NGVs are Clean
NGVs are some of the cleanest vehicles in commercial production today, and produce only 5-10 percent of the emissions allowable, even by today's most stringent standards. NGVs produce 20-30 percent less greenhouse gases than gasoline- or diesel-powered vehicles.
Overall, natural gas is one of the cleanest burning alternative fuels available today. NGVs can reduce nitrogen oxide (NOx) emissions and reactive hydrocarbons which form ground-level ozone, the principal ingredient of smog, by as much as 95 percent. NGVs can also reduce emissions of carbon dioxide by as much as 30 percent, carbon monoxide (CO) by 85 percent and carcinogenic particulate emissions by 99 percent.
Reducing Greenhouse Gas Emissions
The use of compressed natural gas (CNG) in place of gasoline or diesel can help reduce greenhouse gases.
A 2008 "well to wheels" analysis conducted by TIAX, LLC concludes that natural gas offers up to a 30 percent reduction in greenhouse gas (GHG) emissions for light-duty vehicles, and as much as a 23 percent reduction for medium- to heavy-duty vehicles, when compared with gasoline and diesel. The chart below shows the amount of C02 that has been displaced since 1999 by SoCalGas? customers using vehicles powered by CNG instead of diesel. In 2008 alone, that number was almost 229,000 metric tons of CO2!
Clearly, NGVs present one of the cleanest choices for today and tomorrow.
Concept of LNG
LNG is a natural gas (predominantly methane, CH4) that has been converted to liquid form for ease of storage or transport. After being liquefied, it takes up about 1/600 the volume of natural gas in the gaseous state and about 45% the weight of water in equal volume. As a cleaner energy, natural gas is increasingly favored. LNG is proposed to be the prior choice of alternative fuels in many countries, for example, United States, Canada, Europe, and China. As a result, the ratio of natural gas in energy supply increases rapidly. While compressed natural gas (CNG) is just suitable for light-duty vehicles, LNG can be used in road transport, such as heavy-duty trucks and buses. In China, CNG buses and LNG buses were introduced into the bus fleet in Beijing in 1999 and 2012, respectively. After that, more and more cities in China have swift some diesel buses to LNG buses, for example, Guangzhou, Xiamen, and Shenzhen. Heavy-duty vehicle, whose total mass is 14 tons or more, is the main object of promoting LNG vehicles in Shenzhen road freight. Different from light-duty vehicle using diverse fuel (e.g. gasoline, diesel, CNG, and electric), heavy-duty vehicle uses diesel or LNG because the fuel’s energy density must be high enough to meet its power requirement. There are three main types of LNG heavy-duty vehicles in Shenzhen, namely, container tractors, engineering dump trucks, and engineering mixers.
LNG supply safety
The main sources of LNG supplied to Shenzhen include foreign imports and provincial imports. The former is mainly from Australia, Malaysia, and so on. The latter is the Second West-East Gas Pipeline Project, supplying natural gas of about 40?billion m3/year for Shenzhen. Natural gas is transported through pipeline in gaseous state, so it needs complex liquefaction process involving removal of certain components, for example, dust, acid gases, helium, and water. Besides, a small amount of LNG is transported to Shenzhen by cargo transport containers from Inner Mongolia, Xinjiang, and other gas fields. In addition, the contract of Russia’s gas project was signed. A diversity of LNG source markets appear.
Shenzhen has the largest number and the biggest LNG terminals in China. After all of the terminals have become fully operational, the supply capacity of LNG will greatly exceed 11?million tons/year, accounting for around 55% of that in Guangdong province. Along with picking up LNG at adjacent cities, LNG supply is totally guaranteed.
