Alameda and San Joaquin Counties in California have both begun using renewable diesel to fuel their fleets.

Alameda County Transportation Services Manager Doug Bond said that the county has been running electric or hybrid electric vehicles since the late-1990s. Most recently, the county was using B-20 biodiesel to fuel some of its fleet. Alameda County purchases about a million gallons of fuel per year, and about 10% of that is biodiesel. 

"We’ve been trying alternatives for years,” Bond said. "Basically we’ve been looking to displace petroleum use and anything that comes from oil and trying to move away from it."

Alameda County made the switch to renewable diesel about a month ago, and the program has already yielded results. Bond has seen reductions in NOx emissions and particulate matter as well as a gain in fuel efficiency. The department has also saves of about 9-10 cents per gallon compared to biodiesel. 

"There are no ill effects to it; there are huge reductions in emissions," Bond said. "It’s really an easy choice and it’s less expensive than what we were paying on the B-20 before."

San Joaquin County began considering renewable diesel last September. Fleet Manager Kevin Myose saw a presentation about renewable diesel at a Municipal Equipment Maintenance Association meeting and was interested in the environmental advantages.

"In San Joaquin County, the air basin has some of the dirtiest air in the nation," he said. "We’re always looking for ways to reduce our output."

Over the years, San Joaquin County considered a number of alternative fuel options, but had issues with many of them. One selling point of renewable diesel was that it worked within the county's existing infrastructure and did not require any additional equipment, as compressed natural gas (CNG) would.

"The way our fleet’s structured, we don’t have a lot of applications that can really leverage CNG very well," Myose said. "There are some other issues with biodiesel. It causes swelling of seals and some other issues in the equipment itself."

The county finally purchased its first tank in March with no complaints so far. Switching over saved San Joaquin County about $2,000 but, more importantly, has helped make the air quality cleaner and has even helped the department cut down on maintenance.

"It’s estimated about 60-90% reduction in CO2 just from switching to the fuel. There’s about a 33% reduction of particulate matter, specifically PM 2.5, which is known to be a health hazard. It’s one of the main causes of respiratory problems," Myose said. "I think what we’re gonna see, and what other jurisdictions have seen, with the particulate trap is that you have more time until it needs maintenance again. There's less particulates that it’s trapping because there is less particulates in the fuel."

Myose also said that renewable diesel's chemical makeup resembles a premium diesel, with its lower cloud point and higher cetane rating.

"It’ll work in colder weather and it has more energy per molecule," he said. "There are a lot of benefits in that." 

Both fleet managers highly recommend the switch to renewable diesel.

A number of West Coast fleets have made the switch to renewable diesel over the past few years, including Carlsbad,Long Beach, and San Francisco in California and Corvallis and Eugene in Oregon.