Wondering what is renewable diesel and how it differs from biodiesel? It is a hydrocarbon fuel made from fats and oils that is chemically like petroleum diesel, whereas biodiesel is an ester.
It is one of several liquid fuels covered in our guide on what are biofuels.
| Item | Value |
|---|---|
| Chemistry of renewable diesel | Only hydrogen and carbon, a hydrocarbon fuel like petroleum diesel |
| Biodiesel energy content versus petroleum diesel | About seven percent less energy by volume |
| Cloud point of soybean biodiesel | About 34 degrees Fahrenheit |
| Cloud point of petroleum diesel | About 16 degrees Fahrenheit |
| U.S. renewable diesel and other biofuels capacity, January 2023 | 3 billion gallons per year |
The figures come from farmdoc daily at the University of Illinois and the U.S. Energy Information Administration. They can change, so check the sources before you rely on them.
What is renewable diesel, in plain terms?
Renewable diesel is a liquid fuel made from renewable raw materials such as vegetable oils and fats. Its molecules are the same kind found in fuel refined from crude oil. The U.S. Energy Information Administration describes it as a fuel “chemically equivalent to petroleum diesel and nearly identical in its performance characteristics”, in its 2023 capacity report.
Farmdoc daily puts the chemistry this way: renewable diesel “only contains hydrogen and carbon, making it a hydrocarbon fuel just like petroleum diesel”. That is the core of the matter, because it decides how the fuel behaves in tanks, pipes and engines.
How is renewable diesel made?
The most common route in the United States is hydroprocessing, also called hydrotreating. The farmdoc daily explainer says that “the catalyst triggers reactions of hydrogen with the feedstock under high temperature and pressure, forming mostly water and liquid hydrocarbon molecules that are suitable for use as fuel with additional processing”.
The steps resemble those used in an oil refinery. That is one reason existing refineries have been converted to make it.
Typical raw materials include:
- Used cooking oil and animal fats.
- Vegetable oils such as soybean oil.
- Greases and other fatty residues from food processing.
Farmdoc daily calls hydroprocessing the most common process in the U.S.
After hydrotreating, the product is a mix of hydrocarbons that is processed further to suit a diesel engine. Unlike transesterification, the reaction removes oxygen as water rather than leaving it in the fuel molecule.
How is biodiesel different?
Biodiesel is usually called FAME, short for fatty acid methyl ester. It is made by transesterification, a reaction that, in the words of farmdoc daily, “converts organic fats and oils into fatty acid alkyl esters by reacting them with alcohols and catalysts”.
The same source gives a typical mass balance: 100 pounds of vegetable oil or fat reacted with 10 pounds of methanol gives about 100 pounds of biodiesel and 10 pounds of glycerol. The glycerol is a co-product that can go into animal feed or chemical processes. For a step-by-step view, see our explainer on how is biodiesel made.
Farmdoc daily stresses that “FAME is not a hydrocarbon fuel like petroleum diesel”. Biodiesel contains oxygen, which brings a different set of properties.
Renewable diesel versus biodiesel: the practical differences
The chemistry shows up in everyday use. Here are the main contrasts reported by farmdoc daily.
- Energy content: because FAME contains oxygen, it has approximately seven percent less energy by volume.
- Cold weather: the cloud point of soybean FAME is approximately 34 degrees Fahrenheit, against around 16 degrees Fahrenheit for petroleum diesel. Fuel starts to turn cloudy at a higher temperature.
- Blending: FAME is blended with petroleum diesel for final use, with common blends of B5 (up to 5 percent biodiesel) and B20 (6 to 20 percent biodiesel).
- Blending of renewable diesel: it “does not need to be blended with petroleum diesel for it to be used as a ‘spec’ fuel in modern diesel engines”.
In short, renewable diesel behaves like the fuel your engine already burns, while biodiesel is a different molecule that is used within limits. Always check your engine maker’s guidance on the blend level that is allowed.
How big is the market, and is it growing?
In January 2023, U.S. capacity of renewable diesel and other biofuels reached 3 billion gallons per year, “surpassing U.S. biodiesel production capacity for the first time”, according to the Energy Information Administration. The agency began collecting those data in 2021.
Growth has since slowed. A later EIA note reports that renewable diesel and other biofuels capacity rose by just 391 million gallons per year in 2024. It also names a plant as the second-largest in the country, behind Diamond Green Diesel’s 982-million-gallon-per-year plant in Norco, Louisiana.
The same note reports that Monroe Energy and Chevron stopped co-processing renewable diesel at refineries in Trainer, Pennsylvania, and El Segundo, California.
Capacity is not output, and plants can open, close or switch fuels from year to year. Treat any single year’s number as a snapshot, not a forecast.
Why the 2020 and 2021 wave happened
The EIA explains that low refinery margins and rising biofuel credit values in 2020 and 2021 prompted a wave of renewable diesel capacity announcements. Policy matters a great deal here. The agency also cites rising targets for state and federal renewable fuel programs and the renewal of biomass-based diesel tax credits.
For a reader, the lesson is that supply of these fuels follows policy and margins as much as engineering. A change in either can shift which fuel a region sees at the pump.
How should you compare the two fuels?
A fair comparison looks past the label and checks a short list of points:
- The chemistry: hydrocarbon or ester.
- The blend level and whether your engine maker accepts it.
- Cold-weather behaviour, especially cloud point where winters are harsh.
- The feedstock and the lifecycle emissions claim behind it.
- Local supply, since availability depends on regional plants and policy.
No single fuel wins on every point. Biodiesel plants give a useful glycerol co-product, while renewable diesel fits existing equipment more easily.
Does either fuel cut emissions?
A simple label such as “renewable” does not settle the climate question. Our piece on are biofuels carbon neutral explains why lifecycle accounting matters.
When you compare fuels, ask for a lifecycle figure from an independent method, and note which feedstock it assumes.
Frequently asked questions
Is renewable diesel the same as biodiesel?
Show answer
No. Renewable diesel is a hydrocarbon, while biodiesel is a fatty acid methyl ester made by transesterification. They can start from similar fats and oils but end up as different molecules.
Can renewable diesel go straight into a diesel engine?
Show answer
Farmdoc daily says it does not need blending to serve as a “spec” fuel in modern diesel engines. Check your engine maker’s guidance and your fuel supplier’s specification first.
Why does biodiesel have less energy?
Show answer
Biodiesel contains oxygen, which gives it approximately seven percent less energy by volume than petroleum diesel, according to farmdoc daily.
Which fuel handles cold weather better?
Show answer
The cloud point of soybean biodiesel is about 34 degrees Fahrenheit compared with around 16 degrees Fahrenheit for petroleum diesel. This comparison does not establish renewable diesel’s cloud point.
