Like any department within a company, fleets are constantly looking for ways to cut costs. Add the need to cut vehicle emissions as well, and you have an issue compounded by reduced budgets. For most fleets, the current and upcoming increased fuel economy standards can affect fleet budgets considerably, which is why renewable resources, such as renewable diesel, are a simple first step in meeting their goals.
For starters, information on the difference between renewable diesel and diesel can go a long way in increasing understanding and acceptance. Renewable diesel, in some forms, is known as hydrogenation-derived renewable diesel (HDRD), which is processed waste fat or vegetable oil. It is produced 100% from renewable raw materials and can reduce greenhouse gas emissions by 80%.
Renewable diesel is processed in a similar way to petroleum diesel and fleets have seen a number of benefits from its use. Since it’s hydrogenated, renewable diesel isn’t affected by freezing temperature and storage. During hydrogenation, hydrogen replaces other atoms such as sulfur, oxygen and nitrogen and converts the oil’s triglyceride molecules into paraffinic hydrocarbons. The similarity in chemical structure also allows renewable diesel to be used in engines that are designed to run on conventional diesel fuel. The high cetane number of renewable diesel, which is around 75-85, ensures clean and efficient combustion resulting in greater engine performance and fewer harmful emissions.
Engine manufacturers have taken notice and are increasingly approving the use of renewable diesel in their engines. Cummins recently certified its use in its B4.5, B6.7, and L9 medium-duty engine platforms, after holding an 18-month field test. Its engines were tested with 100% renewable diesel fuels in order to study the effects of the fuel on engine performance, aftertreatment and fuel system durability. Cummins is now testing the possibility of using the fuel with its other light-duty, heavy-duty and high-horsepower engines. Mack Trucks and Volvo Trucks have also approved the use of renewable diesel fuel in all its engines after performing road and lab testing.
Many fleets are also seeing the possibilities, including giants like UPS. Last summer, the company signed agreements with three suppliers for up to 46 million gallons of renewable diesel over the next three years as part of its goal to significantly reduce emissions by 2020. In the next three years, UPS will attempt to replace 12 percent of conventional fuels in its fleet of trucks. The plan also includes using the fuel outside the U.S.
City and county officials in California are taking the route towards renewable fuels. Sacramento County currently uses renewable diesel in many of its heavy-duty vehicles. More than 400 municipal public works trucks and specialty vehicles have made the switch, which the county expects to yield greenhouse gas emissions reductions of up to 80% - an estimated 8,000 tons per year. The City of Oakland’s fleet of 250 diesel-powered vehicles and equipment has been running on renewable diesel since 2015, using approximately 230,000 gallons annually. That same year, both the City of San Francisco and the City of Walnut Creek made the move to renewable diesel.