certified automobile technicians and automotive journalists to bring up-to-date, helpful information to car owners in the US. Guided by CarParts.com's thorough editorial process, our team strives to produce guides and resources DIYers and casual car owners can trust.

Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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Published by
CarParts.com Research Team and Anthony Harlin, ASE Certified Master Automobile Technician