In one paragraph: Both fuels start as vegetable oil, used cooking oil or animal fat. Biodiesel reacts that fat with methanol to make a methyl ester (FAME) that meets its own spec, ASTM D6751, and is blended into diesel as B5, B20 or B99. Renewable diesel reacts the fat with hydrogen instead, which strips out the oxygen and leaves plain hydrocarbons, so the finished fuel meets the petroleum diesel spec, ASTM D975. That one difference drives everything else: renewable diesel has no blend limit, no gelling problem and no storage penalty, while biodiesel brings better lubricity and a much bigger retail footprint outside the West Coast. R99 is 99% renewable diesel; B20 is 20% biodiesel. They are not interchangeable names.
Side-by-side
| Renewable diesel (R99, HVO) | Biodiesel (B100 / B20) | Petroleum diesel | |
|---|---|---|---|
| Chemistry | Paraffinic hydrocarbons | Fatty-acid methyl esters (FAME) | Hydrocarbons |
| Process | Hydrotreating (hydrogen, heat, pressure, catalyst) | Transesterification (methanol, catalyst) | Refining crude oil |
| Fuel spec | ASTM D975 (and EN 15940) | D6751 (B100), D7467 (B6–B20) | ASTM D975 |
| Oxygen in the fuel | None | ~11% by weight | None |
| Energy (BTU/gal) | ~123,710 | ~119,550 (B100); ~126,700 (B20) | ~128,488 |
| Cetane | 70–85 | 45–65 | 40–55 |
| Blend limit | None; 100% is a drop-in | B20 for most modern engines; B5 for many European diesels | — |
| Cloud point | About 10°F summer grade, −4°F winter grade (Neste) | ~32°F soy, up to ~60°F tallow (B100) | −10°F to 10°F |
| Storage | Like diesel; doesn’t attract water | Months; absorbs water, oxidizes | 1–2 years |
| Lubricity | Low, like ULSD; needs additive | Excellent; 2% fixes ULSD | Needs additive |
| Carbon intensity vs diesel | ~65% lower (California LCFS average) | 40–86% lower for B100 (GREET) | Baseline |
| Public U.S. pumps | 1,237, 91% in California | 1,997, led by Illinois, California, Iowa, Minnesota | Everywhere |
Sources: AFDC Fuel Properties Comparison and Renewable Diesel pages; ASTM D975, D6751, D7467; Neste MY Renewable Diesel product data; DOE/NLR Biodiesel Handling and Use Guide; Argonne GREET; CARB LCFS data; station counts from AFDC, October 2026.
How each is made
A fat or oil molecule is a triglyceride: three fatty-acid chains hanging off a glycerol backbone. Both fuels start by breaking that apart. What they do with the chains is the whole story.
Biodiesel is made by transesterification: the oil is reacted with methanol and a catalyst, the glycerol drops out as a byproduct, and each fatty-acid chain ends up with a methyl group on the end. The result is a methyl ester. It still carries the oxygen atoms from the original fat, which is why biodiesel has less energy per gallon, better lubricity, a higher gel point and a shorter shelf life than diesel. It is a good fuel, but it is chemically its own thing, so it has its own spec (ASTM D6751) and engine makers treat it as a blend component.
Renewable diesel is made by hydrotreating: the oil is reacted with hydrogen at high temperature and pressure over a catalyst, the same kind of unit a petroleum refinery uses to remove sulfur. Hydrogen strips off the oxygen (as water and CO2), the chains are left as straight paraffins, and an isomerization step branches some of them to lower the cloud point. The product is a hydrocarbon that meets ASTM D975 just as petroleum diesel does. AFDC lists six possible pathways, but hydrotreating is the only one in commercial use; it’s also why several West Coast refineries were converted to make it. Europe calls the same fuel HVO (hydrotreated vegetable oil).
The feedstocks overlap almost completely: soybean oil, canola oil, used cooking oil, tallow, distillers corn oil. That matters for price, as we get to below.
Engine approval and warranty
This is the practical difference most drivers run into. Because renewable diesel meets D975, an engine approved for diesel is approved for renewable diesel, at any blend up to 100%. Your owner’s manual doesn’t need to mention it; it’s diesel. Fleets in California run R99 in everything from 2001 pickups to new Tier 4 equipment with no change in warranty position.
Biodiesel is a blend component with a cap. Ford, GM and Ram approve B20 in their 2011-and-later diesel pickups; most heavy-duty engines built since 2007 are approved for B20; Volkswagen, Audi, Mercedes-Benz and BMW limit U.S. diesels to B5; almost no on-highway engine is approved for B100. The engine-by-engine list is on its own page.
The trap is the hybrid pump. Many “renewable diesel” pumps in California, Oregon and Washington sell renewable diesel blended with biodiesel: Chevron’s R80 + B20 and R55 + B20, for instance. The biodiesel share is what counts against your limit. R99 and R95 (which carries no more than B5) are fine for a B5-only engine; R80 + B20 is not. Our renewable diesel pages show the exact blend for every pump.
Cold weather and storage
Biodiesel’s weak points are cold flow and shelf life. Soy B100 clouds around freezing and tallow B100 near 60°F; B20 lands a few degrees above the diesel it’s blended with, which is why Midwest retailers drop to B5 in winter. Biodiesel also absorbs water and oxidizes, so the DOE handling guide suggests using B100 within about six months and Ford advises against leaving B20 in a tank for more than a month.
Renewable diesel has neither problem. It contains no oxygen and no esters, so it stores like petroleum diesel and doesn’t pull water from the air. Cold flow is set at the plant by how far the paraffins are isomerized: Neste rates its summer grade at a 10°F cloud point and its winter grade at −4°F, which is better than most No. 2 diesel. That is why Portland, where diesel can see single-digit winters, can mandate 99% renewable fuel by 2030 without the seasonal blend-down that biodiesel states use.
The one caveat from the fuel-additive industry is that HVO blends don’t always behave in a cold-filter test the way the bench number predicts, so in a very cold climate treat the cloud point as a guide rather than a guarantee. In the three states where it’s actually sold, that rarely comes up.
Energy, cetane and mileage
Renewable diesel holds about 123,700 BTU per gallon against roughly 128,500 for No. 2 diesel: 3–4% less, because paraffins are lighter than the aromatic-rich mix in petroleum diesel. B100 is about 7% below diesel, B20 about 1–2%. So on energy alone, R99 costs you a bit more mileage than B20 does, and a bit less than B100. On a truck that gets 18 mpg, R99 is worth about 0.6 mpg.
Cetane goes the other way. Renewable diesel tests at 70–85 against 40–55 for petroleum diesel and 45–65 for biodiesel. Very high cetane means a short ignition delay: quieter cold starts and slightly less combustion noise. It doesn’t add power, but drivers do notice the sound.
Lubricity is biodiesel’s win. Ultra-low-sulfur diesel lost its natural lubricity when the sulfur came out, and refiners add a lubricity package to meet spec. Pure paraffins are no better, so renewable diesel gets the same additive. Biodiesel at just 2% restores lubricity to better-than-old-diesel levels on its own, which is one reason the R95 and R80 hybrid blends exist.
Emissions
Lifecycle carbon. Both fuels carry recently-grown carbon, so both cut lifecycle greenhouse gas emissions sharply. California’s LCFS data put renewable diesel at about 65% lower carbon intensity than petroleum diesel on average across certified pathways. Argonne’s GREET model puts biodiesel at 40–69% lower for soy and canola (with land-use change counted) and 70–86% for used cooking oil and tallow. Feedstock matters more than which process made the fuel: waste-fat renewable diesel and waste-fat biodiesel land in the same range.
Tailpipe. In engines without aftertreatment, biodiesel cuts particulates, CO and hydrocarbons but can raise NOx slightly; renewable diesel cuts particulates and, in CARB’s testing, cut NOx by roughly 5% in older engines and 13% in a legacy farm engine. In engines with a particulate filter and SCR, CARB found no statistically significant NOx difference for R100 and the aftertreatment does the work for either fuel. NOx is the reason California requires biodiesel blends above B5 to be paired with a mitigation measure, and blending with renewable diesel is one of the accepted ones.
When you get both: R80/B20 and friends
If you fuel in California, Oregon or Washington you will meet pumps that are neither one nor the other. AFDC lists 1,237 public renewable diesel pumps, and most sell a renewable diesel/biodiesel blend: 76 mostly R95 with up to B5; Chevron mostly R80 + B20 in California and R55 + B20 in Oregon and Washington. Blending the two lets a retailer earn low-carbon-fuel credits on both components, meet California’s NOx rule for the biodiesel, and keep lubricity without an additive. For the driver the rule of thumb is simple: the “R” number is irrelevant to your warranty, the “B” number is everything. An R80 + B20 pump is a B20 pump as far as your manual is concerned.
Where each is sold
Retail renewable diesel is a West Coast fuel: 91% of the 1,237 public pumps are in California, nearly all the rest in Oregon and Washington, and six pumps cover the remaining 47 states. That’s not a supply problem; the 16 U.S. plants can make about 2.9 billion gallons a year, and Diamond Green Diesel in Louisiana alone makes nearly a billion. It’s that the credits which make it worth selling at a pump exist in those three states. See the renewable diesel locator.
Biodiesel is a Midwest and West Coast fuel: 1,997 public B20-or-higher stations, led by Illinois, California, Iowa and Minnesota, where state tax treatment or a blending mandate make B20 routine at Casey’s and truck stops. See biodiesel by state. Everywhere else, both fuels are bought in bulk through fuel distributors.
Cost
At the plant gate, renewable diesel costs more to make than biodiesel: hydrotreating needs hydrogen, high pressure and a refinery-scale unit, while transesterification runs at low pressure in a much cheaper plant. Both track the price of the same fats and oils, so when soybean oil or used cooking oil gets expensive, both move together.
At the pump, policy sets the price. The DOE’s quarterly Alternative Fuel Price Report (July 2026) had diesel at $4.86, B20 at $4.76 and B99–B100 at $5.42 nationally; it doesn’t track renewable diesel at all. In California and Oregon, LCFS and Clean Fuels credits paid to the supplier bring R99 to within a few cents of petroleum diesel at the same station. Outside those programs, bulk R99 usually sells at a premium over diesel, and bulk B20 at or below it. Adjust for energy: R99 needs to be about 3–4% cheaper per gallon than diesel to break even per mile; B20 about 1–2%.
Which should you use?
- Any diesel engine, West Coast: R99 is the easiest choice there is. No warranty question, no cold-weather question, lower carbon. If the pump is R80 + B20, check your B-limit first.
- Manual says B5 only (VW, Mercedes, BMW, pre-2011 pickups): R99 or R95. Avoid anything with B20 in the name.
- Modern pickup or truck, Midwest: B20 is what’s available and it’s fine; renewable diesel isn’t at retail there.
- Equipment that sits all winter: R99 or straight diesel, never biodiesel.
- Fleet buying in bulk: compare delivered price per BTU, then per credit if you’re in an LCFS state. R99 wins on handling; B20 often wins on price.
FAQ
Is renewable diesel the same as biodiesel?
No. Biodiesel is a methyl ester (FAME) made by transesterification and sold in blends such as B20 under its own spec, ASTM D6751. Renewable diesel is a hydrocarbon made by hydrotreating that meets the petroleum diesel spec, ASTM D975, and can be used at 100% in any diesel engine.
Is R99 better than B20?
For engine compatibility, cold weather and storage, yes: R99 has no blend limit, clouds well below freezing and stores like diesel. For lubricity and retail availability outside California, B20 wins. On carbon, both cut lifecycle emissions substantially and the feedstock matters more than the process.
Can I use renewable diesel in any diesel engine?
Yes. Renewable diesel meets ASTM D975, the same specification as petroleum diesel, so any engine approved for diesel is approved for it at any blend including 100%. The exception is a pump that blends renewable diesel with biodiesel, such as R80 + B20; then your engine's biodiesel limit applies.
What is HVO?
Hydrotreated vegetable oil, the European name for renewable diesel. Same process, same product. In the U.S. it is sold as R99 (99% renewable diesel with 1% petroleum) or R100.
Why is renewable diesel only sold in California, Oregon and Washington?
Those states run low-carbon fuel programs that pay suppliers credits for every gallon of low-carbon fuel, which is what makes it profitable to sell at a pump. Nearly all U.S. production flows there. Elsewhere, renewable diesel is sold in bulk to fleets rather than at retail.
Does renewable diesel get worse mileage?
Slightly. It holds about 123,700 BTU per gallon against about 128,500 for petroleum diesel, so expect roughly 3–4% lower fuel economy. B20 biodiesel is about 1–2% lower; B100 about 7% lower.