Renewable Diesel, Biodiesel and the Clean Fuels Boom

September 26, 2023

Renewable diesel production has quadrupled in recent years, and that growth is expected to accelerate. Annual U.S. capacity has increased from 600 million gallons in 2019 to 2.63 billion gallons in 2022, according to economists at the University of Illinois at Urbana-Champaign. They project it will reach 4.1 billion gallons in 2023. That’s nearly seven times the increase in production in four years.

The benefits of renewable diesel are far-reaching. Major corporations and municipalities are making the switch to cleaner fuels, reducing their emissions and impact on the environment and human health. This growth is also bolstering the economy and job availability in rural communities with companies investing over $6 billion in additional soybean crush facilities.

Making fuels out of plants and animal fats isn’t something new—biodiesel has been a billion-gallon industry in the United States for a decade. So, why are clean fuels suddenly booming?

Defining the Difference

It’s important to understand that biodiesel and renewable diesel aren’t variations of the same fuel. Both start with bio-based feedstocks, such as vegetable oils or animal fats, but a different refining process gives each fuel its own superpower.

The primary advantage of renewable diesel is its ease of use. It is produced through a high-heat, high-pressure process that gives it similar chemical properties to diesel fuel. It’s a straight replacement for petroleum-based diesel fuel, only cleaner-burning. An engine running on regular diesel fuel can switch to renewable diesel without any modifications and immediately cut its emissions.

Biodiesel is produced through a process called transesterification, which separates glycerin from the vegetable oils or fat used for feedstock. The remaining chemical, called methyl esters, is used as biodiesel, while the extracted glycerin is used for products like soap. Some engines are approved for 100% biodiesel, but many require upgraded systems to run on these higher blends. Most vehicles are rated for lower blends like B20, a blend of 20% biodiesel and 80% petroleum diesel.

So, if renewable diesel is a drop-in replacement for petroleum, why would someone choose biodiesel? When it comes to the goal of lowering emissions, biodiesel is more of a good thing. Both fuels reduce greenhouse gas (GHG) emissions by more than 70% on average, but biodiesel provides superior reductions in particulate matter, aromatic compounds and carbon monoxide, as well as improved lubricity for an engine.

These fuels can work in tandem to produce a cost-effective fuel replacement option for petroleum diesel. Because renewable diesel is a direct replacement for petroleum diesel, a vehicle that is approved for B20 can run on a blend of 20% biodiesel and 80% renewable diesel, which would generate the greatest reduction in emissions without changing equipment.

Fueling the Future

Clean fuels provide opportunities and fast solutions to our growing climate crisis. Renewable diesel’s projected growth is due to its ability to fill the portion of the tank currently occupied by petroleum while blending in biodiesel can further cut emissions. For most heavy-duty vehicles, such as semi-trucks, construction equipment and locomotives, the technology and infrastructure to switch to electrification is years or even decades away. As emissions standards tighten and corporations increase pledges to reduce their carbon footprint, fleets require immediate solutions. The clean fuels boom reflects the ability of renewable diesel and biodiesel to reduce a vehicle’s emissions overnight.