20/06/2008 (Bangkok Post) - This is probably the time where most of us are raking out heads over the need to understand various fuels available in the market. This week's column will make you comfortable with the type of fuels available, both current and future. Let's do diesel first. Petrol heads will have to wait a bit since our government and related agencies are busy scheming with a group of evil politicians; finding a way to scam the citizens of Thailand without an iota of shame.

Let's face it, no previous government or leaders elected to the high office have gone about insulting the people's intelligence and common sense in a manner as blatant as the present administration.

The new age diesel doesn't have to be distilled from crude under the ground. It can be produced by altering other types of fuel. Besides being an alternative, there are many gains.

This type of diesel molecule is most suited for automobiles because of the higher energy value based on equal volume. More importantly, combustion qualities are better which allows for reduced toxic gases and particles released. There are many ways to produce diesel.

The first, is the gas-to-liquid (GTL). I believe that this type of diesel, which is sold in Thailand at a slight premium, is also produced under the same method.

Second method is coal-to-liquid (CTL). There are countries with considerable amount of coal that do not consume as much, allowing them to tap the financial gains therefrom.

Diesel made from coal has good quality and is on par with those made from natural gas. But both of these methods still depend on energy under the earth's surface.

The third method ups the ante. It is called biomass-to-liquids (BTL). Looking at it from the environmental aspect, the first two methods, GTL and CTL, involves using crude drilled from the ground, which is later heat treated resulting in the release of CO2, also known as the greenhouse effect.

BTL comes from biomass. Before converting to biomass, it has already ''consumed'' CO2 from the atmosphere which negates the portion released after being treated with heat in the internal combustion engine.

Biomass is the remnant of vegetables, wood particles amongst other things. The amount of diesel produced is pretty satisfying. Two kilogrammes of wood particles will make about one litre of diesel (correctly called biodiesel).

BTL is both a synthesised form of diesel and biodiesel as well. Its qualities are more suitable for our cars when compared to the type of diesel made from processed vegetable oil.

The product derived from all three methods will be financially challenging since it is still in the experimental stages. It is more expensive then diesel derived from ore-based fuels or crude.

And it is twice as expensive to produce compared to the diesel made from crude. But if you look at it in the long-term, say 10 years from now, the cost of production will reduce considerably.

You will also have to factor in that crude will be more expensive, which by that time, should negate the higher production costs already.

Another type of biodiesel is a type of diesel produced from vegetable oil with ideal criteria through a process called transesterification.

It's not only vegetable oil converted to biodiesel form that can power a diesel engine _ the other alternative is heat derived from the compression of air in the cylinder.

Vegetable oils derived from agricultural produce such as seeds all possess some form of energy. Once the optimal temperature is reached, the result is fire or combustion.

Even oils that aren't considered as up to standard biodiesel, if forced in as energy source for the diesel engine, it will run. But how long it will last and what kind of problems will result remains to be answered.

The aforementioned should not be confused as biodiesel. If we use cooking oil and use it as fuel for our engine, it will run just like any other fuel from your local petrol station. The problem is when your engine will breakdown?

Such a scenario has been tested in foreign countries, and if I remember right, the engine lasted more than 10,000km. I know for sure that the engine suffered serious problems.

Shifting back to biodiesel and its pros and cons, the good is that it reduces CO2 based on the assumption that the biomass to be used in the process had already consumed its share of CO2 _ and there is also no sulphur content in this type of diesel when compared to the kind of diesel derived from ore-based fuels with high sulphur content. Simply put, the sulphur content depends on the specific origins of crude.

Diesel is not all about energy for vehicles. It also lubricates the frictional components such as fuel pumps, especially those of new vehicle models which are subjected to high levels of frictional forces.

To iron out this predicament, a large majority of automakers and engine manufacturers limit the proportion of biodiesel mixed in with ore-based diesel at not more than 5%.

However, certain components such as common-rail fuel injection could deteriorate before their expected life cycle which is why some automakers don't allow use of diesel mixed with biodiesel, regardless of how minute the mixture is rated.

Not only does it not lubricate well enough, biodiesel derived from vegetable oil is more corrosive than conventional ore-based diesel. If used, you risk dissolving certain components of the fuel system that might clog up the fuel filter and render it useless.

Jessada Tandhasetti is former department head of automotive engineering studies at Rangsit University and is currently a technical consultant. He holds a master's degree in automotive engineering from Technical University, Berlin, Germany.