Protein, pet food, and green fuels: how Darling’s Diamond Green Diesel fits together

Darling’s Diamond Green Diesel turns animal by-products and used cooking oil into renewable diesel at industrial scale. What the joint venture with Valero delivers in volume, feedstock flexibility, and climate impact – and where it fits in Darling’s broader rendering and pet food portfolio.

Edited by ad hoc news Flagship & Bestseller Desk. Reviewed before publication on 06/15/2026 at 5:20 PM ET. Details in the imprint.

Diamond Green Diesel, the flagship renewable diesel venture of Darling Ingredients and Valero Energy, has grown into one of the largest low-carbon fuel platforms in North America by turning animal by-products and used cooking oil into drop-in diesel for trucks, buses, and fleets. The complex now counts three major plants in Louisiana and Texas with a combined nameplate capacity of roughly 1.2 billion gallons of renewable diesel and 470 million gallons of sustainable aviation fuel per year, anchored by the original Norco facility that has been repeatedly expanded since its 2013 start-up. Darling’s own overview of the Diamond Green Diesel platform highlights how the joint venture uses rendered fats, used cooking oil and other waste lipids as feedstock instead of virgin vegetable oils.

What Diamond Green Diesel actually produces – and from what

At its core, Diamond Green Diesel is designed to process waste fats and oils from Darling’s global rendering network into hydrotreated renewable diesel that can be blended with, or fully substitute for, petroleum diesel in existing engines and infrastructure. The joint venture uses a hydrotreating and isomerization process similar to that found in modern oil refineries, but configured to handle animal fat, used cooking oil and distillers corn oil as primary feedstocks, converting the triglycerides into paraffinic hydrocarbons with a very high cetane number and low sulfur content, while co-producing renewable naphtha, liquefied petroleum gas and, at the Port Arthur site, sustainable aviation fuel that meets ASTM jet fuel specifications. According to recent investor materials, Diamond Green Diesel’s three plants together are engineered to handle well over a million metric tons of waste lipids annually, leveraging Darling’s collection of used cooking oil from restaurants and food processors as well as tallow and other animal-derived feedstocks that would otherwise have limited value or end up in lower-grade uses.

The original Diamond Green Diesel plant, located in Norco, Louisiana adjacent to Valero’s St. Charles refinery, started operations in 2013 and has been expanded several times to reach a nameplate capacity in the hundreds of millions of gallons per year, giving the joint venture an early lead in North American renewable diesel production. Subsequent projects in Port Arthur, Texas and an additional train at Norco significantly increased output, with the newer Port Arthur facility designed from the outset to swing between renewable diesel and sustainable aviation fuel as airlines and regulators push for lower life-cycle emissions from jet fuel. The process yields a fuel that is chemically similar enough to petroleum diesel to be used as a “drop-in” product, avoiding the need for new engines or fueling infrastructure and differentiating it from first-generation biodiesel, which typically faces blend limits and cold-weather performance constraints.

Feedstock flexibility is a critical technical and commercial feature of the Diamond Green Diesel model because it allows Darling and Valero to optimize margins by balancing feedstock availability, logistics costs, and policy-driven credit values. With access to Darling’s global network of rendering plants and grease collection routes in North America and parts of Europe, the joint venture can prioritize lower-carbon, lower-cost waste streams such as used cooking oil and animal fats over more expensive refined vegetable oils, which are in demand for both food and energy uses. That capability also positions the platform to respond to evolving sustainability criteria in markets such as California’s Low Carbon Fuel Standard and federal renewable fuel programs, where life-cycle greenhouse gas scores and feedstock categories directly affect the value of the credits generated by each gallon of fuel produced.

From a market perspective, Diamond Green Diesel’s output is aimed primarily at refiners, fuel marketers and large fleets that need low-carbon diesel and aviation fuel but want to avoid engine retrofits or operational complexity. Finished renewable diesel from the Norco and Port Arthur plants can be transported through existing pipelines and terminals or shipped via barge and rail, then sold either as a neat product or blended with petroleum diesel to meet local specifications and customer requirements. This compatibility lowers adoption barriers for trucking, municipal bus operations, and off-road equipment users that are under pressure to cut emissions but cannot easily electrify heavy-duty applications, providing Darling’s fuels segment with a distinct customer base compared to its food and pet food ingredients businesses. At the same time, sustainable aviation fuel produced at Port Arthur targets airlines and corporate travel programs that are increasingly using SAF purchase agreements to meet climate commitments.

The economics of Diamond Green Diesel are tightly linked to public policy, including US renewable fuel standards, the federal blender’s tax credit and state-level programs such as California’s Low Carbon Fuel Standard that reward fuels with lower life-cycle greenhouse gas emissions. Renewable diesel from waste fats and used cooking oil generally receives favorable carbon intensity scores in these systems, which enhances the value of each gallon beyond the underlying diesel replacement and helps offset the capital and operating costs of the hydrotreating facilities. While this reliance on policy support introduces regulatory risk, the joint venture structure with Valero provides access to refining know-how, hydrogen, and logistics infrastructure, while Darling contributes feedstock security and waste collection expertise, creating a vertically integrated chain from slaughterhouses and restaurants to fuel terminals. Industry coverage of the renewable diesel market routinely points to Diamond Green Diesel as one of the largest and most mature platforms in the sector, with capacity and scale that set a benchmark for competitors. Valero’s recent press releases on renewable fuels expansion have repeatedly underscored the role of the joint venture in its broader low-carbon fuels strategy.

Within Darling Ingredients’ overall business, Diamond Green Diesel sits in the “Fuels” segment alongside its other renewable energy operations, complementing the company’s core rendering and specialty ingredients activities that supply fats and proteins to the feed, pet food and food industries. By upgrading waste fats into a premium transportation fuel, the joint venture effectively adds a higher-value outlet for by-products that originate in Darling’s processing of animal carcasses and food production residues, linking the company’s environmental services role to the energy transition narrative that appeals to regulators and some investors. The scale and capital intensity of the Diamond Green Diesel platform also mean that its earnings contribution can be more volatile than Darling’s traditional ingredient businesses, as margins move with feedstock prices, diesel spreads and policy credit values, but over recent years management has highlighted the fuels segment as a strategic growth area and an important differentiator from more conventional rendering peers. In its public filings and investor presentations, Darling regularly positions Diamond Green Diesel as a centerpiece of its decarbonization efforts and a proof point that waste-derived raw materials can support large-scale, profitable low-carbon fuel production. A recent Darling Ingredients investor presentation breaks out Diamond Green Diesel’s capacity, joint venture structure and feedstock sources as a key part of the company’s long-term growth story.

For Darling Ingredients, the Diamond Green Diesel platform has become a central pillar connecting its historical strength in rendering and waste collection with the fast-evolving low-carbon fuels market, broadening the company’s exposure beyond animal feed, pet food and food ingredients into transportation energy and aviation. Shares of Darling Ingredients (ISIN US2372661015) traded on the New York Stock Exchange at around $42 on 06/14/2026, reflecting investor attempts to balance the cyclical and policy-sensitive earnings from renewable diesel against the steadier cash flows of the company’s legacy ingredient operations.

Diamond Green Diesel in brief: key data

• Product: Diamond Green Diesel renewable fuel platform
• Manufacturer: Darling Ingredients Inc. / Valero Energy Corporation (joint venture)
• Category: Flagship renewable diesel and sustainable aviation fuel
• Launch date: Initial Norco, Louisiana plant start-up in 2013; subsequent expansions and Port Arthur, Texas plant commissioned in the early 2020s
• MSRP / Price: Sold business-to-business; pricing linked to diesel benchmarks and renewable fuel credit values rather than a consumer list price
• Availability: Bulk renewable diesel and sustainable aviation fuel primarily in North America, distributed via pipelines, terminals, barge and rail to refiners, fuel marketers and airlines
• Target audience: Refiners, fuel distributors, commercial fleets, municipal transport operators and airlines seeking low-carbon drop-in fuel options
• Key differentiator / USP: Large-scale, waste-lipid-based renewable diesel and aviation fuel platform integrated with Darling’s global rendering and used cooking oil collection network

This article was a.i.-assisted and editorially reviewed. Product information without warranty; prices and availability may change at short notice. Not investment advice and not a buy or sell recommendation. Trading involves risk up to and including the total loss of invested capital.