Methane Emissions from natural gas vehicles: Global warming

Does methane emission from internal combustion engine a potential threat?

 It is true that this post discuss about the positive or negative impact of methane emissions in the atmosphere due to internal combustion engines. Are you are aware of the methane emissions? Most of the scientists and researchers working in the field of oil/gas or I.C engine know that methane is inert and has high greenhouse effect potential.Did I wrote greenhouse potential? Most of us know that it is CO2  that cause greenhouse effect ie global warming but it is equally true that methane emissions has 21 times more potential than CO2 for causing global warming.

Methane is inert due to its compact structure and high bond energy of C-H bond.Since methane molecule is inert therefore exhaust of the engine using compressed natural gas emit high amount of methane emissions. These emissions are generated when the speed and load conditions  are conducive to generate low temperature (T<1500K) within the cylinder.Practically, when the engine is operating at idling conditions it emits high amount of methane emissions as compared to other engine operating conditions.Extensive research is required to quantify methane emissions at different engine conditions.

Ref: www.glogster.com          Fig 1: Growing population of natural gas vehicles.[IANGV]

Fig 1 indicates that gas engine vehicles are growing exponentially and has increased around 21.6% according to statistics published by IANGV in last ten years (2001-2012). Most of the developing countries such as Argentina, Pakistan, India use compressed natural gas as automobile fuel due to its high availability and low cost benefits.Further, increasing economy in developing countries has boosted the purchasing power of common man that is causing exponential increase in the number of vehicles using gasoline and compressed natural gas as fuel.Unfortunately most  developing countries do not have regulations to control methane emissions. That is one problem that needs immediate attention.

To summarise the reasons of methane emissions :

1. Due to ever increasing use of CNG as fuel due to its low cost and higher availability

2. Due to increasing economy of the developing countries resulting in increasing number of vehicles.

3. Due to inert nature of methane molecule and high bond energy of the C-H bond.

4.Due to low temperature operating conditions

What should be done? It is important to collect data on methane emission to identify the potential sources, engine operating conditions and then use this data to quantify the impact of methane emissions on the atmosphere. Regulations based on this data must be implemented as early as possible in all the countries and methane must be declared as regulated emissions since it is unregulated in most of the developing countries and some developed countries.

I hope that this article will help audience in understanding the impact of methane emissions and can contact us for receiving further details.