How to Compare CNG & LPG Vehicles

Vehicles using fossil fuels such as diesel and petroleum emit greenhouse gases into the environment, which are considered a key causative factor for global warming. Compressed Natural Gas (CNG) and Liquefied Petroleum Gas (LPG) are fast becoming preferred alternatives because of their environment-friendliness and lower costs. Both LPG and CNG are fossil-derived fuels, but emit lesser amounts of toxic greenhouse gases resulting in reduced pollution. Many vehicles using CNG or LPG are bi-fuel, which means to say that they can run on either petroleum or CNG/LPG.

Instructions

1

Compare CNG vehicles with their LPG counterparts for their environment-friendliness. LPG is constituted mainly of propane (C3H8) with a little butane (C4H10). In CNG, the key ingredient is methane (CH4). The lesser the carbon-to-hydrogen ratio in the chemical formula of the gas, the better it is for the environment. Thus, methane is better for the environment provided it undergoes complete combustion.

2

Compare CNG vehicles with LPG for their vehicle tank storage requirements. Since LPG is liquefied at normal pressure, it is portable and can be stored in smaller and lighter vehicle storage tanks. CNG is not liquefied, so it requires very high pressure for storage. Vehicles for CNG need to have sturdy and heavy tanks.

3

Compare CNG vehicles with LPG for suitability and performance. Given the bulkiness of CNG vehicle tanks, these vehicles are less spacious. LPG/CNG vehicles are known to have a slightly lower initial pickup but greater acceleration. You may experience cold start problems with these vehicles. It is also important to check for the availability of LNG/CNG in your area to know if you can have consistent fuel supply. LPG fits best with light vehicles such as cars and small vans that run on petroleum, while CNG is ideal for heavy vehicles operating on diesel.

4

Compare CNG and LPG vehicles for safety. CNG is lighter than air and therefore does not puddle. It also has a higher ignition temperature, which means it is difficult to ignite. LPG, on the other hand, is heavier than air and has a lower ignition temperature.

5

Compare CNG and LPG vehicles for the expenses involved. Find out the costs involved for installing CNG/LPG in your area. Calculate running costs depending on the cost per gallon of CNG/LPG and your vehicle mileage and see which is lower. Both LPG and CNG installations require frequent inspections. So, you also need to account for maintenance expenses. Find out if there are any special government concessions for CNG/LPG vehicles in your region that can benefit you.