Like many other public and private organizations, school districts are facing growing demands to operate in a more environmentally friendly way.
School bus fleets can play a big role in helping to meet sustainability goals by reducing their emissions —and the fuel used to run buses makes a big difference.
A clean fuel that has generated a lot of interest among fleets of all types, including buses, is biodiesel. It works in existing diesel engines with no modifications required, is affordable and significantly reduces greenhouse gas emissions compared with petroleum diesel and some alternative fuels.
To help you decide if biodiesel is right for your fleet, here’s a cheat sheet to the fuel.
What is biodiesel?
Biodiesel is a cleaner-burning, drop-in replacement to petroleum diesel. It is renewable and biodegradable.
What is biodiesel made from?
Biodiesel is primarily produced from used cooking oil, waste animal fats and vegetable oils. Skilled producers can create high-quality biodiesel that meets customer specifications from a variety of feedstocks, something that’s known as feedstock flexibility.
How can things like canola oil and beef tallow be turned into fuel?
Keeping it to a high-level explanation, biodiesel is made through a chemical process called transesterification in which those oils or fats are converted to what are known as fatty acid methyl esters (FAME), which is the chemical name for biodiesel. Biodiesel has ASTM standards that ensure quality. B20 has a nearly identical ASTM specification to No. 2 ULSD, for example.
B20? What’s that?
The amount of biodiesel mixed into petroleum is the product’s blend level. This is commonly abbreviated to “B” and then that number. B20 is 20% biodiesel and 80% petroleum diesel, for example. B10 contains 10% biodiesel.
What are biodiesel’s emissions characteristics?
Compared with petroleum diesel, a B20 blend has been shown to reduce particulate matter by over 10%, carbon monoxide emissions by over 10% and unburned hydrocarbons by over 20%.
Another interesting way to look at it is how much higher greenhouse gas emissions are for other fuel choices compared to REG B100 (100% biodiesel):
- 580% higher with petroleum diesel
- 435% higher with compressed natural gas
- 195% higher with an electric vehicle with natural gas-derived electricity
- 550% higher with an electric vehicle with coal-derived electricity
How does biodiesel perform in diesel vehicles?
The fact that fleets throughout North America and worldwide use biodiesel blends shows that it meets their performance standards. In some areas, biodiesel actually outperforms petroleum diesel. For instance, the ASTM specification for biodiesel requires a minimum Cetane number of 47, compared with 40 for diesel. Higher Cetane equals a shorter ignition time and better performance. Also, the removal of sulfur in ULSD took the lubricity out of the fuel. A B2 blend can double the amount of lubricity in the fuel. Modern diesel engines rely, in part, on fuel to aid in the lubricating process.
Go inside a diesel engine in this video to see how biodiesel performs.
How popular is biodiesel?
U.S. biodiesel consumption rose 597% from the start of 2010 through 2019.
How can you add biodiesel to your operation?
Fleet operators who want to start using B20 can just pump it into their diesel vehicles and hit the road. Biodiesel blends don’t require any vehicle upgrades. For fleets that operate their own fueling sites, biodiesel is also an easy switch from a supply and infrastructure standpoint.
 REG calculations based on REG biodiesel produced from used cooking oil and based on the CA-GREET model.