The subject of Dual Fuel/Bi Fuel cars is one that I have a stronger opinion on than many car enthusiasts. Not only are they a potential option for fuelling the cars I am looking at but I am a current owner of an LPG vehicle…albeit one that currently just runs on petrol. For those who don’t know what a Dual Fuel car is they are essentially regular petrol-run cars, but are slightly modified to run on Liquid Petroleum Gas (LPG), or in some cases Compressed Natural Gas (CNG). Although quite an expensive modification to make and one that requires a large additional fuel tank to be fitted (usually in place of a spare tyre), LPG prices are only a little over half that of regular petrol, so for some buyers the fuel savings could be substantial!
LPG systems can be either factory fitted or added aftermarket for around £2000-£3000; 10 or so years ago it was possible to buy a number of cars in the UK with a factory fitted system – mainly Vauxhalls but also a few Volvos and the Ford Focus. Unfortunately the popularity of diesel and the relative lack of awareness about the benefit of these systems meant that buyers did not flock to the showroom for such vehicles and as a result I don’t believe that any new cars in the UK can be specified with an LPG system as an option (although I am happy to be proved wrong).
However a major market has emerged amongst used car owners, especially those with older/larger 4X4 vehicles who wish to avoid the lethargic performance of similarly aged/priced diesels yet not pay through the nose for the privilege of filling them up. Consider that in just 5 years the price of petrol has jumped by around 30p per litre and its not surprising that there are plenty of people wanting to pay around 50p less per litre than petrol for LPG. Admittedly LPG prices have soared too in these years but 75p/litre is a lot more attractive than 130p/litre!
There are a few negatives though, not least the pretty limited availability of LPG at petrol stations; when my mum owned my car we were lucky enough to have the option of our local supermarket, but further afield it was important to look up nearby stations or resort to using petrol power after a while. The second negative is the aforementioned need for a second fuel tank; this rules out several vehicles who do not feature a spare wheel (ie most new BMW’s) and means that those who still want to carry around a spare must do so in their boot itself! The lack of technical expertise of most drivers nowadays sort of negates this issue as many wouldn’t feel confident enough to change a tyre anyway (including me!), or are happy to carry around a can of tyre sealant instead! Third and finally (beside the initial cost of the conversion) is the high fuel consumption of LPG vehicles even compared to regular petrol models. Now admittedly the fact that the fuel is nearly 50% cheaper negates the 10% ish extra fuel that gets used, but may well be the reason why dual fuel vehicles found favour amongst UK buyers obsessed with ever higher (and arguably unrealistic) MPG figures.
In terms of actual cost the conversion process can cost anything from £2000-£3000 in most cases, or at least so my speculation leads me to believe. When looking at larger, heavier petrol vehicles (typically the candidates for conversion) it is notable that these are usually priced significantly below comparably aged/mileaged diesel versions, plus they tend to have higher equipment levels and much better performance, so the conversion cost can often be fully or partially swallowed by this price gap. On the used market LPG cars barely command any more than untouched cars, so for those willing to take a chance that the vehicle has been well maintained significant savings can be made.
However it is that last point which really spooks me about pressing play on either getting a vehicle converted, or in particular buying one which has already had it done. Now obviously there are certain worries about the quality/professionalism of the installation, but generally it is not hard to find a reputable garage who will do a good conversion if you are willing to pay for it. But of more concern is the additional maintenance associated with dual fuel cars, and whether this schedule has been kept to as rigorously as required. I don’t really know any specific pitfalls to look out for but going from my experience with my car, forgoing the specific (and extra) LPG service resulted in failed injectors-a £2000 bill had I chosen to pay it; as a result I am now driving around a car with an empty LPG tank and no spare tyre! Other worries for me would surround any potential leaks in the system, and rust proofing around the new filler cap.
I am sure that for some people an LPG vehicle makes a lot of sense, and had I had a different experience with my current vehicle then my opinions would very likely be different, but for me personally I won’t be seeking one out despite the potential benefits.