Selecting the Fuel that Makes Cents for You: Renewable Diesel

April 30, 2021

renewablediesel-vs-diesel — Renewable diesel (left) burns cleaner than traditional diesel. (Image courtesy of Neste)

Editor’s Note: This article is the third of a three-part series focusing on alternative fuel options for school districts.

Not to be confused with biodiesel and despite their similarities, renewable diesel reduces emissions, delivers a strong performance, and contains up to 85 percent less sulfur than ultra-low sulfur diesel.

While renewable diesel is one of the newer alternative fuels on the market, it is quickly becoming more popular and accessible in all states. Still, relatively few school districts are utilizing renewable diesel, despite it being considered a drop-in fuel that requires no additional infrastructure or engine tuning.

Chris Ellison has had great success utilizing it at his Oregon school district. Prior to being named the transportation manager at David Douglas School District near Portland, Ellison was the transportation manager at Eugene School District, where he introduced renewable diesel to school buses.

During his tenure at Eugene, Ellison operated a total of 122 buses, 107 of which ran on R99, meaning the fuel is made from 99 percent renewable resources. Another 10 buses ran on propane, and five on gasoline. Ellison said during the virtual Green Bus Summit on April 21 that while David Douglas isn’t currently operating R99, he is in the process of procuring it.

When comparing biodiesel and renewable diesel, the fuels can be made from the same feedstocks, offer lower carbon emissions, and can be used in existing diesel equipment. However, with renewable diesel, the feedstock reacts with hydrogen during a process called hydrotreating, which removes all oxygen. Biodiesel, on the other hand, goes through a process called transesterification, in which oxygen remains. Ellison explained when oxygen is introduced into fuel, bacteria and other organisms can grow. The result can be clogged u fuel lines and filters.

Another main difference between the two fuels is that the main ingredient of renewable diesel is palm oil, which is grown in tropical climates, Ellison added.

He explained when he first started using renewable diesel at Eugene Public Schools, the price was around $0.50 more per gallon than regular diesel. However, when he left Eugene, it was down to about $0.20 more per gallon.

He noted that renewable diesel has the same operating characteristics as diesel, but it performs better in colder weather. He added that gelling in colder temperatures can occur with biodiesel, leading to vehicles not starting in the morning. But he said he has not experienced that with R99.

When first installing R99 into his two 20,000-gallon underground fuel tanks, there was concern the fuel might seep through the gasket, as that had been a characteristic of synthetic oil. However, Ellison said the district experienced no seepage. Renewable diesel is also stackable, meaning if there is a supply issue, which there has been, Ellison can revert to using B5 fuel, and add it to the remaining R99 fuel in the tank without noticing any operational differences.

In reference to the supply shortage Ellison explained that because renewable diesel is produced and imported from other countries, such as South or Central America, there is sometimes a delay in shipment.

Neste, one of the world’s largest producers of renewable diesel and renewable jet fuels, has distributors and headquarters in the U.S. However, according to its website, it currently manufactures the product at factories in Finland, the Netherlands, and Singapore. Theodore Rolfvondenbaumen, the communications manager for Neste North America, told School Transportation News that while there is no production in the U.S., the company is growing rapidly within the county.

“Across the country, Neste is hiring more people, expanding our supply chain infrastructure, and collecting more locally sourced used cooking oil to turn into renewable fuels,” Rolfvondenbaumen said. “For example, in the U.S. West Coast, we are expanding our network of renewable diesel fueling stations, creating a renewable fuel hub, and partnering with local companies to distribute renewable diesel to customers. Nearly 30 percent of Neste’s total volume of renewable diesel, about 1 billion gallons per year and growing, comes into the US.”

He added that by investing locally, Neste is making it easier for any city, business, or school district to access its renewable diesel. He advised school districts interested in renewable diesel to access the distributors and fueling stations via its website.

Meanwhile, Ellison added that one disadvantage that might turn people off from using the fuel is its environmental concern. He said rainforests are being cut down in places like Brazil to plant oil palm trees, from which renewable diesel is made.

But Renewable diesel can reduce the number of parked regens, which Ellison said results in huge savings, as a bus doesn’t have to sit outside the shop at a high idle and use more fuel to reach the necessary engine temperature to burn excess soot. He added that in the past three and half years of using R99 at Eugene, he had no parked regens and very little on-the-road regens. This, Ellison said, adds up to less downtime.

Less downtime is also one of the biggest advantages for drivers, Ellison said. He noted that drivers have expressed their school buses spend less time in the shop, and the vehicles run smoother. He said technicians are also very supportive of the fuel, as they don’t have to remove the DPF filter and have it parked outside while idling.

Raymond Manalo, fleet director at Twin Rivers Unified School District in Sacramento, California, said his operation has been using renewable diesel for the past two and half years. He came on-screen during the session moderated by consultant Denny Coughlin, a retired fleet manager for Minneapolis Public Schools and owner of School Bus Training Company, to discuss his experience. Manalo said he, too, has noticed that renewable diesel results in a drop in active and passive regens.

Ellison concluded that Cummins has approved the fuel for use in its engines, and he wants to see renewable diesel become more widely used.