As gas prices skyrocket, this Sonoma Valley High grad doubles down on biodiesel

Walking to his biofuel-powered 1981 Mercedes 300SD Turbo Diesel equipped with dual 20-gallon gas tanks, Joseph Silvi says the one downside of using alternative fuel is the smell of fried food that stirs up his appetite.

“I rolled up to my friend's house once with it, and they were like, ‘Was that someone cooking?’” Silvi, 19, said. “I'm like, ‘No, that's my car.’ I guess it smells better than just regular diesel fumes.”

Now Sonoma Valley High School’s 2021 valedictorian is a freshman at UC Berkeley, where he enjoys the low cost of biofuel while others pay record-high prices at the pump. Though Silvi’s biofuel gets about the same amount of miles per gallon as diesel, he said, it releases almost 20% less emissions than diesel, according to the Environmental Protection Agency.

His idea was originally birthed after the Silvis’ car battery died at First Baptist Church on First Street East, and a fellow parishioner drove him and his sister home.

“It was a late ‘70s-era diesel Mercedes, so a little bit older than mine,” Silvi said. “And that kind of just spurred an interest in those cars. So I started watching a ton of YouTube videos and that led to all these other videos about people running them on alternative fuels.”

On a brisk Monday morning in Boyes Hot Springs, Silvi’s Mercedes is parked in the driveway next to another project, a home garden, enclosed in light wire. Silvi is wearing a shirt the same color as a wheatgrass shot, dotted with a bright pink polo player. He carefully steps over a rock path to the side of the house where he turns fry oil into fuel.

DIY diesel

Dulce Silvi, Joseph’s mom, said her son has had a longtime fascination with green energy. She recalls him reading about farm vehicles that used biofuels like cooking oil and watching documentaries about cars that ran on alternative fuels in Scandinavia.

“He was a junior when he found this car, and he was really looking for something that ran on diesel,” Dulce Silvi said. “He found this (car) and started making his own biodiesel. I believe it was last year when he finally succeeded with a biodiesel batch that he could put in his car.”

Creating biodiesel was a process of trial and error, Silvi said, adding that cooking oil alone might let his car run but it could create unwanted gunk in the engine.

“I started back in November (2021), but I hadn't really dialed in the chemistry right,” Silvi said. “The first couple of batches did not go well. The first one, especially. It just turned into a big eight-gallon tub of soap.”

Yes, soap.

If cooking oil has too much water in it, Silivi said, the chemical reaction with sodium hydroxide or potassium hydroxide creates industrial soap. But once oil is by isolated and the chemical mix is added, the result is a fatty acid compound that is molecularly similar to diesel.

“And that's running pretty well,” Silvi said. “I have a lot of plans to repair other stuff during the summer, so it's just a constantly evolving project.”

Silvi said he owes a thanks to local restaurants that donate their used kitchen oil to him, including OSO, Picazo Kitchen and Bar, Murphy Irish Pub, Amy’s Peking Palace and the Red Grape.

Ordinarily, these restaurants would employ an oil-removing service like the North Bay Restaurant Services to properly dispose and recycle their cooking oil, but restaurants were happy to hand over the unwanted waste to Silvi.

Biofuel and beyond

As gas and diesel prices have surpassed $6 a gallon at many gas stations, in recent weeks Silvi has told his family: “Just take my car. It doesn’t cost anything.”

He has been thankful for the cheap fuel during his weekend drives home from Berkeley. But the heart of his projects have always been driven on helping others, Dulce Silvi said, and it remains part of his mission as an environmental engineering student.

“He's always been so thoughtful, he loves to help. And that's one of his passions. He just loves to help and loves finding solutions,” Dulce Silvi said. “And we're so grateful that he's on this planet."

The planet might also be thankful for her son, who said he’s always appreciated nature and has been inspired by the environment of Sonoma Valley’s acres of vineyards and hot springs.

“The rate we’re going of our use of resources isn't sustainable,” Silvi said. “Even for people who aren't really concerned about the environment, fossil fuels are just a finite resource. So we have to find alternatives whether or not you care about the earth. And so I think people pioneering development of alternative energy sources is really important.”

Silvi hopes to take his experience of adapting his car for biodiesel and scale it through the Biofuelds Technology Club for all the vehicles on Berkeley’s campus. The university has a goal to be carbon neutral by 2025, and eliminating gas-powered vehicles goes a long way to helping reach that mission, he said.

“My car is the test vehicle currently and then we'll move on to other campus vehicles,” Silvi said. “The Biofuels Technology Club is to start coordinating with the dining halls... to collect their cooking oil.”

Contact Chase Hunter at chase.hunter@sonomanews.com and follow @Chase_HunterB on Twitter.