Going Green: Should you convert to Biodiesel? How does it work?

Every once in a while you might see a car go by with a sticker proclaiming “Powered by soybeans” or “I run biodiesel! Ask me how!” or some such message. No doubt you’re curious, as I was. What are these mysterious frybrids, and do you want one? Your curiousity will be satisfied after the link.

Biodeeez nuts
Although the popularity and visibility of alternative fuel sources has been increasing in the last decade or so, the idea of biodiesel is extremely old. In fact, old Rudolf Diesel himself ran one of his engines on peanut oil at the request of France (technically not biodiesel but you get the idea). The reason it never took off was simply that petroleum became a more feasible option and the infrastructure became built around that instead. Well, now greenhouse gas emissions, rising oil prices, and geopolitical politics have nudged the spotlight a bit toward biofuels again, and for some people it’s a great deal.

Essentially, it’s any kind of fatty oil that’s been purified and transesterased (a chemical substitution process), at which point it can be run in pretty much any diesel engine with little or no modification. One of the ideas of the diesel engine was fuel independence. Farmers could use their own corn oil in their diesel tractors, Siberians used their extra vodka, and so on. Nowadays, the petroleum industry has had so much infrastructure that it can be difficult to run a biodiesel car regularly. But that’s changing. People want to rely on foreign oil less and recycle what we have more. Thus the movement to use biofuels was reborn.

If you have a diesel engine, chances are all you have to do is find out where to get some biodiesel locally. This is easier than it sounds – there are services online for finding a place, and I imagine if you just ask your mechanic, he or she could point you in the right direction. Most likely you’ll be running a mix of petro-diesel and biodiesel. The label B__ describes the ratio: B20 is 20% biodiesel, B40 40% and so on. Price is difficult to predict, but considering how much gas costs these days, I doubt you’d be saving a lot of money by sticking with fossil fuels exclusively.

You can try to make your own, but I wouldn’t trust myself to do it and unless you’re a chemical engineer you shouldn’t either. It’s not as simple as driving to McDonalds, hijacking their fryer, and pouring it into your gas tank. There’s a chemical process involved (check it out) to make sure the stuff works right, to say nothing of all the fry bits that would end up in your fuel filters.

So what is biodiesel?
The Good
So other than feeling good about not contributing to the oil problem, what’s good about biodiesel? As it turns out, quite a lot:

  • Biodiesel has far lower harmful emissions than petroleum-based fuels
  • The fuel itself is nontoxic; a leak or tanker tipping over won’t hurt a fly (unless it drowns)
  • It’s sustainable; there’s no biodiesel reservoir we’re emptying out
  • It runs cleaner, smoother, and quieter thanks to biodiesel being a natural lubricant

The Bad
Nice, right? Of course, there’s a flip side. Pure biodiesel has poor performance in cold weather; below freezing it becomes slushy. This usually isn’t a problem as the biodiesel will be cut with regular diesel and you can go safely down to -15F. Because biodiesel is a solvent, it will corrode rubber hosing and seals; ask your mechanic if you don’t know whether you have these. Most cars have synthetics instead of rubber and have for decades, but you never know. However, biodiesel’s solvent nature also means it will clear out a lot of the junk that’s been clogging your engine, so replace your filters after a tank or two.

The Nasty
One thing biodiesel proponents tend to gloss over is the fact that we’d need a huge amount of crops to fuel ourselves. Even as it is, half the world’s soy crop goes into fuel, and ethanol faces a similar problem. So we grow more, right? Wrong. Fuel crops are leaders in deforestation due to the huge amount needed, and it may be that the carbon footprint of destroying millions of acres of the Amazon (where soy is the biggest crop) far outweighs the benefits of reduced emissions. That’s a difficult question and one that is by no means settled, so it’s worth considering.

Other sources for biodiesel are being researched, such as algae that produce it naturally, but these have nowhere near the capacity to fill demand at this time. Ideally there would be a clean and harmless way to produce the fuel as well as the fuel itself being relatively harmless, but that’s not the case. If it matters to you, you can find out where your biodiesel is coming from or start making your own from waste vegetable oil or some such.

It’s worth mentioning that there are also conversion kits available, like the “Frybrid,” which allow your car to run on pure vegetable oil that has been heated up to reduce viscosity. These are not biodiesel per se, but are close enough that you might consider one instead. The only trouble is acquiring enough vegetable oil to run it, but you probably get pretty good at that after a while.

Essentially, biodiesel is still a mixed bag. It’s got its own set of pros and cons, but none of the benefits is a knockout punch when you consider the drawbacks. At this point its a matter of whether you want to do it, not whether you should.