The first one to bite the dust was that a 'bi-fuel' vehicle would be inconvenient. I knew that fuel stations supplying LPG would be few and far between and imagined that switching from gas to petrol would not be entirely hassle free. In fact switching from one to the other is simplicity itself. At the click of a button the driver can seamlessly move from gas to petrol - so can a 12-year-old passenger when her father isn't looking! - and the effects are barely perceivable.
The fact that the local LPG station is no more than 10 minutes from either my home or office also helps to overcome the problem of there not being too many LPG suppliers around but I appreciate other drivers may not be so lucky.
The next misconception to fall by the wayside was that LPG-powered vehicles lack performance. Even though I tried desperately to convince myself that I was right I had finally to admit that I wasn't. An LPG-powered Porsche 911 may lack performance judged against its petrol-powered counterpart but an LPG-powered Mondeo 1.8 doesn't.
On the question of cost savings I felt I must be right. Surely if you go to the expense of ordering new Mondeos with LPG conversions the payback must be more than just a warm feeling as a result of inflicting less damage on the environment.
Wrong again. The facts are these: On the plus side, based on the mpg figures we have been recording, over 60,000 miles the Mondeo on unleaded petrol would cost ú4,752, whereas with gas the cost would be ú3,393, a saving of ú1,359. That is nearly enough to cover the cost of the conversion and with the Government pledged to encourage 'green' motoring by increasing the price differential between traditional and alternative fuels through duty increases on the former, the savings can only go up.
But on the negative side values for bi-fuel vehicles have been shown to be less than their petrol counterparts. CAP Monitor predicts residual values for bi-fuel Vauxhalls and Volvos to be several hundred pounds below their petrol equivalents, despite the price premium for the gas conversion. I believe that most fleet managers would view this as a high price to pay for lower emissions.
Overall the picture for bi-fuel vehicles is encouraging but, if fleets are to seriously consider switching over in large number, the incentives offered by the Government to do so will have to be even better than they are.