Natural Gas Liquid (NGL) Pipelines

From Global Energy Monitor

Natural Gas Liquids (NGLs) are commercial products that result from the processing of both crude oil and natural gas. This group includes the processed and liquefied products of the hydrocarbon gasses ethane, propane, butane, isobutane, and pentane. For commercial purposes, methane is grouped separately and referred to simply as natural gas or liquefied natural gas (LNG) when liquefied. NGL gasses may be extracted from either oil or natural gas wells, and the resulting products are grouped based on whether they originated from oil or natural gas processing.[1]


NGL gasses occur naturally in oil and gas wells, mixed in with the natural gas (i.e. the methane) or dissolved into the crude oil. The ratio of components varies by well. Overall, ethane occupies the largest share, followed by propane.[1]


Deriving NGLs from Gas Wells

The unprocessed gas extracted from natural gas wells is referred to as wet gas. After extraction, the wet gas is sent to a gas processing plant, also called a "fractionator". There, the various components are separated into dry gas (methane and some of the ethane) and Natural Gas Liquids (NGLs) (ethane, propane, butane, isobutane, and pentane). The resulting products are called Natural Gas Plant Liquids (NGPLs).[3]

Deriving NGLs from Oil Wells

Likewise, after crude oil is extracted from oil wells, the oil is sent to a refinery, also called a "condensate splitter". There, the various components are separated. The resulting products are called Liquefied Refinery Gasses (LRGs). Natural Gas Liquids (NGLs) that were derived from crude oil (as opposed to derived from wet gas) are called Liquid Petroleum Gasses (LPGs).[3]

Hydrocarbon Gas Liquids

Together, the Natural Gas Plant Liquids (NGPLs) and the Liquefied Refinery Gasses (LRGs), are called Hydrocarbon Gas Liquids (HGLs). HGLs include all the commercial products resulting from oil and gas processing with the exception of the dry gas.[3]

There are two types of HGLs:

  • Natural Gas Liquids (NGLs)--also called "alkanes" or "paraffins", their names end in -ane or -ine (ethane, propane, butane, isobutane, natural gasoline, but not methane)[3][4]
  • Refinery olefins--also called "alkenes", their names end in -lene (ethylene, propylene, butylene, isobutylene)[3][4]

Petroleum Products

Petroleum products are the commercial products that result from the processing of crude oil (petroleum) in oil refineries.[5] Petroleum products include Liquid Petroleum Gasses (butane, propane, ethane, and isobutane) as well as diesel fuel, fuel oil, gasoline, kerosene, and liquefied natural gas (LNG).[6] A petroleum-products pipeline is also considered an NGL pipeline if it is carrying Liquid Petroleum Gasses (LPGs), but not if it is carrying non-LPG petroleum products. Likewise, a petroleum-products pipeline is considered a natural gas pipeline if it is carrying LNG.

In 2019, the U.S. Energy Information Administration reported that only 1.5% of crude oil is processed into Hydrocarbon Gas Liquids (HGLs).[7] Only a portion of those HGLs are considered NGLs.


Hydrocarbon Gas Liquids (HGLs) are transported in five types of transmission pipelines. The type of pipeline is defined by the type of product and its destination.[8]

From extraction to processing

  • Y-grade--raw, unseparated HGLs, transports product from its natural source to the processing facility[8]

From processing to further processing

  • E-P mix--usually 80% ethane and 20% propane, transports product from the fractionator plants to ethylene crackers, where the products are used to produce ethylene and other olefins[8]
  • P/P mix--transports products from refineries to special propylene splitters that separates the propane-propylene mixture into higher quality propylene, mostly along the US Gulf Coast[8]

From processing to further processing or storage

  • LPG--mixture of liquefied propane, normal butane, and isobutane, transported by dedicated high vapor pressure (HVP) pipelines or in batches as purity products[8]
  • Purity products--separate, distinct products; mostly ethane, propane, and normal butane[8]

Final products to customers

Pipelines are generally not used to transport the final product to customers. Railroads and trucks are used instead. In the U.S., ships are used for the import and export of NGLs.[8]


Ethane is primarily used to produce ethylene, which is then turned into plastics. Propane is used for heating and as a petrochemical feedstock. A blend of propane and butane, (also called "autogas") is a popular fuel in parts of Europe, Turkey, and Australia.[1]

The U.S. has the greatest NGL production in the world, followed by Saudi Arabia, Canada, Mexico, Russia, Algeria, United Arab Emirates, Norway, Qatar, and Venezuela. Despite having the highest production in the world, even the U.S. doesn't have many NGL pipelines, though the ones they have are very long.[9][1]

GFIT Inclusion Criteria

Project Operational Status

Currently, the GFIT only includes proposed and under-construction NGL pipelines, not operational NGL pipelines.

Project Type

Currently, the Global Fossil Infrastructure Tracker (GFIT) includes NGL pipelines, but not olefin pipelines. Pipelines called "LPG", "Y-grade", "E-P mix", "P/P mix", or "ethane", "propane", "butane", "isobutane", or "natural gasoline" are always included. Pipelines called "olefin", "ethylene", "propylene", "butylene", or "isobutylene" are never included.

Project Size Threshold

Within in-development NGL pipelines, the standard GFIT oil pipeline inclusion criteria applies. This inclusion criteria is based first on the project's transport capacity, but if the transport capacity is not available then the project's length is used. NGL pipeline transport capacity is measured in barrels of oil per day (bpd or b/d). To be included, an NGL pipeline must have a capacity of 6,000 barrels of oil per day or more. If the capacity is not available, then the project must be 100 kilometers or longer. If neither the capacity nor the length are available, the project is included until those figures can be determined. Inclusion criteria details can be found in the Global Fossil Infrastructure Tracker Methodology page.


  1. 1.0 1.1 1.2 1.3 What are natural gas liquids and how are they used?, Energy Information Administration, April 20, 2012
  2. "Hydrocarbon Gas Liquids (HGL): Recent Market Trends and Issues" (PDF). Energy Information Administration. November 2014. Retrieved August 19, 2020.
  3. 3.0 3.1 3.2 3.3 3.4 Hydrocarbon Gas Liquids (HGL): Recent Market Trends and Issues, Energy Information Administration, November 2014
  4. 4.0 4.1 Diane T. Miller, NGL or LPG or LNG – Definitions and Common Uses, OPIS Blog, May 14, 2018
  5. Petroleum product, Wikipedia, accessed August 25, 2020
  6. List of petroleum products, Encyclopedia Britannica, accessed August 25, 2020
  7. Oil and petroleum products explained, Energy Information Administration, May 12, 2020
  8. 8.0 8.1 8.2 8.3 8.4 8.5 8.6 Hydrocarbon gas liquids explained: Transporting and storing hydrocarbon gas liquids, Energy Information Administration, October 31, 2019
  9. Natural Gas Liquids Production by Country, Index Mundi, accessed August 19, 2020