A Deep Dive Into Renewable Diesel

The shift to cleaner, sustainable fuel alternatives has become more critical than ever as countries and industries work to combat climate change. Broader adoption of renewable diesel is a key part of Cummins Inc.’s effort to provide customers with the widest range of lower-carbon fuel alternatives for their powertrains through our Destination Zero strategy.

Let’s dive into what renewable diesel is, how it’s made, its benefits and compatibility with Cummins engines, all while highlighting its role in making the transportation sector more sustainable.

What is renewable diesel and how is it made?

Renewable diesel, also known as R100 or Hydrotreated Vegetable Oil (HVO), is a drop-in replacement for diesel. It represents a significant advancement in sustainable fuel technology. Renewable diesel is produced from recycled vegetable oils, tallow or used cooking oil.

HVO is processed using hydrogenation to create a cleaner burning alternative to traditional diesel that works in existing engines. Hydrotreating reacts fats, oils and greases (common feedstocks) with hydrogen under high pressure and temperature in the presence of a catalyst to create renewable diesel. This process creates a high-quality fuel that is chemically similar to traditional diesel but with a much lower carbon footprint.

Renewable diesel differs from biodiesel in its production process and physical properties. Biodiesel can also be blended with traditional diesel derived from fossil fuels. In contrast, renewable diesel can be used as a drop-in replacement for traditional diesel without the need for blending.

How much renewable diesel is out there?

The availability of renewable diesel is increasing as demand grows. Currently, there are 16 plants producing renewable diesel in the U.S., with a total capacity of 2.8 billion gallons per year. Although it may seem like a lot, compared to overall diesel use, it’s a small quantity. 122 million gallons of diesel are used per day in the U.S. alone. The U.S. Energy Information Administration (EIA) projects that U.S. renewable diesel production capacity could reach 384,000 bpd, or 5.9 billion gallons per year, by the end of 2025.[1]

This surge has been driven by the growing recognition of renewable diesel's environmental benefits and its ability to be a drop-in fuel in diesel engines. As transportation fleets intensify their efforts to reduce carbon emissions, renewable diesel is poised to play a key role. Its increasing availability is a positive sign for fleet operators looking to switch to more sustainable fuel options.

Can I use renewable diesel for my truck?

Various models of Cummins’ vehicle engines and power generators are designed to accommodate the use of R100 without requiring any modifications, making the transition to renewable diesel seamless for fleet operators. Cummins has approved up to 100% blend of paraffinic fuels for B6.7, L9, X12*, X15* On-Highway engine series. Cummins HELM™ platforms and advanced diesel engines are also supporting customers in their journey to lower emissions through renewable diesel compatibility.

*While running with Paraffinic Fuel, check or reset valve lash at half the specified service interval. Refer to the owner’s manual. X15 CM2350 X130C must be built or have an ECM calibration code released after November 9, 2022. X15 CM2350 X140C must be built or have an ECM calibration code released after December 19, 2022.

How can renewable diesel decarbonize your fleet operations?

Customers who adopt renewable diesel like R100 can significantly contribute to achieving their sustainability goals and overall operations. Using renewable diesel reduces greenhouse gases (GHG) by up to 90% of CO2, NOx and particulate matter (PM).

This dramatic decrease is primarily due to the lifecycle carbon intensity of renewable diesel, which is significantly lower. For fleet operators looking to decarbonize their operations and contribute to a more sustainable future, switching to renewable diesel presents a viable and impactful solution.

Key benefits of renewable diesel

While renewable diesel fuel has similar chemical and physical properties to diesel fuel, its fossil-free composition and low carbon content make it an appealing sustainable fuel option. Beyond environmental benefits, renewable diesel offers several advantages for fleet operations.

One key benefit is improved engine performance because of more efficient combustion. Renewable diesel has a higher cetane number than conventional diesel, meaning it combusts faster when the engine is started.

Cetane number is a measure of fuel quality. It indicates how well the fuel will burn within the engine cylinder. The higher the cetane number, the shorter the ignition time, meaning the better the combustion. The scale for measuring cetane ranges from 0-100. Renewable diesel has a cetane number between 75 and 90, compared to petroleum diesel which ranges between 40 and 45.

HVO also has approximately 7% less fuel density and limited aromatic and sulfur content. With its nearly zero sulfur content, HVO helps avoid deposit buildup in engine exhaust aftertreatment systems, promoting cleaner combustion that cuts down on maintenance and, therefore, overall operational costs.

Renewable diesel’s high lubricity is a significant benefit as well. It reduces the friction in the engine’s fuel pump and injectors. Smooth engine operations are ensured with higher lubricity, enhancing the engine's life and yielding a greater return on investment for customers throughout the vehicle’s lifespan.

Typically, renewable diesel can run in cold temperatures. Renewable diesel maintains its fluidity in cold weather, ensuring consistent performance and reliability. This robustness is particularly beneficial for fleets operating in regions with freezing climates, as it negates the need for additives or special handling procedures that are often required to prevent diesel from gelling.

Furthermore, storing and handling renewable diesel does not require any special infrastructure changes at the fleet’s facility. It can be stored in existing diesel tanks without the risk of contamination or degradation, providing an ease of transition for fleet operators switching from traditional diesel. This interchangeability extends to fueling infrastructure as well, which means that renewable diesel can be pumped through existing diesel fuel dispensers without the need for costly upgrades or modifications.

As the transportation industry works towards decarbonization, renewable diesel stands out as a practical, efficient and sustainable solution. Cummins is constantly working and innovating to bring the most sustainable transportation solutions to customers across the world.