A: CNG is natural gas (methane) that is stored and transported under high pressure in its gaseous state. When compared to conventional diesel, CNG has many advantages:

• Lower price*

• Lower carbon intensity based on reduced emissions across its production life cycle

• Lower engine emissions of NOx and particulate matter

*Like all products, pricing subject to fluctuation.

A: Renewable natural gas, or RNG, is biogas that has been upgraded and placed in the conventional natural gas system. It’s produced from multiple sources, including livestock waste, landfills, wastewater sludge, food waste and other organic waste operations. RNG can be used for electricity generation, thermal functions like heating and cooking, bioplastics, and vehicle fuel.

Bacteria naturally break down organic waste and produce raw methane, carbon dioxide (CO2) and other gases. The process is called “anaerobic digestion.

After RNG is upgraded, it can then be injected and transported through natural gas pipeline networks and used as a substitute that is virtually indistinguishable from natural gas. The difference is RNG is produced from biological materials instead of fossil fuel deposits.

A: The two types of CNG infrastructure are time-fill and fast-fill, and the main difference between the two systems are the amount of storage capacity available and the size of the compressor which determine the amount of fuel dispensed and the time it takes for CNG to be delivered. 

A: Generally, fast-fill stations are best suited for retail situations where vehicles arrive randomly and need to fill up quickly. Per the Alternative Fuels Data Center (AFDC), all public CNG stations have a fast-fill option. Fast-fill stations receive fuel from a local utility line at a low pressure and then use a compressor on site to compress the gas to a high pressure. Once compressed, the CNG moves to a series of storage vessels, so the fuel is available for a quick fill-up. CNG can also be delivered via dispensers alongside gasoline or other fuel dispensers. 

CNG at fast-fill stations is often stored in the vessels at a high service pressure (4,300 psi), so the dispenser can deliver it to a vehicle quickly. The dispenser uses sensors to calculate pressure and measure the number of gasoline gallon equivalents (GGEs) delivered to the tank, taking temperature into account.

Chevron and Beyond 6 CNG stations are fast-fill stations. 

A: Natural gas powers more than 175,000 vehicles in the United States and roughly 23 million vehicles worldwide. Natural gas vehicles (NGVs) are good choices for high-mileage, centrally fueled fleets because they can provide similar fuel range support for applications that stay within a region supported by reliable compressed natural gas (CNG) fueling. For vehicles that travel long distances, liquefied natural gas (LNG) offers a greater energy density than CNG, meaning the fuel range is more comparable to conventional fuel. Some of the advantages of natural gas as a transportation fuel include its domestic availability, widespread distribution infrastructure, and reduced greenhouse gas emissions over conventional gasoline and diesel fuels.

The horsepower, acceleration, and cruise speed of NGVs are comparable with those of equivalent, conventionally fueled vehicles. Also, compared with conventional diesel and gasoline vehicles, NGVs offer other air quality benefits beyond greenhouse gas emissions.

The three types of CNG infrastructure are time-fill, gas-fill, and a combination of both.  The main difference between time-fill and gas-fill systems are the amount of storage capacity available and the size of the compressor which determines the amount of fuel dispensed and the time it takes for CNG to be delivered. 
 

Source: Alternative Fuels Data Center: Compressed Natural Gas Fueling Stations (energy.gov)