I don’t want to scare people away with my hardcore environmental tales but I do like to tell people about my greasecar. It’s a 1997 VW Jetta with a turbo diesel engine that has been adapted to burn straight vegetable oil. The idea is that I can burn waste vegetable oil (from all those French fry joints) instead of petroleum diesel which will achieve three goals: utilizing a waste product, reducing dependence on petroleum products, and reducing the amount of air pollution generated. (The third one is debatable but at least it SMELLS a lot better.) Oh, and I generally get my vegetable oil for free as opposed to paying $3.50/gallon for petroleum diesel.
The idea is simple. The diesel engine was originally designed to burn vegetable oil so today’s diesels can also burn vegetable oil IF it is preheated to reduce the viscosity (make it thinner). My car has a special tank in the trunk that I fill with filtered vegetable oil. I start my car with petroleum diesel from the regular gas tank, use the heat from the engine to heat up the vegetable oil, and when it’s hot I push a button to start pumping from the vegetable oil tank instead. At the end of my ride I switch back to petroleum diesel to purge all the lines. This is so when my car cools down, the engine doesn’t gum up with vegetable oil.
Just to clarify, a straight vegetable oil (SVO) system is different than a biodiesel system. Biodiesel is a product made by combining vegetable oil with lye and methanol to create a fuel that is very similar to petroleum biodiesel. The cool part is that you can put it in the regular tank of any diesel vehicle and don’t need to modify the vehicle to use it. (There are a couple of exceptions; biodiesel has a nasty habit of eating through certain types of rubber so there are some older cars that would need to have their gaskets switched out.) The downside of biodiesel is that you have to make it, which generally involves some kind of processing system, and it generates some nasty byproducts. This is not surprising since lye (drain cleaner) and methanol (antifreeze) are both pretty nasty to begin with.
I decided to go the straight vegetable oil route because I found biodiesel production to be intimidating. There are definitely people out there who have awesome setups in their garages but they tend to be the tinkering types. It’s also possible to buy biodiesel but most of that is made from new vegetable oil rather than waste vegetable oil. I prefer to see new vegetable oil being used as people food instead of running my car.
My greasecar has been pretty good but there was definitely a steep learning curve and I really feel like I haven’t done as well as I could have. There are a few ongoing problems I have chosen not to deal with – for example, the gauge for the vegetable oil tank has never worked and my trunk has a permanent coating of grease from spills. Filtering the waste oil is a HUGE pain and I still haven’t figured out a good system. I also can only run on grease when the temperature is above about 50 degrees Fahrenheit. Diesels don’t like cold weather and veggie oil only makes it worse. In the end, it has been a little too easy to run on petroleum diesel instead of hassling with veggie oil but overall I’m glad I did the conversion.
I have a lot more to say on the subject so expect future posts about the nitty gritty details of conversion, turf wars for used vegetable oil, my internal debate about whether or not running my car on grease can really be considered environmentally benign, and my frustration with the biofuels movement.