Biodiesel and renewable diesel are both low carbon alternatives to petroleum diesel, which help to reduce emissions; however, there are key differences in their application and benefits.

Key Differences Between Biodiesel and Renewable Diesel

Biodiesel is generally produced from animal and vegetable fats and oils through a chemical reaction process known as transesterification. Biodiesel is commonly blended with petroleum diesel for use in modern diesel engines.

While Renewable diesel is also generally produced from animal and vegetable fats and oils, it undergoes a refining process similar to petroleum diesel production. This processing technique makes Renewable Diesel chemically similar to petroleum diesel, allowing it to be used as a direct replacement fuel or blended with petroleum diesel.
The majority of domestically produced and imported renewable diesel is used in California due to benefits under the Low Carbon Fuel Standard.

Production and Chemical Composition

• Renewable diesel: A hydrocarbon produced using hydrotreating, gasification, pyrolysis, and other biochemical and thermochemical technologies. It meets ASTM D975 specification for petroleum diesel and yields renewable naphtha and diesel.
• Biodiesel: Produced via transesterification, Biodiesel is a mono-alkyl ester that meets ASTM D6751 standards. It is blended with petroleum diesel, creating a product known as FAME (fatty acid methyl esters). This process also generates glycerin as a byproduct.

Performance and Efficiency

Renewable diesel provides higher power, efficiency, and compatibility with existing fuel infrastructure. It can enhance engine performance without requiring modifications. On the other hand, biodiesel, while it is environmentally friendly, may require engine adjustments due to different lubrication properties, which can lead to injector fouling.

Diesel engines are widely known for their high thermal efficiency and deliver superior fuel economy and are ideal for heavy-duty applications. They require less maintenance compared to biodiesel engines, which need additional upkeep to ensure optimal performance and longevity.

Economic and Environmental Considerations

• Cost and Availability: Biodiesel production costs can be higher due to the complex transesterification process and the need for feedstock materials. However, regional variations and government incentives may make biodiesel a cost-effective option in some areas. Diesel fuel benefits from a well-established global distribution network, giving it a significant accessibility advantage.
• Emissions and Sustainability: Diesel engines emit higher levels of nitrogen oxides (NOx) and particulate matter (PM), contributing to air pollution and respiratory health concerns. In contrast, biodiesel produces lower NOx and PM emissions, aligning with efforts to improve air quality. Both biodiesel and renewable diesel significantly reduce greenhouse gas emissions compared to petroleum diesel.

Advantages of Biodiesel and Renewable Diesel

• Renewable Resource: Both fuels are derived from sustainable feedstocks such as waste fats and vegetable oils, reducing dependence on fossil fuels.
• Lower Carbon Footprint: Biodiesel and renewable diesel emit fewer greenhouse gases, helping mitigate climate change.
• Biodegradability: Biodiesel is biodegradable, lowering environmental risks in case of spills.
• Economic Benefits: Locally sourced feedstock supports agricultural industries and promotes a circular economy.

Final Thoughts

Both biodiesel and renewable diesel offer compelling advantages for consumers and businesses seeking sustainable fuel options. While renewable diesel provides superior performance and compatibility, biodiesel remains a viable, eco-friendly choice with lower emissions. The choice between the two depends on operational needs, infrastructure, and regulatory incentives.