PART 2: Using Biodiesel in Cold Weather Months

Welcome to Part 2 of our three-part series on cold properties of fuels. Previously, we defined Cloud Point and cold-flow parameters. If you missed it, you can catch up here.

What Are Some Common Myths About Biodiesel Use in Cold Weather?
Not everyone knows that distillation has a major impact on biodiesel’s cold weather performance. Distillation doesn’t affect the Cloud Point of biodiesel, but biodiesel that has been fully distilled can be managed and handled just like petroleum diesel, whereas biodiesel that is not fully distilled could still have issues at or above the Cloud Point of the final fuel blend. To put it another way, blended fuels made with distilled biodiesel can be managed without the temperature buffers that some users of biodiesel blends have historically applied.

There is also a misconception about how much impact biodiesel has on the Cloud Point of a blended fuel. REG has found that the Cloud Point of B5 (that’s 5% biodiesel, 95% petroleum diesel) is the same as that of the 100% petroleum diesel blended to make the B5, regardless of the biodiesel’s Cloud Point. And lower Cloud Point biodiesel (i.e., Cloud Point lower than 50° F) doesn’t significantly increase the petroleum diesel’s Cloud Point, even in B20 blends. This makes sense when you consider that, even with a B20 blend, the majority of the fuel is petroleum diesel; so the biodiesel has less of an impact on the finished fuel Cloud Point than some people assume.

What Is the Simplest Way to Continue Using Biodiesel in Cold Temperatures?
According to ASTM D975 — the diesel fuel specification — B5 is considered the same as diesel fuel, so a fleet could run on it in winter the same way they’d use straight petroleum diesel. Beyond B5, using a high-quality biodiesel supply (for example, a distilled biodiesel) for the biodiesel portion of the blend and using tried-and-true cold flow improvers for the diesel portion of the blend will allow for higher biodiesel blends in the winter months than most people have considered, even in the coldest locations.

What Makes Biodiesel Worth Using in the Cold?
Biodiesel allows many fleets to meet various incentives and mandates. It provides the same lubricity, pollutant reduction and fossil carbon emissions reduction benefits in the winter as in the summer. It also helps fuel users meet corporate Environmental, Social and Governance goals, and it’s simply the right thing to do for our environment.

To hear a more in-depth conversation about cold weather biodiesel use, check out our podcast episode on the topic.

 How Does Storage Fit into the Equation?
Storage does not impact a fuel’s Cloud Point, but Cloud Point affects fuel storage management. All fuel — whether it’s straight diesel or B50 — should be stored so the fuel’s temperature remains above its Cloud Point. For both 100% petroleum diesel and biodiesel blends made with distilled biodiesel, we recommend the fuel be stored at least a few degrees above the Cloud Point of the fuel. If a biodiesel blend is known to be made with undistilled biodiesel or the supply quality of the biodiesel is unknown, we recommend storing the fuel at least 10º F above the Cloud Point of the final fuel blend.