Which is better, LPG or CNG?

Auto & Audio June 20, 2012 00:00

By Pattanadesh Asasappakij

17,301 Viewed

Last week I was invited to speak to members of a particular province's chamber of commerce about the present situation - as well as the situation in the next five years - of the auto business.


After I finished, many of them came up to me and continued to discuss the issue, and one asked me how I entered my current profession. After I told him how, he suggested that I write about it for others so it can serve as a guideline, especially for those who may feel lost and exhausted in life. I promised him that if I had the time I would write about it.
While chatting, a few also asked my opinion on this year’s fuel-price situation. They wanted to know whether to choose LPG (Liquified Petroleum Gas) or CNG (Compressed Natural Gas) if they wanted to modify their vehicles for natural gas.
I considered these questions highly interesting, because most of the motorists in Thailand also wonder the same. I get the same questions every day during my radio programme and many wonder why I suggest LPG for some people and CNG for others.
First of all, concerning the fuel price, I said it should be of the same level as the present. There may be some increase or decrease, but it shouldn’t be significant. This is because I believe the crude oil price in the global market throughout this year would remain at no more than US$90 (Bt2,828) per barrel. In the winter, when there is higher demand for diesel, the price could rise to $95 tops.
That’s because every oil producing nation knows that if it allows the price to soar higher than that level, motorists and automobile manufacturers will work harder in finding alternative fuels, or raise production of hybrid vehicles, which also means they will consume less fuel. With more and more people turning to electric cars each day, the importance of oil will eventually decrease.
As for choosing LPG or CNG, the answer depends on many factors.
It also depends on whether you trust the Thai government’s announcement (which isn’t so trustworthy since it had been announced several years back) that the retail price of CNG will be raised according to the procedures and the price of 1kg of CNG will not be more expensive than half a litre of diesel fuel.
The government had also announced that it would promote the expansion of CNG stations so that consumers would not have to line up for hours when having to refuel. It also said that it will float the price of LPG (only for the transportation sector) so that it corresponds with the global price. In other words, there will be no financial support from the government to keep LPG prices stable in the future.
Also, it will not allow new LPG stations to be opened, and will order the Land  Transport Department to carry out strict measures for LPG vehicles when they’re brought in to extend their registration.
If you consider these announcements, then CNG is surely a better choice.
But all the announcements made by the government concerning LPG and CNG has never been achieved. So it is still true today that the cost to modify gasoline engines for use with LPG is at least half or less than half of those for CNG.
The availability of LPG stations is still much higher than CNG, especially in upcountry areas. The difference is so large that it is incomparable, whether in terms of convenience or cost, as well as the mileage between each refuelling – on LPG you can can travel much farther than CNG.
So when anyone asks me about using natural gas, I will first consider the age and value of the vehicle. If it is many years old and has a resale value of lower than Bt300,000, I would recommend LPG due to the low modification cost of Bt10,000-Bt30,000. For CNG, you will need as much as Bt50,000-Bt60,000.
However, for new cars or low-mileage cars, if the owner can easily find CNG stations and plans to use the vehicle for many more years, I would suggest that CNG is a better choice.
For diesel-powered pickup trucks, I do not advise any type of natural gas conversion, since there is still a large number of limitations. If you really want to equip your vehicle with natural gas, I suggest that you change the engine to the gasoline type and then carry out the natural gas conversion. But bear in mind that this will result in a dramatic drop in your vehicle’s resale value to the point where it would be difficult to sell.
As you can see there are factors that determine which type of natural gas you should choose. Car owners need to gather as much information and then decide which fuel type is better for your car, or which fuel type is more accessible. This will ensure that you make the most use of that decision.