In the spirit of the season, lets look at winter weather performance of five alternative fuels. After all, what good is your electric, hydrogen or CNG car if it won’t start in the cold?
Of all the alternative fuels, biodiesel is the most susceptible to the cold. In fact, even petroleum diesel is susceptible to the cold — anti-gel additives are common in the winter, as well as blending with kerosene or even gasoline when it gets really cold. The only way to effectively winterize biodiesel is to blend it with winterized petroleum diesel. With B20 (20% biodiesel) in my tank, my Jetta TDI started up first try this morning at a chilly 25° F.
There are a variety of anti-gel additives on the market all claiming to work on pure biodiesel, but from the testing we did at SeQuential-Pacific’s labs, none are worthwhile. I once even got a salesman to admit his additives didn’t work (he promised me they were close to figuring it out though…).
The source of biodiesel will change its cold weather performance as well. For instance, palm oil biodiesel will gel at very high temperatures, whereas Algae biodiesel or camelina will gel at lower temperatures making them more appropriate for cold weather driving.
In its pure form, ethanol has some serious cold weather problems. When pure ethanol is cold, it releases fewer fumes, making it harder to start. To compensate for this, gas stations add more gas into the mixture – this is why labels for E85 (85% ethanol) state that there is a minimum of 70% ethanol in the pump. For lower blends of ethanol, cold weather is not an issue, due to the predominance of gasoline in the blend.
3. Battery/Electric Car
As some of you have surely experienced this winter, batteries have a hard time in the cold, especially those of the Lead-Acid persuasion. They put out less energy and sometimes an old battery will simply give up the ghost on a frozen morning. A little bit of precaution can make this a non-issue; you can insulate your battery, add a block heating system (easy if you have a plug-in car) or have an oversize starting battery. And of course, new battery technologies promise to improve on the cold weather problem.
Since a singular design for hydrogen-powered vehicles has not won out yet, and cold weather performance varies by design, this is a subjective call. Vehicles using liquid hydrogen have to keep the fuel refrigerated anyway… no problem there. Ideal hydrogen fuel cells produce only water vapor as a byproduct. As long as there is a mechanism for clearing water from the fuel cell, there would be no problem; otherwise fuel cells would run the risk of freezing solid overnight in the cold.
1. Compressed Natural Gas
With no major drawbacks, CNG is clearly the best performing cold weather alt-fuel. CNG is kept in a gaseous state (it is mostly methane) and under significant pressure; even in the cold it has no problems igniting. Simple as that.
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