CNG or Compressed Natural Gas is Clean, American, Affordable & Abundant
The CNG used in Natural Gas Vehicles (NGV's) is the same natural gas that is piped into millions of homes for cooking and heating. CNG is ordorless, colorless and tasteless and consist mostly of methane (CH4). 97% of the all the natural gas used in the United States is produced in North America (86% from the U.S. and 12% from Canada). The United States imports over 65% of the oil it uses. Every gallon equivalent of natural gas used is one less gallon of petroleum that has to be imported.
CNG, although a fossil fuel, is different from gasoline, diesel and coal because it does not contain the same harmful compounds found in other fossil fuels. CNG has a negligible sulfur dioxide content, does not contain lead, has a low nitrogen dioxide content, a low particulate content, and a low carbon monoxide content. As well, CNG does not require carcinogenic (cancer-causing) additives to boost octane levels because natural gas is naturally high in octane.
CNG is not toxic or corrosive and will not contaminate ground water.
Were does CNG come from?
Most natural gas consumed in the United States is domestically produced in 2 ways.
Gas streams produced from fossil fuel reservoirs contain natural gas, liquids, and other materials. Processing is required to separate the gas from petroleum liquids and to remove contaminants.
Biogas is a mixture of methane and other gases produced from the decomposition of organic materials. It is produced naturally in landfills, and from the processing of animal waste, sewage, crop waste, and cellulosic and non-cellulosic crops. An energy-wise and greenhouse gas-wise alternative is to capture the biogas from these renewable waste sources, convert that biogas to biomethane, and use the biomethane to displace petroleum or other fossil fuels in transportation or other energy applications.
A dehydration plant controls water content; a gas processing plant removes certain hydrocarbon components to hydrocarbon dewpoint specifications; and a gas sweetening plant removes hydrogen sulfide and other sulfur compounds (when present).
Benefits from using CNG:
Making America less dependent on foreign oil is a national priority.
Reduces urban smog, burns cleaner and produces lower levels of harmful pollutants.
It’s safe and lighter-than-air, CNG is nontoxic and disperses upwards quickly.
It has a higher ignition temperature than gasoline and diesel fuel, which reduces the chances of accidental ignition.
Contains no particulates like diesel fuel and reduces emissions of carbon dioxide - the principal "greenhouse" gas.
Vehicle emissions are lower with natural gas than with gasoline because ignition temperatures are higher and combustion is more efficient.
Engine maintenance cost can be reduced by extending time between oil changes. The particulate materials that are produced during the combustion cycle cause engine oil to get dirty are not present in the CNG.
Readily available. The United States has a huge natural gas resource base. All 50 states and all major metropolitan areas have access to natural gas.
It’s the most practical. Any vehicle can be converted. Half of infrastructrue already exist, we have 6 million miles of underground gas piping.
Economical - Natural gas is piped directly to the fueling station, reducing the cost of transportation.
CNG is actually safer than petroleum. In its natural state, natural gas is odourless. As a safety measure, the gas is odorised with Mercaptan to provide a ready means of leak detection.
CNG has a high ignition temperature of 1,200° Fahrenheit, compared to gasoline of 600° Fahrenheit. CNG has a narrow range of flammability, 5% to 15% of air. The high ignition temperature and limited flammability range make combustion of CNG unlikely.
Natural gas has no known toxic or chronic physiological effects (it is not poisonous).
CNG is lighter than air. Unlike other fuels such as diesel, petrol or LPG, which are heavier than air, and pools on the ground creating a fire hazard and potential pollution to waterways. Should a CNG leak occur, the gas will disperse rapidly upwards into the atmosphere and dissipate.
CNG Fuel Systems - They are "sealed," which prevents any spills or evaporative losses.
CNG Fuel storage cylinders - They are much, much stronger than petrol tanks. The design of the cylinders is subject to a number of "severe abuse" tests such as heat and pressure extremes, gunfire, collisions and fire. The systems are also fitted with valves and other safety devices to prevent leakage and eliminate the risk.
CNG Cylinder Pressure - As CNG is stored at high pressure, it is often perceived that the high pressure of the product makes it more hazardous than other fuels. While a high pressure gas leak tends to make a lot of noise as the gas is escaping. The resulting high concentrations of gas and its tendency to dissipate upwards make it less likely for the gas in the immediate vicinity of the leak to ignite.
Safe Distribution of CNG - In most circumstances, CNG is delivered via underground pipeline networks. This method not only eliminates the need for road tankers to deliver fuel from the refinery, but also the need for ocean going oil tankers to deliver crude oil to the refinery.
CNG Emissions Benefits
Reduction of Benzene by 97% (diesel) and 99% (gasoline)
Reduction of Nitrogen Oxides (NOx) more than 50% (diesel) and 60%-90% (gasoline)
Reduction of Carbon Dioxide (CO2) by 10% (diesel) and 30%-40% (gasoline)
Reduction of Carbon Monoxide (CO) by more than 90% (gasoline and diesel)
Reduction of Non-Methane Hydrocarbons (NMOG) by 50-75% (gasoline)
Reduction of Lead and Sulfur by 100% (diesel and gasoline)
Reduction of Smoke and Particulate Matter (PM10) up to 90% (diesel)
Exposure to the levels of suspended fine particulate matter found in many U.S. cities has been shown to increase the risk of respiratory illness and other health problems. Much of the particulate matter in urban areas is due to transportation. CNG produces very tiny amounts of particulate matter.
CNG produces far less urban emissions than diesel vehicles. For example, even when the stringent 2010 EPA heavy-duty engine emission standards become applicable, CNG will be producing only one-sixth the NOx of comparable diesel engines. NGV's have a deserving reputation for being one of the cleanest transport fuels available, not just with respect vehicle emissions, but also for fuel production. Even when measured against other 'clean' fuels or methods, such as gasoline-electric hybrids, CNG emissions are frequently lower.
CNG also poses fewer environmental hazards than other fuels. In the event of an accident, natural gas dissipates into the atmosphere rather than spilling on to the ground - a major benefit for our waterways and wildlife.
Emissions, what are they?
Carbon monoxide (CO) - Carbon monoxide is a gas that in high concentrations can lead to asphyxiation.
Particulate matter (PM) - Particulates are any materials that are trapped by a gauze filter during emission testing. This means not only is it a measure of soot particles but also liquid aerosols that have been trapped. Particles from any source that enter the lung can often cause lasting damage. In addition, particles that are highly reactive are believed to cause further damage. Obviously the best thing is have the fewest particles possible to reduce any risk as much as possible. PM emissions have been the key focus of recent international emission standards.
Nitrogen oxides (NOx) - These are one of the constituents of photochemical smog/haze. In many areas it is the amount of NOx that is released that governs air quality. This is because there is already a large amount of HC in the air ready to react with the NOx. NOx has also been the key focus of recent international emission standards.
Hydrocarbons (HC) - Sometimes excluding Methane (NMHC) - As mentioned above HCs react with NOx to form smog/haze. As methane is a 'non-reactive' hydrocarbon, it is not involved in this smog forming process. When NGVs are discussed, the methane emission is usually excluded from the air quality measuring process.
Greenhouse' Gases - As CO2 is usually the more predominant greenhouse gas, greenhouse emissions factors are usually quantified in CO2 equivalents. As methane is also a greenhouse gas, any unburnt methane emissions are usually included in NGV greenhouse emissions calculations. Due to the increasing efficiency of natural gas engines, this problem is progressively being minimised.