Automotive liquefied petroleum gas

Much has been said and written recently on the issue of vehicle emissions. Some of what has been said is fact, some is emotive and based on observations of visible emissions - notably black smoke. Quite frankly, if you think black smoke is bad enough, you are right - but some of the invisible emissions are as bad or worse; particulate matter for example.

Recent correspondence suggests LPG is the solution to pollution in Malta - regrettably it is not.

Many countries are now using alternatives to petrol and diesel to power vehicles and while there are some options for Malta, products such as natural gas are not available nor is there sufficient spare land to grow crops to produce bio fuels. In the mid-1990s, I purchased vehicles and converted them to run on LPG and, in their day, they were cleaner than conventional vehicles.

In the recent past, however, manufacturers such as Ford and General Motors have had considerable difficulty in exceeding the emission levels of Euro 3 for new LPG vehicles and the UK government is reviewing duty incentives given to this fuel as the emissions benefits are eroded.

The government of The Netherlands has already removed many of the incentives to run vehicles on LPG and usage in that country has dropped from 800,000 tonnes to below 500,000 tonnes annually.

The market for automotive LPG in Italy is static at about 1.3 million tonnes annually but the Italians have very cleverly developed vehicles with dedicated engines - you can buy a Fiat Multipla, for example, with the option of a petrol, diesel, LPG, or natural gas engine and all these versions exceed Euro 3. Indeed, all new vehicles sold, powered by whatever fuel, have to achieve at least Euro 3 emissions levels and, to their credit, many manufacturers can reach (or are very near to) Euro 4.

The nub of the problem is that LPG vehicles are mainly a conversion of a petrol engine rather than a dedicated LPG engine, so the vehicle is designed and optimised to run on petrol.

The cost of the best multi-point liquid injection system LPG conversion kit would be about Lm1,600 for a petrol engine and if you wanted to convert a diesel engine the cost would be about Lm6,000 because you would be converting a compression unit to spark ignition. There are much cheaper conversion kits available and these are being dumped in some countries at knockdown prices (particularly Turkey). Not only are these kits poor on emission performance, some of them are unsafe to the point of being downright dangerous.

It is incorrect to assume that vehicles converted to LPG will automatically achieve better emissions performance than the latest petrol and diesel technology. Yes, you lose black smoke, so vehicles look cleaner and there are no particulates in LPG but hydrocarbon emissions have many more components than just smoke and particulates. Unless the vehicle has the latest conversion kit, that has been correctly installed and maintained by a factory-trained technician, then it is highly unlikely that regulated emissions will achieve current standards.

The answer to vehicle emissions in Malta is the same as in any other country - there is no answer until hydrogen becomes the dominant automotive fuel - but that is many years away. To limit the damage, however, there are many steps that can be taken but there is a substantial cost to bear. Improved and affordable public transport, the updating of the vehicle population, regular and correct servicing, replacing old engines with newer technology, exhaust treatment by way of particulate traps and oxidation catalysts - these are some of the short-term actions that can be taken which would make a difference.

And, yes, a dedicated LPG engine correctly maintained would be very clean but even countries such as Italy and The Netherlands have found sales of such vehicles to be very slow despite having a well-developed refuelling infrastructure.