How to turn leftover oat waste into renewable electricity

(in New Jersey)

“It’s a bit gross.”

Those are the words you might hear from Oatly employees when they’re asked to describe the brown gloop of oats, water, and fiber that remains after oats are turned into Oatly-like things. And while “gross” is not a description a food manufacturer wants to hear, it’s admittedly pretty accurate. Anyway, the reason we need to talk about oat residue is because we have a lot of it, and we need to find sustainable uses for our leftovers.

The good news is that at our plant in Millville, New Jersey, we’ve uncovered one such use: turning oat residue into renewable electricity. With the help of our friendly neighbors at Trenton Renewables, we can transform some of our residue while also sourcing 100 percent renewable electricity to power our factory and charge our fleet of electric trucks.

Intrigued to see this most likely unappetizing magic in action, we went to Millville, and here’s what we found.


Welcome to Millville, New Jersey, one of the state’s largest oat-drink factories. Also potentially the state’s only oat-drink factory.

We (as a humble Oatly copywriter) have no idea what these tanks and towers are for, but they presumably help us make Oatly

Step 2:

This is Whistle. He’s loading a steady stream of the delicious oat residue we’ve been talking about into a tank to be delivered to our partners at Trenton Renewables. We did tell you it wasn’t appetizing…

A hand playing with oat residue from a pipe.

Whistle doesn’t typically play with the gloop in his hands, but he’s putting on a little show for us. Thank you, Whistle.


Can we just pause for a moment and appreciate that we work with a person named Whistle?
Okay, where were we…


When the tank is full, it’s taken to Trenton Renewables, whose general mission is to “use biology to turn waste into energy,” which seems sensible.  

Along with other organic materials, our oat residue is dumped into a machine we like to call the biodigester, mostly because that’s what other people call it.


There’s not much to look at here. This oat residue concoction is being ground up and monitored to ensure the right combination of nutrients are present to make compost and biogas. 

Oat residue concoction being monitored on a CCTV


Remember the biogas we mentioned just a sentence ago? That biogas is used as fuel to generate renewable electricity


In 2021, Oatly purchased the equivalent amount of Renewable Energy Certificates (or, if you’re in a hurry, RECs) from Trenton Renewables to match 100 percent of the electricity used at our Millville factory, creating a less wasteful, more sustainable production process

Great job, everyone- here’s to turning brown oat gloop green!