Petrol vs. LPG: Which Fuel Saves More Money and Emissions?
Petrol is refined liquid hydrocarbon burned in spark-ignition engines; LPG is liquefied petroleum gas, mainly propane-butane, stored under pressure and used in bi-fuel or dedicated gas engines.
Drivers glance at the pump: petrol costs more per litre, LPG less, but needs a tank conversion. The mix-up happens at the bowser—people confuse “gas” with “petrol” because both power cars, yet one drips liquid, the other hisses vapour.
Key Differences
Petrol delivers 34 MJ per litre; LPG gives 26 MJ, so you burn ~30 % more volume. Yet LPG prices sit 40–50 % lower, cutting running costs. Emissions? LPG emits 15 % less CO₂ and ~80 % less NOx and particulates, making it cleaner in city traffic.
Which One Should You Choose?
Choose petrol for factory warranty and long-range resale; choose LPG if you drive 20 000 km+ yearly and can stomach a $2 500–$3 000 tank install. Break-even arrives in 12–18 months; after that, every fill is cheaper and greener.
Does LPG damage engines?
No. Modern LPG systems use vapour-phase injectors that keep valves cool and prevent the carbon build-up often seen in older mixer-ring conversions.
Can I switch fuels while driving?
Yes. Most bi-fuel kits let you flip from petrol to LPG with a steering-wheel button, even at highway speed, without stalling.
Is LPG safe in crashes?
LPG tanks are toroidal steel or composite, pressure-tested to 3× operating pressure, fitted with safety valves and auto-shut-off solenoids—statistically safer than petrol in rear impacts.