Biodiesel blends for fleets: B5, B20 and what to ask
Some fleets want biodiesel for cost, contracts, or emissions goals. Before you switch a yard tank, know what the blend number means and what your engines can take.
What the blend numbers mean
The number after the B is the share of biodiesel in the fuel. The U.S. Department of Energy describes B5 as up to 5 percent biodiesel and B20 as 6 to 20 percent. B100 is pure biodiesel.
According to the Department of Energy, the ASTM D975 diesel spec lets fuel with up to 5 percent biodiesel be called diesel fuel with no separate label at the pump. Your regular diesel may already contain some.
B20 has its own spec, ASTM D7467. B100 is mostly used as a blendstock and must meet ASTM D6751. Ask your distributor which spec the fuel they deliver meets and put it in writing on the order.
Check the engines first
The Department of Energy says B20 and lower blends can generally run in current diesel engines without changes, and many engine makers approve B20. It also tells users to check engine warranty statements first.
Mixed fleets are the hard part. One older machine or one engine maker that does not approve the blend can decide what goes in a shared yard tank. Make a list of every engine that pulls from the tank.
Cold weather and storage
The Department of Energy notes that higher biodiesel blends can gel in cold temperatures and may present storage issues. Ask how the blend you are offered handles the coldest weeks where your tank sits.
Higher blends can also loosen old deposits in a tank or fuel system and clog filters at first. Check the tank for water and sludge before the first load, and keep spare filters on hand for the first few fills.
Biodiesel is not renewable diesel
Renewable diesel is a different fuel. The Department of Energy says it is made to be chemically the same as petroleum diesel and meets the ASTM D975 spec. Biodiesel is a different chemistry blended into diesel.
Supply differs by region. The Department of Energy says nearly all renewable diesel used in the US goes to California. Outside that market, ask whether a distributor can supply it before you plan a switch.
How to ask for a blend
Bulk Fueling does not have a biodiesel filter, so search the ZIP for ULSD and say the blend you want in the quote notes. Include the gallons, the tank size, and whether the blend must change in winter.
Questions
Is B20 cheaper than regular diesel?
Prices change by market, season, and contract. Bulk Fueling does not publish fuel prices. Ask the distributor for a quote on both straight diesel and the blend you are considering.
Do I need a separate tank for biodiesel?
Usually not for low blends, but it depends on your engines, your tank, and the blend level. Ask the distributor and check engine maker guidance before switching a shared tank.
Where can I read more about biodiesel blends?
The U.S. Department of Energy's Alternative Fuels Data Center has pages on biodiesel blends and renewable diesel, plus a biodiesel handling and use guide for fleets and tank owners.