Illustration by Gwen Jamison Vogel
Turning waste fat into fuel in Whallonsburg
Farmer Dillon Klepetar scratched his head through a wool cap, holding an oversized wrench in his other hand. He’d been retrofitting the farm’s tractor to run on diesel produced from pig and beef fat, making it the only one of its kind for miles. Although the ability to generate biodiesel from soybean and canola feedstocks is well established, fuel refined from animal fat is still relatively rare.
Thirty-five-year-old Klepetar owns Farmstead Catering at Echo Farm, in Whallonsburg, which caters weddings and other special events from the output of its 170 acres. The pastoral landscape is a juxtaposition of old and new. A milking barn made of hand-hewn beams sits on an aging stone foundation adjacent to plastic greenhouses equipped with modern irrigation. A small staff of young adults busy themselves milking cows while listening to podcasts on Bluetooth speakers. There’s Wi-Fi in every building, solar panels on roofs.
Klepetar’s team started the farm and catering company with very few resources—but, he thought, why stop there? What do entrepreneurial farmers do after perfecting herbed gnocchi and homemade pâté? Echo Farm’s livestock operation creates an abundance of fat, more than can reasonably be processed into lard, candles or soap. Why not try making diesel?
In today’s economy, off-road diesel is cheap, thanks in part to fossil fuel subsidies—our tax dollars—and a domestic glut of oil (although the price is on the rise). Both on-road and off-road diesel fuels hover around three dollars per gallon, a sticker price that doesn’t provide much incentive for the average consumer to change the status quo. But Klepetar is different, wanting to focus on closed-loop farming—a system that recycles its resources. In other words, outputs become inputs. Klepetar and a team of researchers at Cornell University were able to estimate that the true cost of his biodiesel is about $4.50 a gallon. More than a gallon at the pump, but less than the true cost of a gallon of petroleum.
A major portion of a fuel’s total carbon emissions, known as Carbon Intensity (CI), comes not just from burning the fuel but from producing it; from the oil well, through the refinery to the gas stations in our communities. Echo Farm uses solar instead of grid electricity for the fuel refining process. After Cornell University engineers studied the project’s carbon intensity, they found Klepetar’s venture decreased the emissions of production to 3.20 grams of CO2/megajoule. Data associated with fossil fuel diesel vary, but numbers from the state of California put it at 25.6 grams of CO2/megajoule.
“Farms produce a lot of pollution,” Klepetar said. “The oil we burn in our machines to grow food is a mortgage on our ability to do so in the future. Climate change will make everything that is already challenging about farming even more difficult.”
With help from chemical and environmental engineers at Cornell and funding from the New York State Energy Research and Development Authority as well as the US Department of Agriculture, Klepetar started his biodiesel project in 2018. Within nine months, custom agitation and rendering equipment was delivered to Echo Farm—some of which was manufactured by a small Indiana machine shop that makes equipment for the soap industry. Klepetar installed the necessary electrical, ventilation and drainage systems in the farm’s garage.
Over the next several weeks, chunks of animal fat arrived in 55-gallon drums from the butcher and neighboring farms. The chunks are shoveled into a grinder, then a rendering kettle, before undergoing a process called transesterification, which uses catalysts to create a chemical reaction. The resulting micro-refinery is capable of producing up to 120 gallons of diesel every week.
So how much pork fat makes a gallon of diesel? Until his first batch, Klepetar didn’t know. After some experimentation, he found that roughly nine pounds of waste fat make one gallon of diesel. Klepetar’s first batch had about 12 hogs’ worth of leftover animal fat. He thought he might run low, so he incorporated trimmings from two cows that had to be culled. The whole batch of fat totaled 450 pounds, yielding 42 gallons of fuel.
Borrowing technologies from the marine, auto-racing and hydraulics industries, Klepetar and a local mechanic made modifications to his tractor so it would run on unblended biodiesel. A dash switch and a second fuel tank were installed so the machine can start and stop on petro-diesel in winter, to prevent the biodiesel from turning to Jell-O in the lines.
The next step will be growing the movement. Klepetar has already established partnerships with 12 local farms and he’s dedicated to sharing his knowledge. “I want everything I’ve learned to be published online and free to anyone to replicate,” he said. Cornell’s Small Farms Program has committed to getting the word out and using this project as an open-source engineering model to be adopted statewide.
Finally the day came to fire up the tractor for the first time, its auxiliary tank full of renewable energy. Several farmers and friends stood in the field to watch. “First run’s for Ruby!” Klepetar said, a one-line eulogy to his favorite dairy cow, whose remnants now sloshed in the tank.
With the motor running on petroleum, he flipped the switch. The auxiliary fuel pump activated and the exhaust roared—clean-burning and emitting a pleasant, mild odor. Cheering let loose from the crowd. A pair of dogs started to bark, unsure of what had just happened. Only when Klepetar shut the tractor off prematurely did the fuel lines gum up in the cool March air. A little while later, and a few adjustments with a wrench, Ruby was again coursing through the motor. She was about to take Klepetar around the field for the next several hours, the same pasture she once grazed.
