How biodiesel is made at Rothsay

Your fats and used cooking oils can be tomorrow's resources. 

At Rothsay, we don’t just manage your used oil, fats and meat by-products – we repurpose them, creating valuable new resources that contribute to a more sustainable world. We process the organic meat by-products and used cooking oils we collect into biodiesel and renewable diesel, as well as nutritional ingredients for livestock feed and pet food. Our company's innovative efforts in biofuel production has helped us lead our industry's growth and development in this area, as well as assisted our customers around the world in reaching their own sustainability goals.

Domestic biofuel production provides jobs and reduces fuel imports

Anticipating a rising need for sustainable fuel solutions among the world’s growing population, Darling Ingredients pioneered the commercial production of biodiesel utilizing recycled animal fats and used cooking oils.

  • Kentucky biodiesel: Beginning operations in the 1990s, our Butler, KY biodiesel plant, still produces clean, efficient fuel that a meets all ASTM 6751 specifications, and reduces emissions by 80% as compared to petroleum diesel.
  • Quebec biodiesel: We were also the first in Canada to operate a commercial animal fat/used cooking oil biodiesel facility, located in Sainte-Catherine, outside Montreal. Started in 2005, our Canadian Rothsay brand produces approximately 45 million liters of clean-burning biodiesel per year, reducing air emissions by as much as 80% as compared to petroleum diesel.
  • Louisiana renewable diesel: In 2013, with our partner Valero Energy Corp., we constructed our Diamond Green Diesel facility outside of New Orleans. This operation is the largest in North America to produce renewable diesel (or "green diesel") from recycled animal fats, used cooking oils and distiller oils. Renewable diesel, unlike biodiesel, is produced in a way that yields a biofuel chemically identical to petroleum diesel, yet emits up to 85% less greenhouse gases, and can be dropped into the existing pipeline for distribution to diesel retailers. DGD currently produces 275 million gallons of renewable diesel annually, and has approved its plant expansion to 675 million gallons for 2021.

As energy resources decline and demand rises, the opportunity to use our used cooking oils and animal fats as feedstock for renewable energy has become more urgent – and more desirable – than ever. No other company in the world has done as much to elevate the value of our customers’ used cooking oil and animal fats.

When we process the meat by-products we collect from our customers, we contribute to maintaining a healthy environment in three important ways:   

  • We divert carbon- and nitrogen-rich materials away from the soil, surface waters, ground water and the atmosphere through effective recycling; 
  • We transform the carbon and nitrogen we capture into useful products, which reduces the production of greenhouse gases that result when new products are produced and later discarded.
  • We offer a safer and more efficient alternative to landfill, incineration or composting of inedible meat by-products or mortalities.