As governments work toward lowering emissions and reducing the carbon footprint of the
Biodiesel offers a means of lowering emissions and reducing the use of traditional petroleum diesel
machines that drive our industries, new technologies and techniques arise every day to meet those standards.
Diesel, in particular, is both one of the most common fuels in heavy equipment-related industries and among the most common targets for attempts to reduce emissions. One interesting way to address the latter while still using diesel is to substitute biodiesel. To that end, members of the National Biodiesel Board, or NBB, are looking to drastically increase the biodiesel usage in commercial vehicles in the coming years.
Biodiesel is a clean, renewable and domestically produced fuel consisting of mono-alkyl esters of long chain fatty acids derived from vegetable oils or animal fats. Biodiesel is blended with petroleum-based diesel and designated with BXX, where the XX represents the volume percent of biodiesel included. (For example, a blend with 20 percent biodiesel would be designated B20.)
“Biodiesel uses a simple low-pressure, low-temperature reaction with methanol in a process called transesterification that changes the oil/fat as little as possible in order to make a diesel fuel that works well in an existing diesel engine,” said Steve Howell, senior technical advisor with the NBB. “Biodiesel does not remove the oxygen from natural oils/fats, and the oxygen in biodiesel provides superior lubricity, biodegradability, and provides lower emissions of particulates, unburned hydrocarbons and carbon monoxide than are possible with hydrocarbons alone.”
B20 needs no retrofitting
For a fleet operator, the greatest benefit of biodiesel might be the ability to use B20 and lower blends in diesel engines without modification — B20 is supported by most original equipment manufacturers. This option negates the need to retrofit an entire fleet or purchase new fuel vehicles in order to switch to biodiesel. B20 blends are also cost competitive and can be easily adopted into existing fueling infrastructure.
“Biodiesel also offers the easiest way to green your fleet operations,” said Jennifer Weaver, the NBB’s OEM market development manager, in advance of a panel presentation on biodiesel and renewable diesel scheduled for the 2018 Work Truck Show in Indianapolis this March. “Since biodiesel is made from renewable oils/fats that are a minor by-product of producing protein, biodiesel provides an 80 percent life cycle carbon reduction compared to petrodiesel, with B20 providing a 16 percent carbon reduction. Sunlight and carbon dioxide from the atmosphere help grow the oils/fats for biodiesel — essentially a form of ‘liquid solar energy.’”
Weaver further noted that as a diesel fuel, biodiesel meeting ASTM D6751 specifications has superior cetane and lubricity, is biodegradable and non-toxic, and provides lower emissions of air toxics, particulates, unburned hydrocarbons, and carbon monoxide from engines without new after-treatment technology. (ASTM International is a standards organization originally called the American Society for Testing Materials.)
Biodiesel also works well in new technology diesel engines because particulates created by biodiesel burn off faster and at a lower temperature in a particulate trap than those of petrodiesel.
With those benefits, it’s easy to see why groups like the NBB and others are interested in promoting the use of biodiesel. However, that doesn’t mean that adopting biodiesel is a completely painless process, as Howell noted.
Cold challenges
“With the changes to improve the ASTM specifications over the last 10 years and increased attention to fuel quality through the biodiesel industry’s robust BQ-9000 fuel quality program, the main challenge for users with biodiesel today is cold flow properties,” Howell said. “Since the biodiesel production process does not change the structure of the oil/fat carbon chain, pure biodiesel has a higher cloud point than most petrodiesel. Cold flow has largely been addressed through using B20 or lower blends during colder months, as well as the traditional techniques and housekeeping protocols used to manage cold flow of #2 diesel fuel — such as blending with #1, use of additives, or use of heated fuel systems.”
The goal of the NBB is to achieve 4 billion gallons of fuel sales, largely in B20 and lower blends, by 2022 — the equivalent of roughly 10 percent of the on-road diesel fuel utilized in America today. Since all fossil fuels increase the CO2 in the atmosphere there is a growing interest in lower carbon alternatives including wind and solar for electric and hybrid vehicles and in renewable fuels such as biodiesel and renewable hydrocarbon diesel in conventional engines.
“Despite modest gains by alternative powertrains, commercial movement of goods will continue to primarily rely upon internal combustion engines,” Weaver said. “The turnover in this sector is much slower than in the light duty market and the requirements to move heavy loads over long distances largely dictate what fuels and powertrains are being leveraged. And in the vast majority of cases in the commercial sector, the powertrains of choice are the powerful, durable, high-fuel-economy diesel or hybrid diesel engines.”
Diesel remains popular
The adoption of alternative powertrains will have an impact, but there will likely continue to be a need for products and devices that work with conventional diesel powertrains. Research commissioned by the Fuels Institute in 2016 indicates that by 2025 the vast majority of registered commercial vehicles — 61.86 percent — will still have diesel powertrains that can be powered by renewable biodiesel blends.
The fuels and powertrain technologies that are used in the future will be determined by a variety of factors. State and federal regulations on carbon reductions, what incentives may be put in place to drive those changes, what customers and the general public need from their vehicles, and what they are willing to buy will all affect the speed of the transition to alternative fuels and powertrains.
“The future of the fuels market is heavily influenced by the vehicle market and vice-versa — the two are inseparable,” Weaver says. “As automakers seek to comply with increasingly stringent requirements for vehicle performance and efficiency, the impact on power train diversity and fuel preference could be significant.”
— Matt Jones
Matt Jones is a freelance writer based in Fredericton, N.B.
