Biodiesel and the X15: Low-carbon power for 2027 and beyond

For nearly 20 years, biodiesel has been approved by Cummins for use in its on-highway diesel engines.

Cummins’ iconic workhorse, the X15 diesel, is approved to run up to B20 which contains up to 20% biodiesel mostly obtained from soybeans. 

Fleets and owner-operators using biodiesel in the X15 have long-enjoyed greater lubricity, lower emissions and higher cetane values over conventional diesel. 

A low carbon fuel like biodiesel will get even better when paired with Cummins’ new 2027 X15.

“I'm excited now more than ever to hear and get feedback from the industry,” Clean Fuels Alliance America Technical Director Scott Fenwick said of the latest advanced diesel engines like the Cummins 2027 X15 which meet EPA 2027 emissions regulations. 

Fenwick noted that companies remain dedicated to lowering their emissions regardless of regulatory direction. Pepsi and ADM recently announced their commitment to testing B99 supplied by Pilot, the first station in the U.S. to provide nearly pure biodiesel. Trucks will be equipped with Optimus fuel systems that enable B100 use. 

Clean Fuels Alliance America has been working alongside Cummins and other OEMs for several years to increase the quality and availability of biodiesel. The Department of Energy currently lists 1,663 public and private fuel stations in the U.S. that supply B20. 

“Cummins in running some field trials using biodiesel blends greater than B20,” said Jeff Klopfenstein Liquid Fuels expert at Cummins Corporate R&T Chemical Technology Group. “That’s going to accelerate soon because companies want to decarbonize."

“More and more, we're seeing a customer choice for low carbon fuels, for renewable fuels,” Fenwick said. “Even though regulations around the world are being rolled back they still want to reduce their carbon footprint. They’re going to proactively choose low carbon renewable fuels. It's an exciting time.” 

Steve Howell, longtime chair of the American Society for Testing and Materials (ASTM) Biodiesel Task Force and co-founder of MARC-IV Consulting, has also worked alongside Cummins for years researching and steadily improving biodiesel performance. The veteran oil chemist also sees corporate carbon goals creating more interest in biodiesel particularly as electric truck mandates are sidelined by state and federal lawmakers.  

“We see that as the major driver moving forward,” Howell said. “And we see biodiesel in new diesel technology being a real winner there and renewable diesel as well because the new 2027 engine technology has tailpipe NOx emissions at almost a near-zero level.” 

Both Howell and Fenwick credit Cummins for its ongoing work in testing biodiesel both in the field and in the lab. Cummins first approved biodiesel use in 2007. 

“Over the years, Cummins has worked positively and cooperatively with the industry to provide a bunch of the data needed to help set the specs and then to basically identify the performance characteristics of biodiesel,” Howell said. 

“Cummins has been fantastic to work with,” Fenwick added. 

Stay tuned as Tom explores how biodiesel continues to evolve—next up, a closer look at the testing and specifications driving its performance gains.