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What is “Biodiesel” Fuel?

BY: Larry Witherspoon Jr.
A white car filling up at a biodiesel fueling station, which is becoming more and more popular with the push for cleaner burning fuel sources.

As we become more aware of greenhouse gases and their environmental impact, alternative fuel sources and modes of transportation are becoming increasingly popular. Fuel prices are also rising, which is also contributing to the popularity of alternative fuels. Currently, greener options include hybrid or electric vehicles, hydrogen or fuel-cell vehicles, neat ethanol vehicles, and even vehicles that run on compressed air. The good news is, if you already have a diesel-engine vehicle, shifting to a greener lifestyle is as easy as switching your fuel to biodiesel the next time you fill up.

Biodiesel is a renewable fuel available nationwide, made from readily available and diverse resources, and has many advantages. However, it isn’t the right choice for everyone. While biodiesel fuel can save you money, protect the environment and even earn you tax credit incentives, it can cause significant damage if your car isn’t equipped to handle it. Understanding what biodiesel fuel is, how it is different from petroleum diesel, and which vehicles can use it will help you determine if you should choose biodiesel options at the pump. 

What is Biodiesel Fuel?

Biodiesel is a renewable and biodegradable fuel similar to diesel but with molecular differences. Biodiesel is derived from various organic, renewable energy resources, including recycled restaurant cooking oil, vegetable oil, rapeseed oil, soybean oil, and, occasionally, animal fats (tallow). However, these chemicals alone cannot be used as fuel. 

A chemical process known as transesterification alters the chemical properties, allowing biodiesel to function nearly identically to normal diesel motor fuel while burning cleaner and releasing fewer pollutants into the atmosphere, such as hydrocarbons, carbon monoxide, and sooty particulate matter associated with diesel exhaust. It is even safer to handle overall, as it has a higher flashpoint, meaning it won’t catch on fire as easily.

The use of biodiesel in the United States has been steadily climbing, with biodiesel production increasing by 15% from 2019 to 2021. This is due to the growing interest in green fuel alternatives and renewable energy sources. As the first domestically produced, commercially available biofuel, biodiesel is available nationwide. 

Today, biodiesel is frequently blended with regular petroleum diesel in varying concentrations at the pump. Depending on the biodiesel concentration, it is usable in almost every existing diesel vehicle without requiring engine modifications. Many petroleum diesel fuel distributors add small amounts of biodiesel to their products, improving diesel lubricity and lowering sulfur content; however, drivers often seek higher concentrations. Biodiesel blends containing more than 4% biodiesel are available at many pumps, denoted with a “B” and a number indicating the percentage of biofuel. 

For example: 

  • B5: A blend of biodiesel and petroleum diesel made up of 5% biodiesel and 95% petroleum diesel; 
  • B20: A biodiesel and petroleum diesel blend of 20% biodiesel and 80% petroleum diesel. 
  • B100: 100% pure biodiesel fuel with 0% petroleum diesel. A standard diesel engine can use B100 only after making engine modifications. 

Biodiesel vs. Diesel Fuel

As a whole, consumers gravitate to diesel-powered vehicles because of their reliability and longevity, as well as their added torque and notable fuel economy. However, even with less time between fill-ups, when the diesel fuel is burned, it emits dangerous toxins into the atmosphere. Even in its blended form, biodiesel has numerous benefits to both your vehicle and the environment without any noticeable difference in performance. According to the Environmental Protection Agency (EPA), biodiesel releases 11% less carbon monoxide and 10% less particulate air toxins than petroleum diesel. Additionally, the Department of Energy and Agriculture found biodiesel reduces net carbon dioxide emissions by 78%. 

Although in its purest form, B100, biodiesel has a higher viscosity and is more likely to thicken in the cold weather of northern winter months, potentially clogging your fuel systems, biodiesel has undisputable benefits for your vehicle as well as for the environment. Because it has a higher lubricity, it is more slippery than standard diesel, resulting in less friction between moving parts and reduced wear and tear on your engine. Additionally, biodiesel raises the cetane rating, meaning the engine starts faster and easier. Overall, using high-quality biodiesel fuel can reduce maintenance and repair requirements and improve the longevity of an engine by 100%. 

Can My Car Use Biodiesel Fuel?

Not all engines are created to run on renewable biodiesel fuel. Almost 78% of diesel-powered vehicles made today can run on biodiesel fuel blends up to B20 in mild weather. This includes everything from passenger cars to heavy-duty work vehicles. If your vehicle has a petrol or gas-powered engine, putting diesel, biodiesel, vegetable oil, water, or any other incompatible fuel in your tank can result in not starting or significant damage to your engine’s essential components. 

Fortunately, putting incompatible fuel into your tank isn’t an easy mistake to make. Automobile manufacturers design the filler neck and the pump’s fuel nozzle with different sizing, meaning a diesel fuel nozzle should not fit into a gasoline engine tank’s filler neck. If the mistake does happen and you fill up with the wrong gas, do not turn your vehicle on. Push your vehicle away from the pump to call for roadside assistance or a tow truck. Your vehicle will need to be taken to the nearest repair shop to have the fuel emptied from the tank and the fuel lines flushed to prevent damage. 

Avoid Expensive Repairs on Gas & Diesel Vehicles with Endurance

Engine and fuel pump repairs can be expensive, like those caused by using the wrong fuel type. When you have an older, used vehicle with no factory warranty coverage, these repairs and more can also strain any budget. With the right extended car warranty or vehicle service contract, like an award-winning auto protection plan from Endurance, you can rest easy knowing you’ll be covered from unexpected breakdowns and repairs. 

Every Endurance protection plan is designed to give you peace of mind when faced with costly repair bills, even if your vehicle’s factory warranty has expired or you’ve been denied extended warrant options elsewhere. Endurance can even give you extra help and protection with additional perks not available from dealership warranty coverage. For example, all Endurance plans let you go to any certified mechanic or repair shop (including the dealership, whereas automaker coverage often keeps you limited to just the dealership for repairs

Best of all, Endurance auto protection plans come with a 30-day money-back guarantee and are customizable to fit your specific needs and budget, with basic powertrain coverage starting at just $79 per month. Plus, no matter your plan, you’ll also get a suite of additional benefits, such as 24/7 roadside assistance and towing, trip interruption coverage and rental car reimbursements. Get even more out of your plan by activating your optional Elite Benefits, which cover tire repairs/replacements, key fob replacements, and other perks and savings.

Don’t wait until you’re on the side of the road; request a FREE quote or shop online today. You can also speak directly to a member of the award-winning Endurance customer care team by calling (800) 253-8203 to get your specific questions answered. The Endurance blog can also be a great resource where you can find more helpful articles, including ways to boost your MPG, learning how the time of year can impact your fuel costs, extended warranty coverage comparisons and more.

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