This text is a summary of hundreds of hours of internet research and personal experience by one VWAF member. Interpret it how you will. You are your own insurance, so only use Biofuels when you are sure you are ready. I accept no liability if you break your car!
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It’s a long read, but it’s a big topic!
Introduction
Biofuels are derived from recently living organisms, as opposed to Fossil fuels which are of course from fossilised organic matter. Fossil fuels contain Carbon that was removed from the atmosphere millions of years ago, and was destined to remain locked in the crude oil deep underground forever.
By burning fossil fuels, this carbon is released back into the atmosphere, effectively increasing the concentration of CO2 in the air.
Burning biofuels releases CO2 that was only recently fixed into plant matter from the air, perhaps in the last few months or years. As such it is effectively not adding more CO2 into the air. The CO2 that was recently fixed into plants (removed from the atmosphere) has simply been put back in equal amounts. This CO2 is then reabsorbed by plants, meaning that no CO2 has been added overall.
A misconception is that using biofuels puts out no CO2. This is incorrect because burning any fuel releases CO2 by definition.
The Diesel engine was originally designed to use Peanut oil. Soon after it’s invention, it was discovered that it could also run on the much cheaper (at the time) Fossil Diesel. Since then, most diesel engines have evolved to make use of the Fossil Fuel.
Biofuels take many forms
Some of the different types are explained below
BioFuel – This is the collective term for all the types. It has also been used for the fuel where Waste Vegetable Oil is cleaned, washed, dried and filtered before use. This fuel is chemically unaltered from Straight Vegetable Oil, and as such is too viscous (thick) to be used in modern diesel vehicles without modification. It is easy to make.
SVO – Straight Vegetable Oil. This is the oil you buy in the supermarket to cook food in. It can be used in older diesel engines. Newer engines require modification as the oil is too thick. SVO can be turned into Biodiesel or BioFuel using their normal processs. It is considered to make the most consistent fuel due to the fact that it has not been contaminated.
WVO – Waste Vegetable Oil. This is used cooking oil. It has picked up impurities due to the food that has been cooked in it. WVO is considered more eco-friendly as it has been recycled. SVO could have been used for cooking but wasn’t (wasteful). WVO can be turned into BioDiesel or BioFuel using their normal processes. When turning it into Biodiesel, additional processing is needed to remove the impurities.
BioDiesel – This is SVO or WVO which has been transesterified. This is a chemical alteration of the oil. Glycerin is removed from the oil molecules with the use of a Hydroxide and Methanol. This makes the oil thinner, but since the glycerin has been removed, it contains slightly less energy than BioFuel. The thin BioDiesel can be used in modern diesel engines without modification. It requires quite a lot of processing to make. The catalyst must be made, glycerin after the reaction must be removed by washing, then the Biodiesel must be finally dried before use. It is a brown/red colour.
BioEthanol – This is ethanol made from the fermentation of various plant crops. It can only be used in Petrol engines.
Using Biodiesel
In order to use Biofuels, one first has to make a few considerations.
The Biofuels are thicker than Fossil Diesel. This means that it is possible to put unnecessary strain on fuel pumps as they have to work harder to move the Biofuel. Older vehicles were less fussy about fuel as the quality was lower than that of today, hence they can use a wider variety of Biofuels more easily. However, the old vehicles used natural rubber for fuel lines and seals, which can be degraded by Biofuels. In the late 90’s, the UK switched to ULSD (ultra low sulphur diesel), which requires synthetic rubber parts. This means that newer cars do not suffer from perishing rubber parts when using Biofuels.
BioDiesel from SVO or WVO is considered to be the best type to use in modern diesel engines. If made correctly, it meets or exceeds the standards required for Diesel.
BioDiesel contains almost no sulphur at all. Engine emissions on Biodiesel contain slightly more Nitrogen based gases (not a good thing), but up to 80% less other harmful gases (definitely a good thing) than the same engine using Fossil Diesel. Some MOT testing stations have thought they had faulty emission test equipment because some readings were lower than the minimum that could be detected.
BioDiesel provides better lubrication for engine parts, which is why it makes the engine run smoother and quieter. It also contains a higher Cetane level than fossil diesel, which means it is more ‘eager’ to detonate in the engine providing better response. In contrast, BioDiesel contains slightly less energy, so overall performance and MPG is seen to reduce.
Using 100% Biodiesel means that the engine is effectively carbon neutral. This is worth the slight drop in power and MPG if you are trying to be more environmentally friendly. A compromise is to use a blend of Biodiesel and fossil diesel. This should give a quieter, smoother engine, with lower emissions, more response, less wear, more MPG due to the better lubrication, and a sweeter exhaust smell. Depending on your engine, about 10% Biodiesel is considered to be the best balance if you want to ignore environmental issues.
When switching to BioDiesel, it may be worth gradually increasing the percentage mixed with Fossil Diesel. There may be no benefit to the engine to start at a low concentration, but at least you will gradually acclimatise to the change! Start by pouring in enough BioDiesel to make 10% in your tank. Then increase by 10% each tankful. You can simply put it in just before you go to the fuel station. 'Splash bending' is perfectly safe and normal practice.
Biodiesel is a very good solvent. It is well known that when first using it, all the crud that has built up in your cars tank and fuel system will be flushed into the fuel filter, clogging it. Depending on your cars mileage and the care taken with fossil fuels, you may need to change the fuel filter in a few hundred miles, or perhaps never. With a nice clean fuel system, your car will produce little or no smoke, and run better.
A major consideration is ambient temperature. All liquids, including Diesel, will freeze (or gel) at some point. Good Biodiesel begins to gel at or around 0C. In cold weather, a blend must be used to make sure it doesn’t go solid in the tank and fuel system (more diesel will prevent it from gelling). Leave a clear sealed container of some outside near you car so you can check it before you start your car at low temperatures. Mix it to the same concentration as in your tank, and you’ll know if it’s safe to use. It should look clear. If you do begin to see very fine particles, the warming of the fuel by the engine should make it OK. Any more than that and you risk a filter clog.
Fuel consistency is vital. In short, if it is not made correctly it may be too thick, contain water, other impurities, or free glycerin (which is basically soap). Do not use Biodiesel that has not been made and tested to meet standards. It should be crystal clear. Any cloudiness or sediment should immediately send alarm bells ringing.
Using an alternative fuel is a big decision. Read all you can about them before coming to a decision, or you could find yourself with a big repair bill! An uneducated BioDiesel user is certain to run into trouble. A well read BioFreak will know how to stay clear of it.
Thanks for reading, and good luck...
