Is compressed natural gas more polluting than gasoline?
Countries around the world have reduced their greenhouse gas emissions significantly by replacing facilities such as coal-fired power plants with their natural gas equivalent.
But can switching from gasoline to natural gas vehicles also provide environmental benefits and reduce pollutant emissions?
Find out if natural gas and compressed natural gas (CNG) are more polluting than gasoline or if, on the contrary, they are a green alternative to fossil fuels.
Natural gas combustion generates fewer air pollutants than gasoline combustion
To accurately compare the amount of pollution generated by the combustion of different fuels, it is necessary to measure the amount of pollutants emitted to produce the same amount of energy.
This energy is usually expressed in joules or gigajoules (1 billion joules) and refers to the heat produced by burning the fuel. One joule is therefore a very small amount of energy. For example, a 100-watt incandescent light bulb uses 360,000 joules in one hour of use.
This may seem complex, but it effectively compares fuels in different forms: gaseous in the case of CNG and liquid in the case of gasoline.
Natural gas combustion produces less CO2 than gasoline
Carbon dioxide, commonly known as CO2, is the main greenhouse gas emitted by natural gas vehicles, gasoline and diesel.
According to statistics provided by the U.S. Energy Information Agency, when 1 billion joules (or gigajoule, GJ) of gasoline is burned, the smoke released contains about 71 kilograms of carbon dioxide (CO2).
Methane, the main component of natural gas and CNG, emits much less: only 53 kg. For the same amount of raw energy produced, natural gas therefore emits 27% . This is one of the main reasons why CNG vehicles do not need emission control systems.
Natural gas engines emit less gas and toxic substances
However, CO2 is not the only pollutant emitted by car and truck engines. With that said, for the same distance travelled, a vehicle with a CNG engine will generate much less.
For example, CNG vehicle emissions contain very little nitrous oxides (also known as nitrogen oxides or NOx), which are among the pollutants responsible for smog. The same is true for sulphur oxides (SOx) and carbon monoxide (CO).
Gasoline engines also emit a significant amount of fine particles and ash into the atmosphere. These can cause respiratory diseases and cardiovascular symptoms. Natural gas, on the other hand, emits no ash, almost no sulfur, and no toxic metals or fine particles.
CNG vehicles create less noise pollution than gasoline-powered vehicles
The noise pressure level of a CNG engine is lower than that of a conventional combustion engine.
This means that CNG vehicles are quieter and produce less noise pollution. This feature makes them a particularly good choice in densely populated areas or for night-time use.
Natural gas is safer for ecosystems
Even a very small amount of gasoline can contaminate a body of water or groundwater. This liquid fuel can seep into the ground and reach drinking water sources. Therefore, it requires considerable precautions in transportation and storage.
Because natural gas is lighter than air, it rises and dissipates quickly into the atmosphere. It therefore has no risk of spillage. If it comes into contact with water, it will not mix with it, which eliminates the risk of contamination.
Operators of CNG fueling stations therefore do not have to deal with potential tank leaks, which is a major concern for the managers of liquid fuel stations.
Natural gas can come from renewable sources
Unlike gasoline, which is essentially obtained by refining raw oil from fossil sources, natural gas can come from renewable sources. This renewable natural gas can also be compressed to produce CNG for use in heavy duty and lightweight vehicles.
Renewable natural gas (RNG), also known as biomethane, is chemically identical to fossil-based natural gas, but produces even fewer GHG emissions throughout its life cycle. Mixing even relatively small amounts of RNG with fossil natural gas can therefore provide significant benefits in terms of GHG emissions.
Biomethane is mainly obtained by collecting gases from the decomposition of residual materials.
Compressed natural gas: a less polluting alternative to gasoline
In conclusion, natural gas is less polluting than gasoline in every aspect. Whether during its extraction, transportation, storage or combustion, it is less harmful to the environment and human health.
It is no surprise that CNG is becoming increasingly popular in the transportation industry, which has made it a fuel of choice in the fight against climate change.
If you want to increase the use of natural gas and reduce your dependence on more polluting traditional fuels, contact our experts. As leaders in the field of CNG vehicles, they will be able to provide you with sound advice, whether you are buying or leasing environmentally friendly vehicles.