Quick answer
Renewable diesel (RD, sometimes labeled R99 or R100) is a hydrotreated fuel made from fats, oils, and greases. Chemically it's nearly identical to petroleum diesel, so it runs in any diesel engine with no modifications and no blending limits. Compared to petroleum diesel, RD reduces lifecycle CO₂ emissions by roughly 60–80% depending on feedstock.
Renewable diesel vs. biodiesel — they're different
| Renewable diesel (RD) | Biodiesel (FAME) | |
|---|---|---|
| Chemistry | Hydrocarbon (hydrotreated) | Fatty acid methyl ester |
| Drop-in? | Yes, up to 100% | Typically blended to B5–B20 |
| Cold-weather performance | Comparable to petroleum diesel | Can gel earlier without additives |
| OEM approval | Broad; spec ASTM D975 | Limited at higher blends |
| CO₂ reduction (lifecycle) | ~60–80% | ~50–80% depending on blend |
What's the same as petroleum diesel
- Energy density and MPG — fleets typically see no meaningful change.
- Fueling and storage infrastructure.
- Use in existing emissions systems (DPF, SCR).
- OEM warranty coverage on most modern diesel engines.
What's different
- Lifecycle CO₂: 60–80% reduction is the headline. Important for fleets with sustainability commitments or low-carbon fuel-standard (LCFS) exposure.
- Local air quality: typically lower NOx and particulate emissions versus conventional diesel.
- Cold-weather behavior: generally as good as or better than petroleum diesel, depending on the spec.
- Smell and visible smoke: noticeably lower at the tailpipe in many duty cycles.
Price and availability
In California, RD now makes up a meaningful share of the on-road diesel pool, supported by LCFS credits that bridge the production-cost gap. Pump prices for R99/R100 are often within a few cents of petroleum diesel — sometimes cheaper. Outside California and a handful of West Coast states, availability is uneven and pricing premiums are larger.
Who should care today
- Fleets with sustainability reporting commitments — RD offers a fast, low-friction Scope 1 reduction.
- Fleets operating in California, Oregon, Washington, and other LCFS jurisdictions.
- Operators concerned about NOx and particulate compliance.
- Buyers evaluating diesel-vs-EV decisions where RD effectively de-risks the timeline by greening the existing fleet.
What's next
Production capacity is still growing in North America, with new refineries and conversions coming online. Feedstock — used cooking oil, animal fats, soybean oil — remains the constraint. Watch policy: LCFS programs in more states, federal blender's tax credits, and the IRA's clean-fuel production credit will shape how cheap RD gets and where it shows up first.
About these numbers
Emissions and price ranges above reflect public data from CARB, EIA, and producer disclosures. Lifecycle CO₂ reductions vary by feedstock, plant, and pathway. Local pricing changes weekly. Verify against current LCFS credit pricing and supplier quotes for any procurement decision.
