March 2023Vol. 31, No. 1

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Biodiesel allows agencies to cut carbon

a biodiesel powered snow plow

Photo: City of Ames, Iowa

New technology is making it possible for transportation agencies to use fuels with higher percentages of biodiesel, even in cold temperatures. In a recent three-year pilot project, the City of Ames, Iowa, used 100 percent biodiesel in heavy-duty snowplow/dump trucks year-round. The results? Better vehicle performance, improved engine lubrication— and much lower carbon-exhaust output.

What is biodiesel?

Biodiesel is a renewable, clean-burning replacement for traditional diesel. “Biodiesels are made from waste fats—anything from used frying oil at a restaurant to waste oils from soybean and corn crops,” says Colin Huwyler, CEO and co-founder of Optimus Technologies. “They are not made from the food portion of these crops. Only material that is not sold to grocery stores and food distributors is used.”


Biodiesel blends are designated by the volume percentage of biodiesel in them. Biodiesel can be used in existing diesel engines in a blend of up to 20 percent (B20) without engine modification.

In very cold weather, biodiesel can gel (freeze) at temperatures higher than conventional diesel does. The higher the biodiesel percentage, the higher the gel-point temperature—a barrier to wider use in winter.

French fries on a table

Photo: Adobe Stock

Biodiesel can also be made in pure 100 percent (B100) form with modifications, preventing gel-point issues.

Ames pilot project

In early 2019, the Ames City Council launched its EcoSmart initiative, which called for city staff to find ways to make the community more sustainable. One action was to ask the Fleet Services department to reduce its carbon footprint. Since 1997, the city’s diesel trucks had been burning B20 blended with 80 percent ultra-low sulfur diesel (#2) during the warm months and a 5 percent bioblend (B5) in the winter.

Ames-based Renewable Energy Group and Optimus Technologies (Pittsburgh, PA) presented a proposal for a B100 pilot program. Staff from the city’s Fleet Services and Public Works departments researched the proposal and found it to be feasible and beneficial for the city’s sustainability goals.

“The effect-to-cost ratio was key to making data-driven decisions on where to invest time and money,” says Rich Iverson, fleet director with the City of Ames. “After looking at options such as electric, which would cost almost a million dollars for one vehicle, the fleet division decided to try the Optimus Vector System.”

The Vector System is an advanced fuel-system technology that enables diesel engines to operate on 100 percent biodiesel. “The system heats the fuel to the optimal temperature before the truck starts running to prevent gelling problems,” Huwyler explains. “It’s a bolt-on technology that can be installed in as few as 12 hours.”

The city council approved five trucks to start. Optimus installed the Vector System on existing vehicles and trained city fleet technicians for future installation and maintenance work. A 12,000-gallon B100 fueling tank also was placed on city property.

The pilot started operation on January 17, 2020, and began collecting real-time data about fuel usage, system performance, and vehicle location. In late 2020, the city added seven more Vector-System-equipped vehicles.

Results: lower carbs, less gelling

The Vector System prevented gelling of the B100 in the colder Iowa winters, and no performance issues were recorded as a fault of the system.

“The reliability of the system has been very good,” Iverson says. “We barely had to spend any time training anyone to do anything—they are just able to go out and do their work. We can spend a reasonable amount of money to burn B100 and get incredible results right now.”

Cumulatively, the city started with 5 trucks and built up to over 14 vehicles using B100 or a B20 blend. In total, around 45,000 gallons of biodiesel were used, reducing carbon by 444 metric tons. The 12,000-gallon tank allowed the city to offset an additional 2,000 gallons of petroleum diesel in other Ames equipment.

The pilot ended on January 17, 2023, and the city looks to add more B100 vehicles to its fleet.

“The city demonstrated leadership in the sustainability space by acting today to reduce its carbon emissions,” Huwyler says.”

—Pamela Snopl, LTAP senior editor

Biodiesel basics

Biodiesel reduces soot/nitration levels
Biodiesel reduces the formation of particulate matter—soot—during combustion by an average of 50 percent compared to petroleum diesel. High soot levels can increase fuel consumption.

Inefficient exhaust is one of the causes of nitration, which occurs when oil becomes saturated with nitrogen-oxide compounds. Nitration can prematurely thicken engine oil. Lower soot/nitration levels reduce wear-and-tear and improve engine longevity.

Health benefits
Whether from school buses or garbage trucks, diesel emissions are prevalent in our communities, exposing drivers and bystanders. Switching to B100 holds promise for improving human health. According to a study published by Trinity Consultants in 2022, the benefits of using B100 include decreased cancer risk, fewer premature deaths, reduced asthma attacks, and fewer lost workdays.

Local economic benefits
Being able to source raw materials from local farmers encourages economic growth in local communities. Other fuel options—such as electric batteries—require overseas imports, which increases carbon emissions for the entire product life cycle. Local production also encourages energy independence, reducing the need for foreign oil imports.

According to the US Department of Energy’s Alternative Fuels Data Center, alternative fuel prices can fluctuate based on location, time of year, and political climate. The center’s Alternative Fuel Price Report provides regional alternative and conventional fuel prices for biodiesel, diesel, and other fuels. The center website notes that the report is a snapshot in time of retail fuel prices, and alternative fuel fleets can obtain significantly lower fuel prices than those reported by entering into contracts directly with local fuel suppliers.

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