What B100 is, technically
B100 is a fuel produced from vegetable oils, animal fats, or waste cooking oil through a chemical process called transesterification. The triglyceride molecules in the feedstock react with methanol to form fatty-acid methyl esters (FAME, the actual biodiesel) and glycerin (a byproduct). What gets sold as B100 is purified FAME meeting ASTM D6751.
D6751 specifies four grades:
- No. 1-B and No. 2-B describe sulfur content (15 ppm versus 500 ppm).
- Within each grade, S15 and S500 designations specify the cold-soak filterability test result.
Spec parameters that matter most for end users:
| Parameter | D6751 requirement | Why it matters |
|---|---|---|
| Flash point | 93°C minimum | Storage and transport safety; about 35°C higher than petroleum diesel |
| Sulfur | 15 ppm (S15) or 500 ppm (S500) | S15 grade is required for use in 2007+ on-highway engines with diesel particulate filters |
| Cloud point | Reported (no max specified) | Determines cold-weather operability for the specific batch |
| Oxidation stability | 3 hours minimum (Rancimat) | Determines safe storage life; higher numbers mean longer shelf life |
| Free glycerin | 0.020% mass max | Excess glycerin causes injector deposits and filter plugging |
| Water and sediment | 0.050% volume max | Water supports microbial growth and corrodes fuel systems |
Source: ASTM D6751 standard summary via AFDC. The full standard is available from ASTM International for purchase.
Engine compatibility — narrower than B20
This is the part that disqualifies most users. Major on-highway OEMs cap B-level approval at B20 for standard production engines:
- Ford Power Stroke: B20 maximum. Use of fuel above B20 can cause engine or after-treatment damage and is not warranty-covered.
- Cummins on-highway: B20 maximum on standard production engines. Cummins offers B100-capable engines and conversion kits for specific industrial and fleet applications, but these are not interchangeable with standard production engines.
- GM Duramax: B20 maximum on current models.
- Detroit Diesel, Caterpillar, Navistar: B20 maximum on most current on-highway engines.
B100 approvals exist primarily in:
- John Deere agricultural engines: B100 approved on certain Tier 4 Final agricultural engines, subject to additional service requirements.
- Optimus Technologies-converted heavy-duty fleets: aftermarket B100 conversion kits for Cummins and Detroit Diesel engines, used by transit agencies and municipalities.
- Older indirect-injection diesels: Mercedes-Benz pre-2007 indirect-injection engines and similar designs were often informally compatible with B100, though this is no longer warranty-relevant for current vehicles.
- Stationary engines and generators: many natural-gas/diesel generators have B100 approvals or modifications available.
If you have a specific engine and you want to run B100, the right move is to request the OEM's current biodiesel position statement in writing, then verify the specific engine serial number is covered.
Energy content and fuel economy
B100 carries about 119,550 BTU per gallon, compared to roughly 128,488 for petroleum diesel — about 7% lower. This translates to a real-world fuel-economy drop of about 7% in vehicles approved to run it.
For a fleet, this means a vehicle that gets 8 mpg on petroleum diesel will get about 7.4 mpg on B100. The economics depend on the price per gallon spread (often favorable for B100 when biodiesel-tax-credit benefits flow through) and the value of the GHG reduction (LCFS credits in California, RFS RIN values nationally).
Cold-weather operation
This is B100's biggest practical limitation. The cloud point of B100 is typically 30-40°F, depending on feedstock — soybean B100 clouds around 32°F; tallow-derived B100 can cloud as high as 60°F. Below the cloud point, wax crystals form and start plugging filters. Below the pour point, the fuel won't flow at all.
Cold-weather management options for B100 fleets:
- Heated tanks and lines: keep fuel temperature above the cloud point. Common on transit buses and refuse trucks operating B100 in northern climates.
- Cold-flow improver additives: lower the cold-filter-plugging point by 5-15°F, depending on the additive and the base fuel.
- Seasonal switching: many B100 fleets switch to B20 or B5 for the coldest months of the year, then return to B100 in spring. This is the most common pattern for school bus fleets.
- Feedstock selection: B100 from canola, sunflower, or used cooking oil with low saturated-fat content has a lower cloud point than soy- or tallow-derived B100.
Storage and shelf life
B100 oxidizes faster than petroleum diesel. Without antioxidant additives, B100 oxidation stability ranges from a few months to about 12 months depending on feedstock and storage conditions. With antioxidants, 12-24 months is achievable.
Practical storage rules for bulk B100:
- Store under nitrogen or in sealed tanks to limit oxygen exposure.
- Monitor the water bottom; biodiesel attracts more water than petroleum diesel, and the fuel-water interface supports microbial growth.
- Test acid number and oxidation stability before use if fuel has been stored more than six months.
- Keep tanks above the cloud point of the fuel — heated storage in winter is common.
Where B100 is sold
Retail B100 is rare. The AFDC station locator does include the small number of public B100 stations alongside B20 stations, but most US B100 volume moves through:
- Direct deliveries to transit agencies, school districts, and municipal fleets.
- Agricultural cooperatives selling to member operations.
- Truck-stop fleet contracts at locations with on-site biodiesel storage.
- Industrial operations using B100 in stationary engines or generators.
If you're a small fleet or an individual looking to source B100, your most likely path is contacting a regional biodiesel producer directly. Clean Fuels Alliance America publishes a member directory; state-level renewable fuels associations (Iowa RFA, Minnesota Biofuels Association, others) maintain similar lists.
For everyday purchases of biodiesel, B20 is the more practical option for most operators. Use the station locator to find B20 stations near you.
Where to buy B99 or B100
Public B99/B100 pumps are rare. As of September 2026 the DOE's station database lists 23 public stations selling B99 or B100 — out of 1,997 public biodiesel stations overall. Nine of the 23 are in Hawaii, where Pacific Biodiesel runs its own network. The rest are scattered one or two to a state:
| State | City | Station | Blends |
|---|---|---|---|
| Hawaii (9) | Honolulu, Kahului, Maalaea, Lahaina, Keaau, Kailua-Kona, Kaumakani | Pacific Biodiesel, Minit Stop, HFN Shipman, Carl's Junior 76 | B99, some B20 |
| Washington | Seattle | Dr. Dan's Alternative Fuels Werks; Hans Foreign Car Repair | B99 |
| Oregon | Bend | Quickway Market | B99 in summer, B20 |
| Arizona | Phoenix | Western States Petroleum | B99, B20 |
| Colorado | Commerce City | Shoco Oil | B99, B20 |
| Utah | Midvale | ROC Fuel | B99 |
| Texas | Dallas | Pilot Travel Center #433 | B99 |
| Iowa | Des Moines | Flying J / Pilot Travel Center #373 | B99 |
| Illinois | Decatur | Pilot Travel Center #368 | B99 |
| South Dakota | Baltic | Midway Service Station | B100, B20, B5 |
| Ohio | Columbus | Benchmark Biodiesel | B100, B20, B5 |
| New York | Oneonta | Mirabito Convenience Store #69 | B99 |
| Maine | Portland | Maine Standard Biofuels | B99, B20 |
| Rhode Island | Cumberland | TH Malloy and Sons | B99 in summer, B20 in winter |
Source: U.S. DOE Alternative Fuels Data Center, pulled September 20, 2026. Call before driving — several of these are small operators with limited hours. Use the locator for addresses and phone numbers.
Buying in bulk. If there's no pump near you, the practical route to B99/B100 is a fuel distributor. Many petroleum jobbers that serve farms and fleets can deliver B99 or B100 by the tote (250–330 gal) or transport load; ask specifically for fuel meeting ASTM D6751 with a certificate of analysis, and ask whether the producer is BQ-9000 accredited. Biodiesel plants themselves generally sell by the truckload to distributors rather than to the public, though a few smaller producers (like the Maine and Hawaii operations above) run a retail pump on site.