In 2014, up to 27 per cent of the ethane in U.S. gas, a raw material for plastic, was burned as fuel instead, because too few plastics plants and export ships could take it

Why it matters: ethane left in the gas does not become plastic; it goes to gas users with the rest of the gas and is burned in their furnaces, stoves and power plants, and it makes the gas hotter. The U.S. Energy Information Administration (EIA) found that in July 2014 the gas delivered in West Virginia carried 6 per cent more heat than the national average¹, and in North Dakota 5 per cent more, which it said may indicate ethane left in; and that "stoves and other gas-fueled appliances typically require natural gas to be within a certain range of Btu content" (Btu, British thermal units, measure heat). The choice is made at gas processing plants, which can take the ethane out of the gas and sell it as a liquid, mostly to be made into ethylene for plastics, or leave it in. EIA calls leaving it in ethane rejection. In May 2014 EIA reported estimates of 200,000 to 400,000 barrels a day, about 15 to 27 per cent of the ethane in the gas the plants processed. Plants have taken more of it out since, as plastics plants and export ships took more, but EIA wrote in 2025 that ethane can still be left in when its price comes close to that of gas.

Archived page. A finished record from the monthly figures of the U.S. Energy Information Administration (EIA) through July 2026 and its articles of 2013 to 2025; it will not be updated.

Ethane against the other liquids

Gas plants produce five liquids: ethane, propane, two butanes and natural gasoline. More gas processed means more of all of them, so a rising volume of ethane says little on its own. Ethane's share of the five says more, because ethane is the one EIA singles out: "Unlike heavier natural gas plant liquids—such as propane, butanes, and natural gasoline—significant amounts of ethane can be left in natural gas transported on pipelines to natural gas customers". When plants leave ethane in, its share falls. EIA used the same measure in² 2016, reporting the share's fall from 42 per cent in 2010 to 34 per cent in 2015.

The chart shows ethane's share month by month; it swings by a few points within each year. Below it, ethane and propane production, each on its own scale.

EIA's monthly field production of natural gas plant liquids, January 2009 to July 2026, as fetched on October 25, 2026; the latest months are preliminary and are revised. The share is ethane over EIA's total for the five liquids³.

What EIA said about the price

In EIA's account, ethane sold for about the price of natural gas, measured by the heat each carries, from late 2012 to mid-2017, and at a premium since. This page found no ethane price series that is free to republish⁴, so it computes no price signal of its own and gives EIA's words, at the dates EIA wrote them.

Prices are for ethane at Mont Belvieu, Texas, in EIA's words "the main pricing hub for NGPLs". MMBtu is a million British thermal units, a measure of heat; EIA gives ethane's approximate heat content¹¹ as 2.783 MMBtu a barrel, so a price per gallon and a price per MMBtu can be compared.

The price is not the whole of it. In 2016, EIA described what had changed¹²: "Beginning in 2012, the availability of relatively inexpensive ethane encouraged a wave of investments in ethane-consuming petrochemical plants and export facilities". It dated the first ship exports of ethane, from a terminal at Marcus Hook, Pennsylvania, to March 9, 2016, and wrote in 2019 that "Several new petrochemical crackers were commissioned in the United States in 2018¹³", and that ethane is recovered "if ethane's value is sufficient to cover the additional costs to produce and distribute the ethane to markets". Of the record year 2024, it wrote: "Increasing ethane recovery associated with natural gas production and continued growth in the domestic and global petrochemical sectors drove these increases".

Method

Volumes. EIA's monthly field production of natural gas plant liquids by product, United States, thousand barrels a day: ethane, propane, normal butane, isobutane and natural gasoline, and their total, which the build checks equals the sum of the five each month. A year's share is the mean of its months' shares; the share over the latest twelve months, August 2025 to July 2026, is their ethane over their total. Growth since 2015 compares the latest twelve months with 2015's average. EIA has also compared ethane with the gas produced: in 2019 it wrote that "Dry natural gas production increased much more slowly over this time period, indicating that natural gas processors were extracting more, and consequently, rejecting less ethane". This page uses the share because it is national and monthly.

The 2014 estimate. "Estimates of ethane rejection volumes range between 200 and 400 Mbbl/d" (thousand barrels a day), EIA wrote on May 8, 2014, without saying whose estimates they were. Against the 1,091 thousand barrels a day plants recovered on average in 2014, that range is 15.5 to 26.8 per cent of the ethane recovered and left in together.

Checked against EIA. The build reproduces figures EIA printed from the same series, among them ethane's share, 42 per cent in 2010 and 34 per cent in 2015, and 1.71 million barrels a day in 2018; the code lists all of them. Statements of EIA's that the series does not reproduce are left off the page.

Limits

This is a record of what EIA published, not a model. Without a price series it cannot say month by month when recovering ethane paid; it can only show the volumes and repeat what EIA wrote. The share moves with the gas itself, wetter or drier from one basin to the next, as well as with how much ethane plants leave in, so it shows the direction of rejection, not its amount, and it cannot show how much ethane is still left in the gas today. EIA wrote in 2025 that "when ethane prices and natural gas prices are closer, more ethane can be left in the natural gas stream and sold for its heat value". The totals are national: EIA found rejection "particularly evident in 2013 in the Marcellus Shale play in Pennsylvania, West Virginia, and Ohio, as well as in the Bakken formation in North Dakota", and a national share blurs where it happened.

The code

Python: the fetch script, recording where and when each EIA file came from; the readers, which read every figure and quotation out of those files; the payload builder with its checks against EIA's printed figures; the page generator; and the tests. The archive carries the payload, not EIA's files. 29 KB.

Download source All code

Sources

1. U.S. Energy Information Administration, Today in Energy, “Newly released heat content data allow for state-to-state natural gas comparisons”, 14 October 2014.Heat content of delivered gas in West Virginia and North Dakota, July 2014, and what it may indicate; the Btu range appliances need; where rejection was most evident in 2013.
2. U.S. Energy Information Administration, Today in Energy, “First shipment of ethane from U.S. Gulf Coast arrives in Europe”, 22 September 2016.Ethane as a feedstock for plastics; propane, butanes and natural gasoline cannot be left in the gas as ethane can; the choice depends on prices, demand and the plants' ability; ethane's share of NGPL, 42% in 2010 and 34% in 2015.
3. U.S. Energy Information Administration, Natural Gas Plant Field Production, U.S. field production of natural gas liquids by product, thousand barrels per day, monthly (PET_PNP_GP_DC_NUS_MBBLPD_M), fetched 25 October 2026.Every volume and share on the page: ethane, propane and the total of the five plant liquids, 2009 to the latest month.
4. U.S. Energy Information Administration, Copyrights and Reuse.EIA's publications are public domain; material licensed from private organizations may be protected.
5. U.S. Energy Information Administration, Today in Energy, “2012 Brief: Natural gas liquids prices down in 2012”, 15 January 2013.What ethane rejection is, its limit, and when it occurs.
6. U.S. Energy Information Administration, Today in Energy, “Natural gas liquids prices trend down since the start of 2012”, 29 July 2013.The first-half 2013 price, 27 cents a gallon, and ethane left in the gas because it was low against gas.
7. U.S. Energy Information Administration, Today in Energy, “High value of liquids drives U.S. producers to target wet natural gas resources”, 8 May 2014.Ethane priced below gas and sold as natural gas; the estimates of 200 to 400 thousand barrels a day.
8. U.S. Energy Information Administration, Natural Gas Weekly Update, week ending February 13, 2019, released February 14, 2019, “As energy markets are showing more love, ethane is feeling less rejected”.Prices within $1.00/MMBtu of Henry Hub from late 2012 to mid-2017; EIA's test of rejection against dry gas production.
9. U.S. Energy Information Administration, Today in Energy, “EIA expects U.S. ethane production to grow by 9% in the second half of 2022”, 31 August 2022.Ethylene as a precursor of plastics and resins; the premium since 2017.
10. U.S. Energy Information Administration, Today in Energy, “U.S. ethane production, consumption, and exports set new records in 2024”, 20 March 2025.The 2024 prices as EIA states them; the Houston Ship Channel price; the 2024 record and its causes in EIA's words; Mont Belvieu as the main pricing hub.
11. U.S. Energy Information Administration, Monthly Energy Review, September 2026, Appendix A, Table A1, Approximate Heat Content of Petroleum and Biofuels.Ethane's heat content, 2.783 million Btu a barrel.
12. U.S. Energy Information Administration, Today in Energy, “Ethane production expected to increase as petrochemical consumption and exports expand”, 1 April 2016.The ethane in raw gas exceeding what could be consumed and exported; prices at or below gas; the wave of investment from 2012; the first waterborne exports, March 2016; 1.1 million b/d in 2015.
13. U.S. Energy Information Administration, Today in Energy, “U.S. hydrocarbon gas liquids production reaches 5 million barrels per day in 2018”, 4 June 2019.Recovery when ethane's value covers the costs; the crackers of 2018; 1.71 million b/d in 2018, 20% above 2017.