Does modifying a car to use LPG a good idea?


The Sunday Nation


22 January 2023


In the last few years, some Kenyan motorists have modified their petrol cars to run on liquified petroleum gas (LPG). The modification costs Sh55,000 and the LPG goes for Sh89 per litre. This is much heaper than the Sh162 price of petrol in Nairobi. But are the savings worth it?

If we do a direct comparison, the saving on fuel cost is Sh73 per litre. Therefor, to recover the Sh55,000 installation cost, one needs to consume about 750 litres of LPG. How many kilometres will that take and how much time is needed?

This depends of the type of car and the motoring habit of the owner. The typical 1,500cc car consumes petrol at the rate of between 10km/L and 15km/L. This is an average of about 12.5km/L. Thus, such a car would have to run for about 12.5 x 750 = 9,375km before recovering the installation cost of the LPG system. This is approximately two service intervals.

If the car is driven for, say, 50km daily, then it would take 9,375/50 = 187 days to recover the cost of the LPG system. That is, about six months. But we have assumed that the car will consume LPG at the same rate as petrol – 12.5km/L. This is not the case.

The LPG consumption rate is about 20 per cent higher that that of petrol. So, in our example, the car consumes 4L of petrol per day. If it is modified to use LPG, it will run at about 10km/L. Therefore, it will need 5L of LPG daily.

At the price of Sh162/L, the 4L of petrol costs Sh648; and at Sh89/L, 5L of LPG costs Sh445. The daily saving is Sh203. Thus, it would take about 270 days – 9 months – to recover the Sh55,000 LPG modification charge.

From a financial consideration only, this LPG modification is a good idea. It’s greatest challenge, however, is that there are less than a handful of filling stations. It is not uncommon for drivers to queue for many hours waiting for their turn to fill-up. Luckily, the car can still use petrol, but this means that the motorist will not be using LPG on a daily basis.

He may use it on just a quarter of the time; in which case the recovery period goes up to about 3 years. Are you willing to wait that long?

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