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Biodiesel or SVO?

Although biodiesel is drawing increasing attention from automakers, policymakers and farmers, there is another biofuel that can be used in diesel engines: straight vegetable oil, or SVO.

The two approaches, although apparently similar, are operationally and philosophically quite different. Broadly stated, you can either modify (refine) plant oil to create biodiesel to run in an unmodified diesel engine, or you can modify an engine system to allow it to use unaltered vegetable oil.

Journey to Forever, a terrific resource on multiple aspects of sustainability, puts it this way:

Does the SVO option work? Yes—IF you go about it the right way. It’s not quite that simple a choice. For one thing, if you want to use waste vegetable oil, which is often free, you’re going to have to process it anyway, though less so than to make biodiesel. And it still might not be a very good fuel.

The main problem is that vegetable oil is much more viscous (thicker) than conventional diesel fuel. It must be heated (thinned) so that it can be properly atomised by the fuel injectors. If it’s not properly atomised, it won’t burn properly, forming deposits on the injectors and in the cylinder head, leading to poor performance, higher emissions, and reduced engine life.

Nonetheless, experience is showing that SVO systems are a practical proposition with a lot of advantages to offer, not least of all that using SVO can be cheaper than turning it into biodiesel and uses less energy than making biodiesel does.

But you have to be willing to take on the modifications. For those inclined to a D-I-Y project, there are a number of resources and kits available.

I will start including SVO on the site, including product news and lifecycle and emissions studies.

A few SVO links and online resources


Steve Spence

To see a WVO conversion being installed, and to learn how to do one yourself, see


WVO = Waste Vegetable Oil

SVO = Straight Vegetable Oil


Just FYI, SVO/WVO have different implications as far as emissions when compared to biodiesel. For example, the combustion in a vehicle running SVO/WVO releases acrolein, a known carcinogen, but this is absent from biodiesel as a result of the chemical differences.

This is just one example, but people thinking about WVO/SVO instead of biodiesel should do their research if the motivation is environmentalism...


We are the leading promoter of jatropha in India for biodiesel production.
Can we use jatropha oil directly without going for transesterification process?
Sir, since we are promoting farming for the biofuel , if SVO OF JATROPHA CAN BE DIRECTLY USED FOR RURAL MACHINARIES it would be a great help in success of our project as economic viability would be enhanced.
kindly explain the process of utilisation of SVO or modification in vehicles required
centre for jatropha promotion


we r doing our project on biodiesel(direct blending)can u help to our project.
Thanking you.

Tony O


can you point me to some more info on this acrolein thing. I'm looking at what levels are produced and at what levels is it really toxic. Their are many things that in high levels can cause cancer but in small amounts do not, so knowing these points is fairly important.

abhijit vasant pisal

i am engg. student , trying to use jatropha as a fuel in automotive cars directly without Transesterification process . I am having difficulties in doing this. Can you help me.

Garth Richardson

Can one safely blend used vegetable oil with commercially available diesel fuel with no negative effects and up to what proportions. I have in mind 30% veg oil to 70% commercial diesel. This in a normally aspirated diesel engine? This vehicle runs in subtropical areas where no temperatures below zero are encountered.

Steve Spence

The acrolein issue was a red herring. It was discovered burning wvo on a bunsen burner in a lab by folks who have never touched a diesel engine. WVO emissions are very similar to biodiesel emissions. No, you cannot mix vegetable oil with diesel without heat in most engines and environments. Damage to the injector pump and injectors usually follows. If you want to run wvo, do it right with two tanks and heated oil.



can u tell me what is transesterification? can u tell hou to convert jatropa oil to bio diesel in detail.

thanking you sir,



i am an engineering student want to do a project on the perfrmance of jatropa bio diesel. could u please explain about esterification of jatropa oil

thanking u sir



You can find all the information about biodiesel and WVO in the journeytoforever link up there. Dig thru that site and read it carefully. Dont be lazy to do research study is not always the case of copy n paste :)

Schuyler Spears

Can anyone one give me a link and/or info comparing emissions outputs of a properly implemented SVO system compared to that of a modern diesel engine?


i am engg. student,working on Jatropa as a Bio-Diesel to find out the performance of I.C.Engine. How should i carry the test & on which point i should be
thanking u

vijay prakash

What are the modifications required in an IC engine if we use jatropha bio-diesel as the fuel.Incase if optimum modifications be made will that be efficient?
kindly clarify me at the earliest.

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